Semaglutide: The Definitive Guide

What is semaglutide?

Semaglutide is a prescription medicine that copies GLP-1, a hormone your gut releases after you eat. It lowers blood sugar, makes people feel full sooner and hungry less often, and is used for type 2 diabetes, weight loss and lowering heart and kidney risk.

GLP-1 stands for glucagon-like peptide-1; a peptide is a short chain of amino acids. Semaglutide is a lab-made version of GLP-1 with three changes. One protects it from being broken down quickly, one makes sure only a single fatty-acid chain attaches, and that fatty-acid side chain lets it ride on albumin, a protein in the blood. Together they stretch its half-life to about a week, so one injection lasts a whole week. [1], [2]

Novo Nordisk makes the brand-name products. The same active ingredient goes by different names depending on the dose and the condition it is approved for:

[3], [4], [1]

People also come across semaglutide as compounded vials, "research" vials sold online and dissolving tablets or drops. These products are not FDA approved, and their contents and absorption can differ from the real medicine. [5]

Typical Semaglutide Protocols

The most common schedule in the labels and the reviewed dosing sources is the Wegovy injection ladder: 0.25 mg once a week, raised every 4 weeks through 0.5, 1 and 1.7 mg to a 2.4 mg maintenance dose from week 17. [1], [6], [7], [8]

Titration Raising the dose in steps

Each step lasts 4 weeks to limit stomach side effects. If a step is not tolerated, the Wegovy label says to consider waiting another 4 weeks before the next increase, and 1.7 mg is also an approved long-term dose (for MASH, only when 2.4 mg is not tolerated). Adults who have tolerated 2.4 mg for at least 4 weeks can move to 7.2 mg if more weight loss is clinically needed. Ozempic moves up to 1 mg and then 2 mg only when more blood-sugar control is needed. [1], [3]

Breaks and cycles

Not applicable in the labels: semaglutide is a continuous, long-term treatment with no planned breaks. In a follow-up of the STEP 1 trial, people who stopped regained, on average, about two-thirds of the weight they had lost within a year (see stopping). If a Wegovy injection is missed, take it if the next dose is more than 2 days away; otherwise skip it. After 2 or more missed weeks in a row, the label says to restart the step-up at a lower dose. Ozempic allows a missed dose within 5 days. A missed tablet is skipped, and the next one is taken the following day. [1], [3], [4], [9], [10]

Read the units: doses are in milligrams (mg). Branded pens deliver fixed doses, so there are no syringe units to count. Tablet and injection milligrams are not interchangeable: in adults without type 2 diabetes, a daily 25 mg Wegovy tablet gives average blood levels similar to a 2.4 mg weekly injection. Units only come up with vials; see how units convert. [1]

Each row is a separate labeled schedule, not a step to move through, apart from the conditional move from 2.4 mg to 7.2 mg. These are the labeled doses; prescribers adjust them for tolerance, response and the condition being treated. [1], [3]

What are the tablet doses?

Tablets have their own ladders. They are taken once a day, first thing in the morning on an empty stomach with no more than 4 ounces (about 120 mL) of plain water, at least 30 minutes before food, drink or other pills. [1], [4]

Where schedules differ: 7.2 mg, lower doses, compounded vials, microdosing and stopping ↓

What is semaglutide commonly used for?

Most people look into semaglutide for one of three reasons: they want to lose weight, they have type 2 diabetes, or a doctor has raised it to lower their heart or kidney risk. Many also describe a quieter "food noise," the constant background thinking about food. [1], [3], [22]

The uses below are approved for specific products and people. Using a product for something outside its label, or using an unapproved product, is a different situation from the trials described here.

Weight loss

This is the use most people search for. Wegovy injection and Wegovy tablets are approved for adults with obesity, or with overweight plus a weight-related health problem, alongside a reduced-calorie diet and more activity. Wegovy injection is also approved for children 12 and older with obesity. In the STEP 1 trial, adults on 2.4 mg a week lost an average of 14.9% of their body weight over 68 weeks, compared with 2.4% on placebo. About half lost 15% or more. In teenagers with obesity (STEP TEENS), BMI fell by 16.1% over 68 weeks, compared with a 0.6% rise on placebo. [1], [23], [24]

Doserly

How much weight did people lose in large trials?

Average change in body weight (%).

STEP 1

Adults without diabetes · 2.4 mg weekly injection · 68 weeks. Semaglutide −14.9%; placebo −2.4%.

STEP 2

Adults with type 2 diabetes · 2.4 mg weekly injection · 68 weeks. Semaglutide −9.6%; placebo −3.4%.

STEP 5

Adults without diabetes · 2.4 mg weekly injection · 104 weeks. Semaglutide −15.2%; placebo −2.6%.

STEP UP

Adults with obesity · 7.2 mg weekly injection · 72 weeks. 7.2 mg −18.7%; 2.4 mg arm −15.6%; placebo −3.9%.

OASIS 4

Adults with overweight or obesity · 25 mg daily tablet · 64 weeks. Semaglutide −13.6%; placebo −2.2%.

Each trial had its own placebo group; bars are not a head-to-head comparison.

Results depend on the dose, the form, the population and how long the trial ran.

Type 2 diabetes

Ozempic, Rybelsus and Ozempic tablets are approved to improve blood-sugar control in adults with type 2 diabetes. They lower HbA1c, a blood test that reflects average blood sugar over about three months. In an early 30-week trial, weekly 0.5 mg and 1 mg injections lowered HbA1c by about 1.5 points, compared with almost no change on placebo. In adults with obesity and prediabetes (STEP 10), 81% had normal blood sugar after a year on 2.4 mg, compared with 14% on placebo. [3], [4], [25], [26]

Heart and kidney protection

Some approvals are about preventing events. Wegovy is approved to lower the risk of heart attack, stroke and heart death in adults with heart disease and excess weight. Ozempic has similar approvals for adults with type 2 diabetes and heart disease, and for slowing kidney disease in type 2 diabetes. Rybelsus and Ozempic tablets are approved to lower heart risk in adults with type 2 diabetes at high risk. [1], [3], [4], [27], [28]

A liver disease called MASH

MASH (metabolic dysfunction-associated steatohepatitis) is fatty liver disease with inflammation and scarring. Wegovy has an accelerated US approval for MASH with moderate to advanced scarring but no cirrhosis, based on liver biopsies; a longer trial is checking whether it prevents liver failure. [1], [29], [30]

Other conditions studied in trials

Trials have also tested semaglutide for heart failure symptoms, knee arthritis pain, leg-artery disease and alcohol use. Some results were positive. The large Alzheimer's disease trials found no benefit. These are covered in the human research section. [31], [32], [33], [34], [35]

Where do semaglutide protocols differ?

The labeled ladders are clear. The confusion comes from tablets versus injections, different top doses in different countries, custom schedules for vials, "microdosing" and stopping.

Doserly

How do the labeled Wegovy doses step up?

Official Wegovy product labels.

Wegovy injection (once weekly)

0.25 mg in weeks 1–4, 0.5 mg in weeks 5–8, 1 mg in weeks 9–12, 1.7 mg in weeks 13–16, then 2.4 mg from week 17. 1.7 mg is also a labeled maintenance dose.

7.2 mg option (some adults)

Adults, after at least 4 weeks on 2.4 mg, if more weight loss is clinically needed (US). EU: starting BMI 30 or more. Not in Canada's label.

Wegovy tablets (once daily)

1.5 mg on days 1–30, 4 mg on days 31–60, 9 mg on days 61–90, then 25 mg from day 91.

Tablet and injection mg are not interchangeable. In adults without type 2 diabetes, 25 mg tablets give average blood levels similar to a 2.4 mg weekly injection.

Tablet and injection milligrams are separate scales.

Is the number for a tablet or an injection?

A tablet dose and an injection dose cannot be compared by their milligrams. So little of a swallowed dose is absorbed that tablets contain far more semaglutide; in adults without type 2 diabetes, a daily 25 mg Wegovy tablet gives average blood levels similar to a 2.4 mg weekly injection, though levels vary more between people. In people with type 2 diabetes, average levels on the tablet were lower. [1]

Switching follows fixed label rules, not arithmetic. Someone on Wegovy 2.4 mg injections can start 25 mg tablets one week after the last injection; going the other way, the 2.4 mg injection starts the day after the last 25 mg tablet (or 1.7 mg if the tablets were not tolerated). Someone on Ozempic 0.5 mg injections can start Rybelsus 7 mg or 14 mg one week later. Even the two diabetes tablets differ: Rybelsus 7 mg matches Ozempic tablets 4 mg, and 14 mg matches 9 mg, and the label says not to switch between them in the first 30 days. [1], [4]

Why does Ozempic stop at 2 mg and Wegovy at 2.4 mg or 7.2 mg?

They are the same medicine approved for different jobs. Ozempic's doses were set in diabetes trials, where 2 mg lowered HbA1c slightly more than 1 mg (2.2 versus 1.9 points); Wegovy's were set in weight trials. [3], [36], [1]

Does everyone need to reach 2.4 mg?

No. The label allows 1.7 mg as a long-term dose. In STEP 6, in East Asian adults, 1.7 mg led to 9.6% average weight loss, compared with 13.2% for 2.4 mg and 2.1% for placebo. [1], [37]

Real-world use often stays lower. In one large US health-record study, about 8 in 10 people starting semaglutide or tirzepatide for weight were on lower maintenance doses, and average one-year weight loss was 8.7%. [38] In community education groups, a common teaching is to hold a dose while it still works rather than stepping up on a calendar.

What changes at 7.2 mg?

In the STEP UP trial, adults with obesity lost 18.7% on 7.2 mg over 72 weeks, compared with 15.6% on 2.4 mg and 3.9% on placebo. In adults with type 2 diabetes, 7.2 mg led to 13.2% average loss versus 3.9% on placebo. [39], [40]

The higher dose brings a new side effect: unusual skin sensations such as tingling, burning or skin that hurts to the touch (dysesthesia), in 22% on 7.2 mg versus 6% on 2.4 mg and 0% on placebo. Hair loss was 6%, 3% and 1%. [1]

The rules differ by country: the US allows 7.2 mg for adults when more weight loss is clinically needed, the EU also requires a starting BMI of at least 30, and Canada's current label does not include it. In the EU and UK, 7.2 mg can also be given as three 2.4 mg injections, one after another, depending on the pen. [1], [11], [41], [12], [42]

Do compounded and "research" vials follow the same steps?

Many do not. Some websites copy the Wegovy ladder onto vials; others use kit-based steps such as 1.5 mg and 2.5 mg, top out at 2.5 mg a week, or split the weekly dose in two. None are approved schedules. [43], [19], [20], [44], [45]

The product itself is the bigger difference. The FDA says the semaglutide shortage ended in February 2025, which ended the exception that let pharmacies make routine copies. A pharmacy can still compound a version that a prescriber documents is meaningfully different for a specific patient. The FDA also says the salt forms some compounders used (semaglutide sodium and semaglutide acetate) are different ingredients, and it knows of no lawful basis for using them in compounding. [46], [5]

What is "microdosing" semaglutide?

There is no agreed meaning. Some pages mean doses below the 0.25 mg start (0.05–0.2 mg a week); others sell the normal 0.25 mg start as a "microdose" or define it as a quarter of a standard dose. [47], [48], [49], [44], [50]

No completed trial has tested a microdosing schedule. As of September 23, 2026, ClinicalTrials.gov lists a few company-sponsored studies, such as an AgelessRx trial of low-dose semaglutide and a Noom study following people who use compounded semaglutide, and none has posted results. A separate university trial in people with HIV plans to compare stopping with lowering the dose to 0.5 mg weekly after stepping up to 2 mg. It calls this lower dose "microdosing", but 0.5 mg weekly is also a standard Ozempic maintenance dose on the label. [51], [52], [53], [3]

An early trial did use small amounts, 0.05–0.4 mg, but injected every day, so the weekly totals were 0.35–2.8 mg and are not microdoses. In a 2026 proposal, the FDA said the "microdosing" argument for making bulk semaglutide did not show that approved products could not be used. [54], [55]

Once a week or split into two injections?

The labels say once a week, on the same day each week, at any time of day. The one-week half-life is why a single weekly dose is enough. Some clinics and forum users split the weekly dose in two to ease side effects or end-of-week hunger. No trial has compared the two approaches. [1], [45], [56], [57]

The injection day can move. The US labels and Canada's Ozempic monograph allow a change if at least 2 days (48 hours) have passed since the last dose; the EU product information and Canada's Wegovy monograph ask for at least 3 days (72 hours). [1], [3], [58], [59], [11], [41]

How do milligrams convert to syringe units?

Branded pens do not use units. Units appear only with vials drawn into an insulin syringe, and they measure volume, not drug. On a U-100 syringe, 100 units equal 1 mL, so the amount of semaglutide in each unit depends on the vial's concentration. [60]

For example, a vial at 2.5 mg per mL holds 0.025 mg per unit, so 0.25 mg is 10 units. At 5 mg per mL, the same 0.25 mg is only 5 units. Copying a number of units from someone using a different vial can double or halve the dose. The FDA has reported overdoses of 5 to 20 times the intended amount from unit and concentration mix-ups. Doserly's reconstitution calculator works out the arithmetic for any vial and shows each step. [60], [61]

What happens when you stop semaglutide?

The labels describe long-term treatment, and the stopping studies show why: after treatment ends, weight usually returns. Semaglutide itself takes about 5 to 7 weeks to leave the body after the last dose. [1]

• Weight. Two studies followed people after stopping. STEP 4 was a randomized stopping trial: everyone took semaglutide for 20 weeks and lost about 10.6%. Then a third were switched, without knowing it, to placebo. Over the next 48 weeks, those who continued lost another 7.9%, while those switched to placebo regained 6.9%. In the STEP 1 extension, an exploratory follow-up of 327 people who stopped after 68 weeks, when the trial's lifestyle support also ended, people had regained about two-thirds of their lost weight a year later; on average they ended 5.6% below their starting weight. [10], [9]
• Blood pressure, blood sugar and other measures. In the STEP 1 extension, the improvements seen on treatment drifted back toward where they started. [9]
• Estimates across drugs. A 2026 review of GLP-1 medicines estimated that about 60% of lost weight returns within a year of stopping. Another, which analyzed semaglutide and tirzepatide together, estimated regain of about 0.8 kg a month; its forecast beyond one year is a projection, not an observation. [62], [63]

Doserly

What happened to weight after people stopped?

Randomized human trial (STEP 4) and an exploratory trial extension (STEP 1).

STEP 4: weeks 0–20

Everyone took semaglutide for 20 weeks and lost 10.6% on average.

STEP 4: weeks 20–68

From the week-20 weight, people who kept taking semaglutide (535 people) lost a further 7.9%; those switched to placebo (268 people) regained 6.9%. Changes after week 20 are measured from the week-20 weight. 803 people randomized at week 20.

STEP 1 extension: one year after stopping

Semaglutide: 0% at week 0, −17.3% at week 68 when treatment stopped, then −5.6% at week 120. Placebo: 0%, −2.0%, then −0.1%. Regain of 11.6 percentage points (semaglutide) and 1.9 (placebo) between weeks 68 and 120; exploratory extension subset (327 people).

Lines join measured time points only.

People who kept taking semaglutide kept losing weight; those who stopped regained much of what they had lost.

Stopping is common in real life. In a Danish study of 157,822 people who started semaglutide for weight, about half had stopped within a year (a gap of 60 days or more), and about 1 in 4 of those who stopped restarted within three months. The records could not show why people stopped or what happened to their weight. [64]

Tapering, breaks and "receptor resets." The labels give no taper schedule. [1] One dosing website describes a 16-week step-down from 1.7 mg through 1, 0.5 and 0.25 mg. [65] In community education groups, educators disagree: some teach step-downs of about 4 weeks each or longer gaps between doses, some advise staying on, and a few promote breaks to "reset" GLP-1 receptors.

No completed trial has compared tapering with stopping all at once. An uncontrolled 2024 conference report, written by the company running an online weight program, estimated that people who tapered off were about 1.5% lighter 26 weeks later, with a range from 6.4% lighter to 3.3% heavier, assuming nobody restarted. A randomized trial called REST, comparing a 16-week taper with stopping, has published only its plan. No study shows that breaks restore the effect. [66], [67]

Do semaglutide tablets and injections work the same way?

They deliver the same ingredient by very different routes. A subcutaneous injection goes into the fatty layer under the skin of the belly, thigh or upper arm; 89% of the dose reaches the blood, peaking 1 to 3 days later, with similar exposure at all three sites. [1]

A tablet has a harder job, because the stomach normally breaks peptides down before they can be absorbed. The tablets contain an absorption helper called SNAC (salcaprozate sodium). Human and dog studies showed that semaglutide is absorbed in the stomach, right next to the dissolving tablet. Laboratory and animal studies suggest SNAC shields it from digestive enzymes there and briefly helps it cross the stomach lining. Even so, only about 1% to 2% of a Wegovy tablet dose reaches the blood, and a model of the earlier diabetes tablet put the figure at 0.8% under the recommended conditions. [1], [68], [69]

That fragile absorption is why the tablet rules are strict. In a human imaging study, blood levels were about 70% higher when a tablet was taken with 50 mL of water than with 240 mL, and absorption rises the longer a person waits before eating: hence the empty stomach, the 4-ounce limit and the 30-minute wait. [70], [1]

Are drops, troches and nasal sprays the same?

No. Sublingual (under-the-tongue) troches, drops and similar products are not approved forms of semaglutide, and no published clinical trial has measured how much of a dose reaches the blood or how it compares with approved products. One compounding list sold 1 mg troches taken every other day; one guide called injection doses "equivalent" for under-the-tongue use without any absorption data. [71], [72], [5]

How should semaglutide be stored, and how long does it last?

Each product's label sets its storage rules, and they differ by product and by country, so the leaflet in your own box is the final word. In short, pens start in the fridge and tablets stay at room temperature. [1], [3], [4]

[3], [58], [59], [1], [11], [41], [12], [73], [4], [14], [74]

Never freeze a pen or use one that has frozen, and keep pens away from heat and light, with the cap on or in the carton. The labels say to throw away a Wegovy pen that has been above 30 °C or out of the fridge for longer than its limit. [1], [3] Unopened 7.2 mg pens have a shelf life of 3 years in the EU and 2 years in the UK; the expiry date on the pack is what counts. [11], [12]

Compounded and "research" vials. No approved label covers them, so they have no tested storage period. The FDA has reported compounded GLP-1 products arriving warm, and in 2026 it warned against using compounded multidose vials for too long. US pharmacy standards generally cap a punctured multidose vial at 28 days, a general rule rather than a semaglutide test, and sellers' claims of 28 to 60 days after mixing (reconstitution) have no published testing behind them. Laboratory tests show semaglutide breaks down faster with heat and at some acidity levels, but they set no use-by date. [5], [75], [76], [77], [78], [79], [80]

This guide does not cover pen technique or mixing; the Academy note below covers practical handling.

What does semaglutide's one-week half-life mean?

Half-life is the time it takes for the level in the blood to fall by half. For semaglutide it is about one week, which is why one injection a week is enough. With weekly doses, levels build up and then level off (steady state) after about 4 to 5 weeks. [1], [3]

It also explains two practical things. Semaglutide stays in the body for about 5 to 7 weeks after the last dose, which is why the label says to stop at least 2 months before a planned pregnancy. And after an overdose, the label advises a long period of observation, because the drug keeps acting for days. [1]

A long half-life does not mean the effect lasts: weight tends to return after stopping. [9]

What do we actually know about semaglutide in people?

A lot. Semaglutide has been tested in tens of thousands of people in large randomized controlled trials, where people are assigned by chance to the medicine or a placebo. The trial registry ClinicalTrials.gov lists 95 phase 3 trial records involving semaglutide sponsored by its manufacturer. The questions they answer are more specific than "does it work": how much weight, in whom, at which dose, for how long, and what happens after stopping. [81], [27], [82], [35]

How much weight do people lose in trials?

An average hides a wide range. In STEP 1, 86% of people on semaglutide lost at least 5% of their weight and about half lost 15% or more, while roughly 1 in 7 lost less than 5%. In the SELECT trial, which followed people for 4 years, weight loss continued for about 65 weeks and then held steady at about 10% below the starting point. [23], [87]

Most of these trials used the "treatment policy" approach, which counts everyone who was assigned to the drug, including people who stopped taking it. That makes the averages closer to real life than a count of only the people who took every dose. [23], [39]

Does it lower heart attack and stroke risk?

Yes, in the populations tested. In SELECT, 17,604 adults with heart disease and excess weight but no diabetes took 2.4 mg weekly or placebo for about 3 years. A heart attack, stroke or heart death happened to 6.5% of the semaglutide group and 8.0% of the placebo group, a 20% lower relative risk. [27], [1]

Diabetes trials point the same way: 6.6% versus 8.9% with weekly injections in SUSTAIN 6, and 12.0% versus 13.8% with daily tablets in SOUL. The label says the mechanism behind the heart benefit has not been established. [88], [82], [1]

Does it help kidneys, the liver or heart failure?

• Kidneys. In FLOW, adults with type 2 diabetes and kidney disease on 1 mg weekly had a 24% lower risk of major kidney events or heart death (331 versus 410 events). [28]
• Liver (MASH). In ESSENCE, liver inflammation cleared without worse scarring in 62.9% on 2.4 mg versus 34.3% on placebo after 72 weeks. That is a biopsy result, not yet proof of fewer liver failures. [30]
• Heart failure. In adults with a stiff-heart type of heart failure (preserved ejection fraction) and obesity, symptom and activity scores improved by 16.6 points versus 8.7 on placebo. [31]
• Knee arthritis and leg-artery disease. Knee pain scores fell by 41.7 versus 27.5 points in STEP 9; walking distance improved in STRIDE. [32], [33]

Is the weight lost fat or muscle?

Mostly fat, but lean tissue fell too. A conference abstract reported body scans from 140 STEP 1 participants, an exploratory subgroup. On semaglutide, fat mass fell by 19.3% and lean mass (everything that is not fat or bone, including muscle, organs and water) fell by 9.7% over 68 weeks. Because fat fell faster, the share of the body made up of lean mass rose by 3 percentage points. [89]

Lean mass is not the same as muscle strength. In one observational study of 106 people on 2.4 mg, handgrip strength improved over a year even though lean mass dropped early on. [90] In community education groups, strength training and enough protein are the standard advice for protecting muscle during large weight loss.

Animal studies point the same way. In obese mice, muscle size and strength fell about as much as with an equal cut in food, and recovered after the drug stopped; in obese minipigs, semaglutide kept more lean mass than dieting alone. Bone results in mice conflict; for people, see the fracture finding under label risks. The research library has the details. [91], [92]

Does it help alcohol use or Alzheimer's disease?

Alcohol use is an active research area. In a 26-week trial of 108 adults with alcohol use disorder and obesity, heavy-drinking days fell by 41.1 percentage points on semaglutide versus 26.4 on placebo, alongside talk therapy. An earlier 9-week trial in 48 adults who were not seeking treatment, using lower doses (0.25 to 1 mg a week), found less alcohol consumed in a laboratory drinking session and fewer drinks per drinking day. Semaglutide is not approved for alcohol use. [34], [93]

Alzheimer's disease is a clear negative. Two large trials, EVOKE and EVOKE+, gave semaglutide tablets (up to 14 mg a day) or placebo to 3,808 people with early Alzheimer's disease for 2 years. Memory and thinking scores declined the same in both groups. [35] Two mouse studies had reported better memory and less of the protein build-up linked to Alzheimer's in mice bred to develop it, while a third found no change in plaques or memory. The human trials are a reminder that brain benefits in animals need testing in people. [94], [95], [96]

How does semaglutide work?

Semaglutide shares 94% of its amino-acid sequence with human GLP-1 and switches on the same receptor, the GLP-1 receptor. Its effects in people are well measured: it lowers appetite and calorie intake, raises insulin and lowers glucagon (a hormone that raises blood sugar) only when blood sugar is high, and slows how fast the stomach empties. [1]

How does it reduce appetite?

In a 12-week human study, people on 1 mg weekly ate about 24% fewer calories over a day of unlimited test meals than they did on placebo. [97]

In rodents, semaglutide reached appetite areas in the brainstem and hypothalamus through a few "leaky" spots in the brain's protective barrier, rather than crossing into the whole brain. From there it changed activity in circuits that end meals. That is an animal finding about where it acts, not a measurement in people. [98]

Later mouse studies pointed to nerve cells in the area postrema, a small brainstem area that also triggers nausea, and a neighboring brainstem area. Destroying one group of cells spanning both areas largely reversed semaglutide's effects on food intake and weight, and blocking a signal inside area postrema cells stopped its weight loss. In a third mouse study, food intake still fell when the nausea-like avoidance circuit was switched off, which suggests fullness and nausea travel on partly separate paths. These are mouse findings; the human pathway has not been mapped this way. [99], [100], [101]

Does it slow the stomach?

It does, but how much that matters over time is debated. The label states that semaglutide delays stomach emptying, which is why it carries a warning for anesthesia. In one human study at 2.4 mg, an indirect drug-absorption test found no sign of slower stomach emptying at week 20 once body weight was taken into account, even though appetite and food intake were lower. The study did not measure how much of the appetite effect comes from the brain. [1], [102]

Why does one dose last a week?

A changed amino acid at position 8 stops DPP-4, the enzyme that quickly breaks down natural GLP-1, from cutting it, and the fatty-acid side chain makes more than 99% of it bind to albumin, which protects it from breakdown and from removal by the kidneys. [1], [103]

What are the risks and unanswered questions?

Is semaglutide safe?

Semaglutide has a well-studied safety profile from large, long trials: stomach and bowel side effects are common, and serious problems such as pancreatitis and gallbladder disease are uncommon but real. Its label lists who should not take it and what to watch for, and those risks apply to the approved product used at labeled doses. Unapproved products add risks of their own. [1], [104]

What are the most common side effects?

Stomach and bowel symptoms. In the weight-loss trials behind the Wegovy label, 44% of people on 2.4 mg had nausea (16% on placebo), 30% diarrhea (16%), 24% vomiting (6%) and 24% constipation (11%). Headache, tiredness, indigestion, dizziness, bloating and burping were also more common. [1]

Most of these were mild to moderate, came and went, and happened mainly while the dose was being raised. In STEP 1, 4.5% of people on semaglutide stopped because of stomach side effects, compared with 0.8% on placebo. Weight loss was similar whether or not people had these side effects. [105], [23]

What serious risks are on the label?

• Thyroid tumors (boxed warning). Semaglutide caused thyroid C-cell tumors in mice and rats. Whether it does in people is unknown. It must not be used by anyone with a personal or family history of medullary thyroid cancer or the inherited condition multiple endocrine neoplasia type 2 (MEN 2). [1]
• Pancreatitis. Inflammation of the pancreas, sometimes severe. In the weight trials it was confirmed in 4 people on Wegovy and 1 on placebo. Severe stomach pain that spreads to the back needs urgent care. [1] Monkeys given semaglutide for up to a year showed no pancreas damage under the microscope, which does not rule out rare cases in people. [106] In January 2026, the UK regulator strengthened warnings across GLP-1 medicines about rare severe and fatal cases. [107]
• Gallbladder disease. Gallstones affected 1.6% on Wegovy injections versus 0.7% on placebo, and the excess persisted after accounting for weight loss. [1]
• Kidney injury from dehydration. Vomiting and diarrhea can cause fluid loss that strains the kidneys. [1]
• Low blood sugar with other diabetes medicines. The risk rises when semaglutide is combined with insulin or sulfonylureas. [1]
• Diabetic eye disease. In people with type 2 diabetes, eye complications occurred in 3.0% versus 1.8% on placebo in SUSTAIN 6, and more often in people who already had eye disease. Fast improvements in blood sugar can temporarily worsen it. [108], [1]
• Faster heart rate, allergic reactions and anesthesia. Resting heart rate rose by 1 to 4 beats per minute on average. Serious allergic reactions have been reported. Because the stomach empties more slowly, food can be inhaled into the lungs during general anesthesia or deep sedation, so tell the care team before any procedure. [1]
• Hip and pelvis fractures. In SELECT, more hip and pelvis fractures were reported on semaglutide than on placebo in women (1% versus 0.2%) and in people aged 75 and older (2.4% versus 0.6%). [1]

Can semaglutide affect eyesight?

A rare optic-nerve condition called NAION (non-arteritic anterior ischemic optic neuropathy) causes sudden, painless vision loss in one eye. In 2025, European regulators concluded it is a very rare side effect of semaglutide, and EU product information lists it. The UK added the same very rare warning in February 2026. Australia's regulator issued a safety update in July 2026 saying the evidence may support a signal. The current US labels do not list it. [109], [11], [110], [111], [1]

The size of the risk is uncertain. Two observational studies reported higher risks. In Danish and Norwegian adults with type 2 diabetes, the risk was about 2.8 times higher. Among patients seen by eye-nerve specialists at one US hospital, it was about 4.3 times higher in people with type 2 diabetes and 7.6 times higher in people with overweight or obesity, based on small numbers of cases. Two 2026 pooled analyses of largely the same observational studies disagree: one found about 1.6 times the risk, with a range that included no increase, and rated the evidence low certainty; the other found about 2.5 times the risk and rated the evidence low to moderate certainty. Anyone with sudden vision loss should get emergency eye care. [112], [113], [114], [115]

Does semaglutide affect mood or cause suicidal thoughts?

The current evidence does not show that it causes suicidal thoughts. After reviewing 91 placebo-controlled trials with 107,910 people, the FDA found no increased risk across GLP-1 drugs and had the warning removed in January 2026; in SELECT, suicide and self-harm events were rare and equal in both groups. Some people still report feeling flat, and any mood change is worth raising with a doctor. [116], [1], [104], [117]

Does semaglutide cause thyroid cancer?

It is not known. The warning comes from rodent studies. In 2-year studies, mice and rats given semaglutide developed more thyroid C-cell tumors, including cancers; in male rats, cancers increased from blood levels below those reached in people taking Ozempic. The FDA's reviewer found that semaglutide switches on GLP-1 receptors on rat C-cells, and whether human C-cells react the same way is unknown. [118], [119]

Human studies of GLP-1 drugs as a group disagree: a French study found a higher risk of thyroid cancer, while a Scandinavian study did not. Neither was specific to semaglutide. [1], [120], [121]

Could compounded or online semaglutide change the risk?

Yes. When researchers bought semaglutide online without a prescription, only 3 of 6 orders arrived, and the samples tested were 7% to 14% pure instead of the 99% advertised; one contained bacterial toxins. The FDA had received 990 adverse-event reports for compounded semaglutide by May 2026, and it has warned about counterfeit Ozempic pens in the US supply chain. In July 2026, the UK regulator again warned against fake and illegally sold weight-loss injections, and in September 2026 the FDA updated an import alert that lets officials hold imported bulk GLP-1 ingredients without examining them. [122], [5], [123], [124], [125]

Dosing mistakes are a separate risk. A California poison-center study found that 80% of GLP-1 exposure calls were unintentional dosing errors, and most calls about compounded products involved errors in giving the dose. [126], [61]

Is semaglutide legal? Is it FDA approved?

Checked September 23, 2026. Rules differ by country and change often.

United States. Semaglutide is an FDA-approved prescription medicine. The key steps:

• 2017–2022. Ozempic injection was approved for type 2 diabetes on December 5, 2017, Rybelsus tablets on September 20, 2019, and Wegovy injection for weight management on June 4, 2021, extended to children 12 and older on December 23, 2022. [127], [128], [129], [130]
• 2024. Wegovy was approved to lower heart-attack, stroke and heart-death risk (March 8), and a new, better-absorbed tablet formulation (1.5, 4 and 9 mg) was approved in December. [131], [132]
• 2025. Ozempic gained its kidney-disease use (January 28). The FDA declared the semaglutide shortage over on February 21; pharmacies making copies under the shortage exception had to stop by April 22 or the date of a court decision (the court ruled on April 24), and outsourcing facilities by May 22. Wegovy received accelerated approval for MASH (August 15) and Wegovy tablets were approved (December 22). [133], [46], [29], [134]
• 2026. The newer tablets were renamed Ozempic tablets (January 30), the suicidal-behavior warning came off the Wegovy label (January), and Wegovy HD 7.2 mg was approved (March 19). In April, the FDA gave one generic copy of Ozempic injection tentative approval, which means it cannot be sold yet; no generic semaglutide is on sale in the US. [135], [1], [136], [137], [138]
• Salt forms and research products. The FDA says it knows of no lawful basis for compounding semaglutide sodium or acetate salts, and it has sent warning letters to sellers of "research use only" semaglutide. [5], [139], [140]

Canada. Ozempic, Rybelsus and Wegovy are prescription drugs. In April and May 2026, Health Canada approved the first generic versions of semaglutide injection, making Canada the first G7 country to do so. More have followed, including Aspen (July) and Sandoz (September). Canada's current Wegovy monograph (December 2025) stops at 2.4 mg. [58], [141], [41], [142], [143], [144], [145]

European Union. Ozempic, Rybelsus and Wegovy are authorized prescription medicines. Wegovy includes the 7.2 mg option for adults with a starting BMI of 30 or more, and a separate brand, Kayshild, has conditional approval for MASH in adults with moderate to advanced liver scarring but no cirrhosis, using weekly steps up to a 2.4 mg maintenance dose. [109], [11], [14], [21], [146]

United Kingdom. Wegovy, including 7.2 mg for adults, is a prescription medicine. The medicines regulator warns against buying weight-loss injections online without a prescription. [12], [147]

Australia. Ozempic, Wegovy and Rybelsus are registered medicines, and semaglutide is a Schedule 4 (prescription-only) medicine. Pharmacies have not been allowed to compound GLP-1 medicines since October 1, 2024. [148], [149], [150], [151], [152]

Elsewhere. Brazil registered a synthetic semaglutide pen in 2026 that it describes as a new product rather than a generic, followed by five more pens. [153], [154] In China, a drugmaker's filing dated September 8, 2026 stated that no Chinese-made semaglutide injection had been approved yet; its own application had been accepted for review. [155] A "research use only" label does not make any product legal or approved.

Is semaglutide banned in sport? Does it show up on a drug test?

It is not banned. Semaglutide is not on the World Anti-Doping Agency's 2026 Prohibited List. Markers of semaglutide are on WADA's 2026 Monitoring Program, which tracks use of substances in and out of competition without banning them. USADA gives athletes the same answer. WADA's 2027 lists, published in September 2026, keep semaglutide and tirzepatide on the Monitoring Program and off the Prohibited List. [156], [157], [158], [159], [160]

Detecting it takes a specialized laboratory test, which is how anti-doping monitoring works. Most such tests use blood; a urine test that looks for two of semaglutide's breakdown products was published in 2025. [161]

Who should be especially cautious?

• Pregnancy and breastfeeding. Stop at least 2 months before a planned pregnancy. In rats, semaglutide caused major birth defects at blood levels like those in people. Rabbit and monkey studies also found pregnancy loss or effects on the fetus, alongside marked weight loss in the mothers. Breastfeeding is not recommended with Wegovy tablets. In a human milk study, semaglutide itself was too low to measure, but the tablets' absorption helper (SNAC) or its breakdown products were present. For the injection, there are no data on human breast milk, although semaglutide does pass into rat milk. [1], [162], [163], [164]
• Thyroid cancer history. Medullary thyroid cancer or MEN 2 in you or your family rules it out. [1]
• Past pancreatitis, gallbladder disease or severe gastroparesis. These conditions need extra care, and Wegovy is not recommended with severe gastroparesis (a stomach that empties very slowly). [1]
• Diabetic eye disease or kidney problems. Eyes and kidney function need monitoring. [1]
• Under 18. Wegovy injection is approved from age 12 for obesity; Wegovy tablets are not approved for children. [1]
• Upcoming surgery or sedation. Tell the care team you take it. Guidance from US anesthesia, gastroenterology and surgery societies (2024) says most people can keep taking it, sometimes with a liquid-only diet for 24 hours beforehand; people at higher risk, such as those still stepping up the dose or with stomach symptoms, may be asked to hold a weekly dose for a week. [1], [165]
• People taking other medicines, especially insulin, sulfonylureas or thyroid medicine; see the next question.

Can semaglutide be taken with other medicines?

It depends on the medicine, and several interactions are known. [1]

• Insulin and sulfonylureas: higher risk of low blood sugar; the label advises considering a lower dose of these when semaglutide starts.
• Other pills: slower stomach emptying can change how they are absorbed. With semaglutide tablets, levothyroxine (a thyroid medicine) levels rose by 33%.
• Other GLP-1 medicines: semaglutide should not be combined with other semaglutide products or other GLP-1 receptor agonist medicines, such as liraglutide.

A combination of semaglutide with cagrilintide (CagriSema) is still being studied as a single product. Bring a full list of everything you take, including supplements, to a pharmacist or doctor. [166]

What should be monitored while using semaglutide?

Because semaglutide is an approved medicine, its labels tell prescribers what to watch. They do not set one blood-test schedule for everyone; most checks depend on your other conditions, your other medicines and any symptoms. Use this summary to prepare questions for your prescriber; it is not a personal testing plan. [1], [3], [141]

What do the labels ask prescribers to check?

[1], [3], [4], [58], [141], [14], [11], [111], [41], [59], [12]

What did the trials measure?

Beyond weight, the large trials tracked waist size, blood pressure, pulse, HbA1c, fasting blood sugar, blood fats (lipids) and C-reactive protein (CRP, a marker of inflammation). STEP 5 also tracked two pancreas enzymes (amylase and lipase) and calcitonin, a thyroid marker. SELECT and FLOW followed kidney function through eGFR (an estimate of how well the kidneys filter) and protein in the urine, and ESSENCE used liver biopsies. [23], [84], [27], [28], [30]

How is the response judged?

US diabetes standards (American Diabetes Association, 2026) advise checking an obesity medicine's benefits and safety at least monthly for 3 months, then at least every 3 months, and reconsidering it if weight loss is under about 5% after 3 months. In England, NICE guidance says to consider stopping semaglutide if less than 5% of starting weight has been lost after 6 months, and limits its use within a specialist weight service to 2 years. [167], [168]

Weight is only one outcome. People often care more about blood sugar, energy, joint pain, eating patterns or walking further, and trials measure these separately. Tracking the outcomes that matter to you, alongside dose changes and side effects, makes a conversation with your prescriber more useful.

What do people in public communities report?

Public forums contain big successes, slow progress, stalls, side effects that made people stop, and weight that came back. The most useful posts give the product, the dose in milligrams and what happened later. Discussions in community education groups are summarized here without identifying anyone.

What do the positive reports look like?

The strongest accounts describe large changes alongside other health gains. A person on 1 mg of Ozempic described losing 50 lb and coming off insulin, other diabetes pills and blood-pressure medicine, though hunger was still hard to manage. Another person with type 2 diabetes reported an 80 lb loss on up to 2 mg and an HbA1c of 5.0%. [169], [170]

Public posts describe "food noise" fading, and one person said they no longer wanted takeaway food or alcohol. [171], [172] In community education groups, members often describe "food noise" as the first thing to change; some also describe drinking less alcohol.

How long do results take, and do they last?

Slowly, and often with plateaus. One person logged every dose for 3 months while stepping from 0.25 to 1 mg and lost about 7 lb from 245 lb. Another lost 45 lb, then hit a plateau around month 8. [22], [173] In community education groups, about a dozen members described losing steadily for 6 to 24 months and then stalling, and most of them later switched to another medicine.

Does everyone lose weight?

No. Several people described months at 2.4 mg with no weight loss and no change in appetite, including one who stayed at the same weight for a year. One of them reported a sudden 5 lb drop after months of nothing, with no obvious change in routine. [174], [175], [176]

Public posts show muddying factors, such as a vial dosed in "units" of unknown strength, and in one diabetes thread weight did not move on 1 mg but blood sugar did. [177], [178] In community education groups, several members gave up after 2 to 3 months at the lowest doses, before reaching a full dose, and others had used products bought online or blends with added ingredients.

What do people report on 7.2 mg and on the tablets?

The first 7.2 mg reports are mixed: some describe appetite control and weight loss returning after months stuck at 2.4 mg, others no change or gain. Several describe skin that hurt to the touch or felt prickly, matching the label's most distinctive 7.2 mg side effect. [171], [179], [180], [181]

Tablet accounts vary. One person noticed little at 1.5 mg and fewer cravings at 4 mg; another saw no results until 9 mg; a third lost weight steadily on 4 mg. Some who switched from injections lost nothing more on tablets, or felt the effect fade within weeks. One person on 25 mg took tablets every other day for a week because of nausea and vomiting, which is not a tested schedule. [182], [183], [184], [185], [186]

What about unwanted effects?

Stomach and bowel symptoms dominate: nausea, vomiting, constipation alternating with diarrhea, reflux and tiredness. Some said nausea eased by the third week or with an anti-nausea prescription. [187], [57], [188], [189], [190] In community education groups, stomach side effects were the most common reason people stopped or switched, and sulfur-smelling burps and morning reflux came up repeatedly.

Serious reports also appear. People described hospital stays for pancreatitis, gallstones and gallbladder inflammation, and a gastroparesis diagnosis after years of treatment. Others described losing enjoyment in things while on Wegovy that returned after stopping. These are real experiences, but a forum post cannot show whether semaglutide caused them or how often they happen; the risks section gives the trial rates. [191], [192], [193], [194], [117]

What happens after people stop?

Stories run from full regain to none: one person regained all 70 lb they had lost, another about 8 lb of 116 lb, and a third kept the weight off. [195], [196], [197] In community education groups, most stops were forced by surgery, injury or lost insurance, and most of those members described regain.

Do people combine semaglutide with other drugs?

The labels say not to combine semaglutide with another GLP-1 medicine. [1] Educators in the community education groups we reviewed agree, yet a few members added small semaglutide doses to retatrutide, an experimental drug. Many switched to tirzepatide and often preferred it, but they judged it after already losing weight on semaglutide, which makes a fair comparison hard.

Are unit mix-ups common?

Yes, where vials are involved. One person injected "70 units" of a research vial without knowing the milligram dose and felt nothing. [177] In community education groups, conversion mistakes came up too: one would have halved every dose, and another, after a change of vial strength, would have meant about five times the previous dose, with nobody catching it.

How can you judge a weight-loss story?

Ask: Which product was it: brand, compounded or research? What was the dose in milligrams, not units? How long at each step? What else changed, such as diet, exercise, other medicines or menopause? What happened a year later, and after stopping?

These selected discussions show what people experience and the questions research should answer. They are not a survey of all users, a success rate or a substitute for the trials.

How does semaglutide compare with tirzepatide, retatrutide, orforglipron and CagriSema?

These are the medicines most often weighed against semaglutide. All of them act on GLP-1 signaling, but they differ in which other hormone signals they copy, how they are taken and how far they have got through testing. Status was checked on September 23, 2026.

The weight results come from separate trials in different people, so the table cannot rank these medicines. Two trials compared a medicine directly with semaglutide: SURMOUNT-5 found more weight loss with tirzepatide (20.2% versus 13.7% at 72 weeks), and REDEFINE 1 found more with CagriSema (20.4% versus 14.9% at 68 weeks). Semaglutide's heart and kidney benefits come from its own outcome trials, and those results do not carry over to the other medicines. The labels say not to combine semaglutide with another GLP-1 medicine; CagriSema has been tested only as its own product. [214], [27], [28], [1], [166]

Common questions about semaglutide

How long does semaglutide take to work?

Weight loss builds slowly. The dose takes 16 weeks to reach 2.4 mg, and in the SELECT trial average weight kept falling for about 65 weeks before leveling off. [1], [87] Some public accounts describe appetite changing within the first weeks, but the trials cited here did not measure when people first notice a change. [182] See what people report over time.

How do I manage nausea on semaglutide?

Nausea is most common while the dose is rising, and bouts are usually short: in the trials behind Canada's Wegovy label, a typical bout of nausea lasted about 8 days, vomiting 2 days and diarrhea 3 days, while constipation lasted longer, about 47 days. If a step is hard to tolerate, the Wegovy label lets the prescriber wait another 4 weeks before the next increase, and 1.7 mg is an approved long-term dose. Vomiting or diarrhea that stops you keeping fluids down needs medical advice, because dehydration can harm the kidneys. [13], [1] In community education groups, people said smaller meals, not eating close to bedtime and holding or lowering the dose helped with reflux and sulfur-smelling burps; these tips have not been tested in trials. See the most common side effects.

Is Ozempic the same as Wegovy?

Same medicine, different products. Both contain semaglutide in a weekly pen, but Ozempic is approved for type 2 diabetes with doses up to 2 mg, while Wegovy is approved for weight loss and heart-risk reduction with doses up to 2.4 mg, or 7.2 mg for some adults. [3], [1] See the dose table.

Can you take semaglutide as a pill?

Yes. Rybelsus and Ozempic tablets are approved for type 2 diabetes, and Wegovy tablets (up to 25 mg a day) for weight loss. Tablets must be taken on an empty stomach with a little water, 30 minutes before eating. In OASIS 4, the 25 mg tablet led to 13.6% average weight loss over 64 weeks. [4], [1], [86] See tablets versus injections.

What happens if you stop taking semaglutide?

Much of the weight usually comes back. In the STEP 1 extension, the group regained about two-thirds of its lost weight within a year, though it still ended about 5.6% below where it started, and improvements in blood pressure and blood sugar faded. [9] See what happens when you stop.

Is compounded semaglutide the same as Ozempic or Wegovy?

No. Compounded products are not FDA approved and are not checked for safety, quality or effectiveness the way brand products are. The FDA says the shortage exception for routine copies ended in 2025, and it knows of no lawful basis for compounding the salt forms some pharmacies used. Concentrations vary, which is how unit-based dosing errors happen. [5], [46], [61] See product quality.

Is there a generic Ozempic or semaglutide?

Not in the US yet. In April 2026, the FDA gave one generic copy of Ozempic injection tentative approval, which means it cannot be sold yet. No generic semaglutide is on sale in the US. [137], [138] Canada approved its first generic semaglutide injections in April and May 2026, and more have followed. [142], [143], [144], [145] Compounded products and "research" vials are not generics, because they are not FDA approved. [5] See legal status by country.

Can you switch from semaglutide to tirzepatide?

Yes, with a prescriber, but there is no milligram conversion between them because they are different drugs. In a head-to-head trial, tirzepatide led to more weight loss than semaglutide (20.2% versus 13.7% at 72 weeks). [214] That trial did not test switching. In community education groups, people usually restart tirzepatide at its lowest starting dose. Read the tirzepatide guide.

Glossary

Plain explanations of the medical, dosing and research terms used in this guide. Underlined terms in the text link here.

Adverse event

A harmful or unwanted medical event reported after someone used a treatment. A report alone does not prove the treatment caused it.

Albumin

The most common protein in blood plasma. Semaglutide's fatty-acid side chain makes it bind to albumin, which protects it and makes it last longer.

Amylin

A hormone released with insulin after meals that helps signal fullness. Cagrilintide is a long-acting lab-made version.

Animal study

Research in animals such as mice, rats, pigs or monkeys. It shows what a substance does in a living body, but results in people can differ.

Area postrema

A small area in the brainstem where the brain's protective barrier is leaky, so it can sense substances in the blood. It is involved in nausea and in ending meals.

Bioavailability

How much of a dose reaches the bloodstream in a usable form. For semaglutide it is 89% by injection, about 0.4% to 1% for Rybelsus tablets and about 1% to 2% for Ozempic and Wegovy tablets.

BMI (body mass index)

Weight in kilograms divided by height in meters squared. A BMI of 30 or more is classed as obesity in adults.

Boxed warning

The most serious type of warning on a US drug label, printed in a box at the top. Semaglutide's is about thyroid tumors seen in rodents.

C-cells (thyroid)

Cells in the thyroid gland that make the hormone calcitonin. Medullary thyroid cancer starts in these cells.

Cell study (in vitro)

Research on cells or tissue grown in a dish. It gives early clues about biology, but it is far from proof of benefit in people.

Compounding

When a pharmacy prepares a customized medicine from individual ingredients. Compounded drugs are not FDA approved.

Course and cycle

A course is a period of repeated use. A cycle is a course plus a planned break. Semaglutide labels describe continuous use, not cycles.

Dose (amount each time)

The amount given on one occasion. For weekly semaglutide injections, the dose is also the weekly total.

Dysesthesia

Unusual or unpleasant skin sensations such as tingling, burning or pain from light touch. It is more common at the 7.2 mg dose.

Gastric emptying

How quickly food leaves the stomach for the intestine. Semaglutide slows it.

GIP (glucose-dependent insulinotropic polypeptide)

Another gut hormone released after eating that boosts insulin. Tirzepatide and retatrutide switch on its receptor as well as the GLP-1 receptor; semaglutide does not.

GLP-1 (glucagon-like peptide-1)

A hormone released by the gut after eating. It raises insulin when blood sugar is high, lowers glucagon, slows the stomach and signals fullness to the brain.

GLP-1 receptor agonist

A medicine that switches on the GLP-1 receptor, copying the hormone's effects. Semaglutide, liraglutide and dulaglutide are examples.

Half-life

The time it takes for the level of a substance in the blood to fall by half. For semaglutide it is about one week.

HbA1c

A blood test that reflects average blood sugar over roughly the past three months. It is the main measure of diabetes control.

Hypoglycemia

Blood sugar that is too low. It can cause shakiness, sweating and confusion, and is more likely when semaglutide is combined with insulin or sulfonylureas.

INR (international normalized ratio)

A blood test showing how long blood takes to clot. It is used to adjust warfarin, a blood thinner.

Intraperitoneal

Given into the abdominal cavity. It is a common route in animal studies; in people it is used only for a few specialized treatments, and never for semaglutide.

Lean mass

Everything in the body that is not fat or bone, including muscle, organs and water. A body scan measures it; it is not the same as muscle strength.

Maintenance dose

The dose a person stays on after the step-up period ends. For Wegovy injection it is usually 2.4 mg a week.

MASH

Metabolic dysfunction-associated steatohepatitis: fatty liver disease with inflammation and scarring, formerly called NASH.

Microdosing

An informal term for taking less than a standard dose. For semaglutide it has no agreed meaning and has not been tested in trials.

Milligram (mg)

A thousandth of a gram. Semaglutide doses are written in mg; 1 mg equals 1,000 micrograms (mcg).

NAION

Non-arteritic anterior ischemic optic neuropathy: sudden, usually painless vision loss in one eye caused by reduced blood flow to the optic nerve.

Oral

Taken by mouth and swallowed, as a tablet.

Pancreatitis

Inflammation of the pancreas. It causes severe upper stomach pain, often spreading to the back, and needs urgent care.

Peptide

A short chain of amino acids. Semaglutide is a chain of 31 with a fatty-acid side chain attached.

Pharmacokinetics

How the body absorbs, moves, breaks down and removes a substance.

Placebo

A dummy treatment with no active ingredient, used as a comparison in studies.

Preclinical research

Cell and animal studies of how a substance works and what harm it might cause, including the safety tests regulators require. Many are done before research in people, and some continue alongside human trials.

Prescription-only (Schedule 4)

A medicine that can only be supplied with a prescription. In Australia this category is called Schedule 4.

Randomized controlled trial

A study that assigns people by chance to a treatment or a comparison, often a placebo, so the groups can be compared fairly.

Reconstitution

Mixing a freeze-dried powder with a liquid so it can be measured and injected. The amount of liquid sets how much drug each unit holds. Approved semaglutide pens need no mixing.

SNAC (salcaprozate sodium)

An absorption helper in semaglutide tablets. Laboratory and animal studies suggest it briefly protects semaglutide in the stomach and helps it cross the stomach lining.

Steady state

The point at which levels in the blood stop building up because the amount taken matches the amount removed. With weekly semaglutide it takes about 4 to 5 weeks.

Subcutaneous (SC)

Injected into the fatty layer just under the skin. Semaglutide pens inject into the belly, thigh or upper arm.

Sublingual

Placed under the tongue to dissolve rather than swallowed. No sublingual form of semaglutide is approved.

Syringe units

Markings on an insulin syringe that measure volume. On a U-100 syringe, 100 units equal 1 mL. The amount of drug per unit depends on the vial's concentration.

Tapering

Lowering a dose in steps before stopping. No completed trial has tested whether tapering off semaglutide limits weight regain.

Titration

Adjusting a dose in steps, usually starting low and increasing. Semaglutide labels raise the dose every 4 weeks.

Treatment policy

A way of analyzing a trial that counts everyone assigned to a treatment, including people who stopped taking it.

Type 2 diabetes

A long-term condition in which the body does not use insulin well, so blood sugar runs too high.

WADA

The World Anti-Doping Agency, which publishes the list of substances banned in sport and a separate Monitoring Program of substances it tracks without banning.

Explore more of the research

Go deeper into the animal experiments and regulator safety reviews behind the claims.

Across this guide, the citations include 79 original research papers: 47 human studies and 32 cell and animal studies. The optional library below explores 30 of the animal papers and 6 FDA and European reviews of the manufacturer's animal safety tests, organized by question. Paper counts are not counts of independent research teams: some studies share authors, methods or funders, and several were done by the manufacturer. Preclinical results show what happened in animals; they are not proof of the same effect in people, and animal doses are never converted to human doses here.

In the route details, intraperitoneal means injected into the abdominal cavity and subcutaneous means into the fatty layer under the skin.

How this guide was researched

This guide is built from a thorough review of the sources cited throughout it: product labels from several countries, published clinical trials and studies, clinical-trial registry records, regulatory documents and published dosing descriptions. We also reviewed public online forums and community education groups where people describe their own experiences with semaglutide.

The guide cites 236 sources, including 79 original research papers on people, cells or animals (47 human studies and 32 cell and animal studies), plus laboratory papers on stability, product quality and drug testing. Each type of source answers a different question. Labels and trials show what was approved and measured. Dosing descriptions show how semaglutide is typically discussed and used. Personal accounts show what individual people experienced. Every numbered citation links to its entry below, labeled by source type. The research library above summarizes the animal studies and regulator safety reviews by question.

How this guide was made

Research and drafting were AI-assisted. Every cited source was checked against the original, and the guide was reviewed and edited by Doserly before publication. It has not had an independent clinical review, and Doserly does not currently have medical reviewers. Doserly makes a medication and health-tracking app and runs Doserly Academy, both of which are promoted in this guide. Read our editorial policy for how guides are researched, updated and corrected.

This guide is for educational purposes. It summarizes what the reviewed sources report so the research is easier to understand; it is not medical advice. For a deeper dive, or to check any point for yourself, go straight to the cited sources.

Explore the sources