TRT and Sexual Health: The Definitive Guide

What does testosterone do for sex, and what can TRT change?

Testosterone is one of several things behind a man's libido (sex drive) and, to a smaller degree, his erections. When testosterone is genuinely low, the sexual symptoms that show up most are low desire, fewer morning erections and erectile dysfunction (ED), meaning trouble getting or keeping an erection firm enough for sex. In men with confirmed low testosterone, testosterone therapy (TRT) improves desire and sexual activity fairly reliably, and erections modestly. [1], [2], [3], [4]

Desire and erections run on different systems. Desire starts in the brain. An erection is a blood-flow event: nerves signal the blood vessels in the penis to relax and fill, which depends on healthy arteries and nerves as much as on hormones. That is why TRT often restores wanting sex without always fixing erections, and why the ED tablets, PDE5 inhibitors such as sildenafil (Viagra) and tadalafil (Cialis), remain the main ED treatment. [11], [14]

Low testosterone (hypogonadism) is also not the usual cause of ED. In 1,022 men referred for ED, repeatedly low testosterone was found in 4% of men under 50 and 9% of men 50 or older, and 40% of first low results were normal on a repeat test. The European Association of Urology (EAU) estimates that about 30% of men with ED also have low testosterone, a figure that depends on the cut-off used. [21], [8]

TRT and sexual health: the key numbers

This table shows what each major clinical guideline says about testosterone and sexual symptoms: the level it treats as low, who it tests, what it says treatment does for sex, and when it judges the response. Checked September 2026.

[6], [10], [7], [22], [8], [23], [11], [13], [12], [15], [14], [24], [25], [18]

The guidelines agree that testosterone helps sex only when testosterone is genuinely low, and the trials behind them show desire responding more reliably than erections. The low-testosterone line varies from 264–300 ng/dL in US documents to 12 nmol/L (about 350 ng/dL) in European and international ones. The British sexual-medicine and UK endocrine bodies see the clearest erection benefit below 8 nmol/L (about 230 ng/dL). The main disagreement is about combining testosterone with an ED tablet, covered in what guidelines do. [7], [8], [2], [13], [15]

Why do the thresholds differ?

Partly because of how testosterone is measured and partly because of who was studied. The Endocrine Society's 264 ng/dL is the lower limit of normal in healthy young men measured with a standardized, certified assay. The AUA picked 300 ng/dL as a practical cut-off. The EAU and ICSM treat 12 nmol/L as a reliable line for diagnosing low testosterone that appears in middle and older age. [7], [6], [8]

Sexual symptoms do not switch on at one number. In the European Male Ageing Study of 3,369 men aged 40 to 79, only the three sexual symptoms (poor morning erections, low desire and ED) formed a clear pattern with low testosterone. Their likelihood rose across a band from 8 to 13 nmol/L. The study's research definition of late-onset hypogonadism (low testosterone that appears with age) needs at least three sexual symptoms plus total testosterone below 11 nmol/L (about 320 ng/dL) and free testosterone below 220 pmol/L. It is a research definition, not a treatment rule. [1], [15]

Desire and erections also respond at different levels. In 434 men aged 50 to 86, loss of libido became more common below 15 nmol/L, while ED was linked to testosterone only below 8 nmol/L. The ICSM reports that each 1 nmol/L drop below 8 nmol/L raised the risk of low desire by 48%. [26], [11]

How do the units work?

US labs report testosterone in ng/dL; most other countries use nmol/L. 1 nmol/L is about 28.8 ng/dL, so 12 nmol/L is about 346 ng/dL (often rounded to 350) and 8 nmol/L is about 231 ng/dL. Free testosterone, the small share not bound to proteins, is reported in pmol/L or pg/mL: 220 pmol/L is about 64 pg/mL. The testosterone unit converter switches between them, and the TRT blood work guide explains when to draw each test. [1]

How does testosterone affect desire, erections and orgasm?

Testosterone acts in the brain, where desire starts, and in the tissue of the penis, where erections happen. Human studies show clearly that very low testosterone reduces desire; the effects inside the penis come mostly from laboratory and animal research. [11], [27]

• Desire. The ICSM states that testosterone "significantly contributes to the regulation of male sexual desire". In 177 men aged 60 to 80 whose own testosterone was switched off and then replaced at different levels, desire and erections held up until testosterone fell below 100 ng/dL, a very low level. [11], [27]
• Estradiol helps too. Men turn some testosterone into estradiol, the main estrogen. When men's testosterone and estradiol were lowered experimentally, both hormones contributed to lower sexual function. In the Testosterone Trials, bigger rises in estradiol as well as testosterone went with bigger gains in desire and activity. [28], [29]
• Erections. The ICSM lists testosterone's targets in penile tissue: the nitric oxide signal that relaxes smooth muscle so blood can flow in, and the upkeep of that smooth muscle. It also notes that sustained low testosterone goes with worse erections. Most of this comes from laboratory and animal work. In a small study of 8 men with normal testosterone, one testosterone injection made night-time erections more rigid but not more frequent. [11], [30]
• DHT is not the missing piece. Testosterone is partly converted to DHT. The ICSM finds DHT's effect on erections similar to testosterone's and advises against measuring it or using DHT-based products instead of testosterone. In a 20-week trial of 139 men given testosterone, blocking DHT with dutasteride did not change sexual function. [11], [31]

Does more testosterone mean better sex?

Not reliably. In healthy young men whose own testosterone was switched off and replaced at weekly research doses, sexual function did not change significantly at any dose, including the lowest doses that left testosterone below normal. Meanwhile, hemoglobin rose and HDL ("good") cholesterol fell as the dose went up. In older men given graded research doses, overall sexual function scores and waking erections rose with dose, but how often the men had intercourse or masturbated did not. These were research doses, not treatment protocols, and no trial has shown that pushing testosterone above the normal range improves sex in daily life. [16], [32]

What does the research show?

Placebo-controlled trials in men with low testosterone agree that TRT improves sexual desire and activity. Its effect on erections is real but modest, it depends on how low testosterone was to start with, and orgasm and ejaculation change little. [2], [3], [4], [33]

Does TRT improve sex drive?

Yes, most consistently of all its sexual effects. The two largest trials both found it:

A September 2026 review of the Testosterone Trials and TRAVERSE concluded that testosterone improves sexual function and mood but not energy, physical function or thinking. [37] The same pattern held after prostate cancer surgery: in a 2026 trial of 136 men treated for low-grade prostate cancer, 12 weeks of testosterone cypionate 100 mg weekly improved sexual activity and desire but not erections. That trial was too short and small to judge long-term cancer safety; see the TRT and prostate guide. [38]

Other ways of raising testosterone may help desire less. A 2026 meta-analysis found that clomiphene, a pill that makes the body produce more of its own testosterone, raised testosterone about as much as testosterone gel, but libido scores improved less than with TRT. [39] The clomiphene guide covers it in full.

Does TRT improve erections?

Modestly. Most trials measure erections with the IIEF erectile function score, which runs up to 30 points; higher is better. Pooled trials put TRT's average gain at about 2 points:

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How much testosterone raised erection scores

Average gain over placebo on the IIEF erectile function score (0–30 points; dots are averages, lines 95% ranges).

Each strip runs from 0 (left) to 9 points (right); the dashed mark is 4 points, the smallest noticeable change used by the Cochrane review.

Corona 2017, all trials: +2.31 points (95% range 1.41–3.22)

Meta-analysis, 14 trials, 2,298 men

Corona 2017, below 12 nmol/L: +1.47 points (95% range 0.90–2.03)

Same analysis, men with testosterone below 12 nmol/L

Corona 2017, below 8 nmol/L: +2.95 points (95% range 1.86–4.03)

Same analysis, men with testosterone below 8 nmol/L

Hudson 2023: +2.14 points (95% range 1.40–2.89)

Individual data, 17 trials, men below 12 nmol/L

Testosterone Trials 2016: +2.64 points

Men 65 or older, one year of gel (no range reported)

Taniguchi 2022: +1.86 points (95% range 1.01–2.72)

Meta-analysis, 6 trials, 1,458 men

Cochrane 2024: +2.37 points (95% range 1.67–3.08)

Men WITHOUT diagnosed low testosterone, 6 trials, 2,016 men

Sildenafil alone, for scale only: +7.7 points (95% range 6.5–8.8)

Separate trial (Spitzer 2012, 140 men): change from start, not vs placebo

TRAVERSE (1,161 men with low libido): no erection improvement. T4DM: a meaningful gain in 23% of men on testosterone and 20% on placebo. Hudson 2023 found its 2.14-point gain reached the smallest meaningful change for mild ED; the Cochrane review used 4 points.

What does 2 points mean? The Hudson analysis found the 2-point gain reached the smallest change that matters to men with mild ED. The Cochrane reviewers used 4 points as the smallest change men notice (the minimal clinically important difference), and by that yardstick the average gain falls short. Averages also hide a spread: the AUA panel says it cannot tell what share of men get a meaningful improvement. [5], [41], [6]

A 2024 meta-analysis of 28 trials reported a larger average, 3.26 points. Like the Cochrane review, it combined the full erection questionnaire with a shorter five-question version, so neither number is exactly comparable with the others. [42], [41]

Does it matter how low testosterone was?

Probably, though the analyses disagree. The erection gain in Corona's analysis was twice as large below 8 nmol/L (2.95 points) as below 12 nmol/L (1.47). In a trial of 199 men with type 2 diabetes, erections improved only in men whose testosterone started at or below 8 nmol/L, and only after 30 weeks. Hudson's individual-data analysis, limited to men below 12 nmol/L, found the average gain did not depend on starting testosterone, although men who started lower ended with lower scores. [4], [43], [5]

Men with normal testosterone do not benefit. A review of trials found testosterone had no effect on erections in men with normal levels. The 3-year TEAAM trial of 308 men aged 60 or older with low or low-normal testosterone found no change in desire, erections or overall sexual function. The EAU strongly advises against treating men with normal testosterone. [9], [44], [8] The Endocrine Society concludes that testosterone does not significantly improve sexual function in men who do not have low testosterone. [7]

Does diabetes or obesity blunt the effect?

The research conflicts. The trials in men with diabetes suggest the starting level matters most.

• Smaller effect: Corona's and Taniguchi's meta-analyses found smaller erection gains in men with diabetes, obesity or metabolic syndrome. [4], [40]
• No difference: Hudson's pooled individual data from 17 trials found the erection gain did not depend on age, weight or diabetes, although older men and men with obesity started worse and so ended with lower scores. [5]
• Trials in diabetes split by starting level. In 88 men with type 2 diabetes and testosterone below 12 nmol/L, 40 weeks of testosterone undecanoate injections gave no sexual benefit; the short erection score even favored placebo by 2.0 points. The BLAST study of 211 men found benefit only in men with severe deficiency (8 nmol/L or less). In T4DM, all five sexual areas improved. [45], [46], [34]

The practical reading: TRT's benefit for erections is modest at best, the trials in men with diabetes whose testosterone was only mildly low were disappointing, and weight, blood sugar and blood-vessel health matter as much. The obesity-related low testosterone guide covers weight loss first.

Does TRT help orgasm, ejaculation or semen volume?

Not clearly. In the only randomized trial in men with both low testosterone and ejaculation problems (76 men, 16 weeks of testosterone solution), ejaculation scores rose on testosterone (3.1 points) and on placebo (2.5 points), with no real difference. Measured semen volume did not differ from placebo either. [33] A larger 12-week trial of 715 men found self-reported ejaculatory function improved, but how much the problem bothered men did not. [47] The Endocrine Society concludes that testosterone does not improve ejaculatory function. [7]

For orgasm, results differ by study: Corona's meta-analysis reported improvement, the BLAST trial in diabetes found none, and T4DM found orgasm improved, more so in older men. [4], [43], [34] No controlled study has measured genital sensation on TRT.

How long does TRT take to work for sex?

Desire usually changes first, within weeks; erections take months.

• Desire. A review of treatment time courses put the first changes in sexual interest at about 3 weeks, leveling off by 6 weeks. The ICSM reports effects on libido, ejaculation and sexual activity within 2 to 3 weeks, and the Society for Endocrinology within 3 to 6 weeks. [48], [11], [15]
• Erections. The same review found erection changes could take up to 6 months, and the ICSM says 6 or even 12 months. In men with diabetes and severe deficiency, erections improved only after 30 weeks. [48], [11], [43]
• Guideline expectations. The CUA tells men to expect gains after 3 months or longer. [12]
• Staying power. In TRAVERSE, the gain in sexual activity lasted to 24 months. In the Testosterone Trials, the response was somewhat smaller at 12 months than earlier. The AUA notes long-term observational data suggesting erection improvements may continue for up to 3 years. [2], [3], [6]

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When sexual changes show on testosterone

Desire

1. 2–3 weeks

   ICSM: libido, ejaculation and activity.

2. 3–6 weeks

   Saad review: interest from about 3 weeks, level by 6.

3. 3–6 weeks

   Society for Endocrinology: sexual interest.

4. 24 months

   TRAVERSE: activity gain still present.

Erections

1. Up to 6 months

   Saad review: changes up to 6 months.

2. 6–12 months

   ICSM: can take 6 or even 12 months.

3. 30 weeks

   BLAST (diabetes): only after 30 weeks, severe deficiency.

When guidelines judge the response

1. 3 months

   CUA: stop if no gain by about 3 months; EAU first review.

2. 3–6 months

   AUA: discuss stopping at 3–6 months if no improvement.

3. 6 months

   BSSM: stop if no benefit by 6 months.

4. 6–12 months

   VA: stop if no improvement after 6–12 months.

5. 12 months

   ACP: re-evaluate within 12 months.

Each marker comes from one source; no curve is drawn between them, and individual men vary.

The TRT results timeline guide sets sexual changes beside energy, mood, muscle and red blood cells.

Does TRT help men with depression or on antidepressants?

Possibly, in one small trial. In 100 depressed men with low or low-normal testosterone taking serotonin-based antidepressants, 6 weeks of testosterone gel raised the total sexual-function score by 16.8 points more than placebo, including ejaculation. Only 63 men had complete data, and men with higher testosterone improved about as much as men with lower levels. [49] Depression itself lowers sexual function, but it did not block the benefit in T4DM. There, the gain in desire on testosterone was larger in men with more depressive symptoms, and falling depression scores went with better sexual function in both groups. [34] The TRT and mental health guide covers mood.

What research is under way?

Checked September 2026. A randomized trial of testosterone gel around prostate-removal surgery, with sexual function as its main outcome, is recruiting (140 men planned). A 20-man study of the Xyosted autoinjector for ED in multiple sclerosis was not yet recruiting, and a trial of Natesto nasal gel on erections and sexual satisfaction was withdrawn without enrolling anyone. [50], [51], [52]

Is TRT safe, and what sexual side effects can it cause?

For men with confirmed low testosterone who are monitored, TRT's main risks are not sexual: they are red blood cells, fertility, blood pressure and prostate checks. Labels list a few sexual side effects, mostly without rates, and heart safety comes from the TRAVERSE trial. [53], [7], [54], [55]

What sexual side effects do the labels list?

• Too many or too-long erections. The Depo-Testosterone label says "priapism or excessive sexual stimulation may develop", and patient information for Depo-Testosterone, AndroGel 1.62%, Xyosted and Aveed tells men to report "too frequent or persistent erections of the penis" to their prescriber. [53], [56], [57], [58]
• Changes in libido, in either direction. Labels list "increased or decreased libido". UK labels add that prolonged or frequent erections, irritability and nervousness can mean too much testosterone and a need to adjust the dose. [53], [58], [59]
• Ejaculation. In Aveed's trials, 2 men (1.3%) reported an ejaculation disorder. [58]

Labels give no rates for most of these, so they cannot say how often they happen.

Does TRT affect fertility?

Yes, and this matters for anyone planning children. Testosterone from outside the body switches off the brain's signal to the testicles, lowering sperm production. In a World Health Organization contraception trial, weekly testosterone enanthate injections left 65% of healthy men with no sperm within 6 months. Labels warn that reduced fertility can be irreversible, and the AUA says testosterone should not be prescribed to men trying to conceive. [60], [57], [6] The TRT and fertility guide and the hCG guide cover options that protect sperm production.

What did TRAVERSE show about heart safety?

TRAVERSE is the largest trial of testosterone and heart safety, and its sexual results in this guide come from the same trial. About 5,200 men aged 45 to 80 with low testosterone and heart disease or high heart risk used a daily testosterone gel or a placebo gel. Heart attack, stroke or cardiovascular death occurred in 7.0% of men on testosterone and 7.3% on placebo (182 of 2,596 men vs 190 of 2,602; hazard ratio 0.96), which met the trial's safety goal. In the same two groups, some problems were more common on testosterone: atrial fibrillation 3.5% vs 2.4%, acute kidney injury 2.3% vs 1.5%, pulmonary embolism 0.9% vs 0.5%, and other nonfatal heart-rhythm problems needing treatment 5.2% vs 3.3%. [54], [55] Clinical fractures were also more common on testosterone: 91 of 2,601 men (3.5%) vs 64 of 2,603 (2.5%), hazard ratio 1.43. [61] High-grade prostate cancer was rare in both groups, 5 of 2,596 men (0.19%) vs 3 of 2,602 (0.12%), a difference that was not significant; see the TRT and prostate guide. [62]

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TRAVERSE: absolute results

Testosterone gel (2,596 men)Placebo gel (2,602 men)

Heart attack, stroke or heart death

Testosterone 7.0% vs placebo 7.3% (182 vs 190 men; hazard ratio 0.96, 95% CI 0.78–1.17; met the 1.5 safety margin)

Nonfatal rhythm problems needing treatment

Testosterone 5.2% vs placebo 3.3%

Atrial fibrillation

Testosterone 3.5% vs placebo 2.4%

Clinical fracture

Testosterone 3.5% vs placebo 2.5% (91 of 2,601 vs 64 of 2,603 in the full analysis set)

Acute kidney injury

Testosterone 2.3% vs placebo 1.5%

Venous clots (all)

Testosterone 1.7% vs placebo 1.2%

Pulmonary embolism

Testosterone 0.9% vs placebo 0.5%

About 5,200 men aged 45–80 at high heart risk; daily gel; mean treatment 21.7 months; about 61% stopped their study gel. Not a trial of injections.

Its limits matter: it tested only a daily gel, men used it for an average of 21.7 months, about 61% stopped their study gel early, and it enrolled men already at high heart risk. [54], [55] The TRT and heart health guide covers the trial in full, and the hematocrit guide covers red blood cells.

Who should be especially cautious?

• Men trying for a pregnancy now or soon. Guidelines advise against testosterone for them (see fertility above). [6], [8]
• Men who take nitrate medicines for chest pain, such as nitroglycerin, if an ED tablet is part of the plan. Taking nitrates in any form with sildenafil or tadalafil is contraindicated because blood pressure can drop dangerously. [63], [64]
• Men with very low testosterone plus low or normal LH, or with high prolactin. These can point to a pituitary problem that needs its own work-up. The AUA advises a pituitary scan when total testosterone is below 150 ng/dL with low or low-normal LH, and the EAU when secondary low testosterone comes with high prolactin. [6], [8]
• Men with depression, or taking antidepressants or other medicines that affect sex (see the next question). [17], [49]
• Men with conditions guidelines list as reasons not to start, such as a raised hematocrit, untreated severe sleep apnea, recent heart attack or stroke, or prostate or breast cancer. [7]
• Drug-tested athletes. Testosterone is prohibited in sport at all times. [20]
• Under-18s. Testosterone for teenagers belongs only in specialist care.
• Women. This guide is written for men. Testosterone for women uses different doses and products; see testosterone therapy for women.

Which medicines affect sexual function or interact?

Several common medicines lower desire or erections on their own, which is worth checking before blaming testosterone:

• Antidepressants. On the sertraline (Zoloft) label, men in trials (1,316 on sertraline, 973 on placebo) reported ejaculation failure in 8% vs 1% on placebo, decreased libido in 7% vs 2%, and ED in 4% vs 1%. [17]
• Finasteride and dutasteride (5-alpha reductase inhibitors, for hair loss or an enlarged prostate). On the Propecia label (945 men on finasteride, 934 on placebo), decreased libido was 1.8% vs 1.3% on placebo in the first year, ED 1.3% vs 0.7%, and ejaculation disorder 1.2% vs 0.7%. Reports after approval include sexual problems that continued after stopping. On the Avodart label (2,167 men on dutasteride, 2,158 on placebo), impotence was 4.7% vs 1.7% and decreased libido 3.0% vs 1.4% in the first 6 months, falling to about placebo levels later. [65], [66]
• Opioid painkillers. Long-term opioid use lowers the body's own testosterone: a 2020 meta-analysis found low testosterone in 63% of men using opioids, and opioid labels warn of androgen deficiency with long-term use. [67], [68]
• ED tablets with nitrates. Contraindicated, as above. [63], [64]
• Aromatase inhibitors such as anastrozole. In older men with low testosterone, a year of anastrozole raised testosterone but lowered spine bone density compared with placebo. The VA does not generally recommend these medicines for men on testosterone. [69], [14]
• Supplements sold for sexual enhancement. FDA does not approve dietary supplements for safety or effectiveness and warns that male enhancement products are likely to be contaminated with dangerous hidden ingredients. [70]

Bring a complete list of what you take, including supplements, to a pharmacist or prescriber. Checked September 2026.

Is testosterone legal, and is it allowed in sport?

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

• United States. Testosterone and its esters are Schedule III controlled substances, prescription only. FDA-approved products are for men with low testosterone plus an associated medical condition; none is approved for sexual problems. On 16 April 2026 FDA invited companies that hold approved testosterone applications to seek a low-libido indication in men whose low testosterone has no identified cause. That is an invitation, and no such indication has been approved. Separately, label changes requested in June 2026 (removing the age-related limitation, among others) are still pending and not yet in any label. [19], [25], [18], [71]
• United Kingdom. Testosterone is a Class C controlled drug, in Schedule 4 Part II of the Misuse of Drugs Regulations. [72]
• Canada. Testosterone is a Schedule IV controlled substance. [73]
• Australia. Testosterone is a Schedule 4 prescription-only medicine. [74]
• Sport. The World Anti-Doping Agency (WADA) prohibits testosterone at all times, and its 2027 list, published in September 2026, keeps the ban. Aromatase inhibitors and clomiphene are prohibited too. [20], [75]

What do guidelines say to do about sexual symptoms?

Guidelines first confirm that testosterone is genuinely low, look for other causes, then treat and judge the response within months. This section describes the choices clinicians weigh; it is not a personal plan. [6], [7], [8], [11]

[10], [23], [11], [6], [12], [13], [14], [24], [15]

Should TRT be combined with tadalafil or sildenafil?

Guidelines disagree, and so do the trials.

• For combining. The AUA's ED guideline says men with ED and low testosterone should be told a PDE5 inhibitor may work better combined with testosterone. The BSSM says to consider the combination, and the EAU suggests it for more severe ED (a weak recommendation). A 2020 meta-analysis of 8 trials (913 men) found the combination beat a PDE5 inhibitor alone, with no difference in side effects or PSA. The EAU adds that men with low testosterone who do not respond to ED tablets may respond after starting testosterone. [10], [13], [8], [77], [23]
• Against. In a randomized trial of 140 men with ED and low or low-normal testosterone, adding testosterone to an optimized sildenafil dose raised the erection score by a further 2.2 points over placebo, a difference that was not statistically clear. Before randomization, sildenafil alone had already raised it by 7.7 points, a before-and-after change with no placebo comparison. In 173 men who had not responded to tadalafil, adding testosterone gel helped overall no more than placebo; the benefit was clear only in men whose testosterone started at or below 3 ng/mL (300 ng/dL). The Endocrine Society concludes that trials failed to show extra erection benefit from adding testosterone to an optimized ED tablet, and the VA keeps ED tablets first-line. [78], [79], [7], [14]

The reading most consistent with both sides: adding testosterone helps erections most in men whose testosterone is clearly low, and guidelines add or prefer an ED tablet for more severe ED. A 2014 meta-analysis also found that, after adjusting for possible publication bias, the positive effects of testosterone on erections and libido held up only in trials partly or fully funded by drug companies. Its authors thought trial design, more than bias, might explain the difference. [79], [13], [8], [14], [78], [80]

What the ED tablet labels say. Tadalafil (Cialis) for ED starts at 10 mg before sexual activity (adjustable to 5–20 mg), or 2.5 mg once daily (up to 5 mg). Sildenafil (Viagra) is usually 50 mg about an hour before sex (25–100 mg, at most once a day). Both are contraindicated with nitrates in any form. These are label doses, set by a prescriber; the TRT dosage guide covers testosterone doses themselves. [63], [64]

What happens if TRT does not help?

Most guidelines say to stop, at review points from about 3 months (CUA) to 12 months (ACP), as the tables above show. [12], [6], [13], [14], [24] No baseline trait in the Testosterone Trials predicted who would respond, so the AUA, CUA, BSSM, VA and ACP treat the first months as a trial with a clear review date. [29] The Society for Endocrinology disagrees: it does not accept a time-limited "therapeutic trial" and expects most men with a confirmed diagnosis to stay on treatment for life. [15] The stopping TRT guide covers what happens when testosterone stops.

Why can sex drive stay low on TRT?

The short answer: testosterone is only one input. Once levels are in range, most persistent problems come from something else, and the practical questions below cover the most common ones.

Why is my libido low on TRT when my levels look good?

A higher dose is not a reliable fix: dose studies found no gain in how often men had sex from more testosterone (see does more testosterone mean better sex?). [16], [32] The causes guidelines and labels name include:

• Depression, and the medicines for it (see interactions). [17], [34]
• Finasteride or dutasteride, and opioids. [65], [66], [67]
• High prolactin (see below). [11]
• Blood-vessel health and diabetes. Erections depend on healthy arteries, and trials in men with diabetes found smaller or no erection gains unless testosterone was very low. [4], [43]
• Relationship strain, stress and performance anxiety, which come up again and again in public threads (see what people report).
• Timing. Desire can take weeks and erections months, so an early verdict can mislead. [48]

The Endocrine Society's 2026 statement also stresses ruling out reversible causes such as obesity, corticosteroids and opioids before treatment. [22]

Is it estrogen? Does an aromatase inhibitor help?

Probably not, and guidelines lean against it. The ICSM advises clinicians to "consider not prescribing" aromatase inhibitors for low desire and not to measure estrogen to judge erections, and calls estrogen's role in erections "still controversial". The AUA measures estradiol only when there are breast symptoms. [11], [6] Estradiol made from testosterone supports sexual function: in the Testosterone Trials, bigger estradiol rises went with bigger gains in desire and activity. [28], [29] The only trial of anastrozole for sexual function on TRT, in 40 men with epilepsy, found sexual function normalized in 72.2% with anastrozole plus testosterone and 47.4% with placebo plus testosterone, a difference that was not significant. [76] The estrogen on TRT guide covers estradiol in full.

Could prolactin be the cause?

Occasionally. Prolactin is a pituitary hormone; very high levels suppress desire and testosterone. The ICSM advises measuring prolactin in every man with low desire and reports severe high prolactin in 1.4% of men seeking care for low libido. It links levels above 35 ng/mL with a more than tenfold higher chance of low desire. Mild rises are unlikely to explain low desire. In an older study of 1,821 men with ED, prolactin was above 20 ng/mL in 1.86%. [11], [21] Cabergoline, a medicine that lowers prolactin, is approved for high-prolactin disorders; treating a severe rise waits until its cause is known. [81], [11] Several common medicines, including some antidepressants, opioids and antipsychotics, can raise prolactin. [6]

Do injections make libido swing?

Some men notice it, and guidelines list it. The Endocrine Society lists "fluctuation in mood or libido" as a side effect of intramuscular (into a muscle) injections, and the BSSM notes changes in mood, energy and sexual desire with injections. [7], [13] No trial has tested whether more frequent injections steady sexual function. The testosterone level visualizer shows how injection frequency changes the peaks and troughs, and the TRT dosage guide covers split schedules.

Can TRT make libido too high?

It can rise more than a partner expects. Labels list increased libido and "excessive sexual stimulation", and UK labels say prolonged or frequent erections can signal too much testosterone and a need to adjust the dose; tell your prescriber. [53], [59] Public threads describe early surges that settle and desire mismatches with partners (see what people report).

Does TRT change orgasm, semen volume or sensation?

Not reliably, in either direction (see the research). The one trial that measured semen volume found no difference from placebo. [33] Other medicines can play a part: finasteride's label lists decreased ejaculate volume, and dutasteride's lists ejaculation disorders. [65], [66] We found no controlled study of genital sensation on TRT.

Does hCG help libido or semen volume on TRT?

No trial has tested it. hCG is used with TRT mainly to protect sperm production. [6] Public threads describe both better libido and semen volume after adding it and worse orgasm or mood (see what people report). The hCG guide and the hCG, gonadorelin and enclomiphene comparison cover what it is known to do.

Does SHBG or free testosterone matter?

Sometimes. SHBG is the blood protein that carries testosterone; when it is high, less testosterone is free to act. The European Male Ageing Study followed men for about 4 years, and obesity often lowered their total testosterone. Men whose total testosterone fell while free testosterone stayed normal did not develop new sexual symptoms; only men whose total and free testosterone both fell did. [82] The Society for Endocrinology and the BSSM use calculated free testosterone alongside total testosterone for this reason. [15], [13]

Will morning erections come back?

Often, if testosterone was low. A review of trials found that in men starting below 12 nmol/L, testosterone moderately improved the number of night-time erections, sexual thoughts and motivation, and the Testosterone Trials found night-time erections improved. [9], [29] When morning erections disappear on stable treatment, the same checks as for low libido apply.

Do supplements for libido or erections work on TRT?

None has been tested in men on TRT for this purpose. FDA warns that products sold for sexual enhancement are likely to be contaminated with dangerous hidden ingredients. [70] Doserly's supplement guides, such as tongkat ali and zinc, review each one's own evidence.

What do men on TRT report about sex drive and erections?

Sex drive is one of the most discussed topics in public TRT forums. The threads below are recent public Reddit discussions, read with their replies; they show what people experience, not how often it happens.

What does a good response look like?

Usually a rise in desire within weeks. A man in his 50s who started after very low testosterone readings went from little interest in sex to wanting it daily, alongside better sleep and energy. [83] Another reported much stronger desire only at nine to ten months, after splitting his weekly dose into two injections and several other changes. [84]

Why do some men feel a surge that fades?

It is one of the most common stories. A man in his 30s had strong libido and erections soon after starting weekly injections. Both faded after about two months, and lowering the dose and splitting it did not bring them back. [85] Another felt markedly better for three months on a low weekly dose before libido and morning erections disappeared. A month of cabergoline for raised prolactin changed nothing, and at six months his prolactin was low but his libido still absent. [86], [87] A man switching from pellets to injections had strong erections for five to six weeks, then lost most morning erections, with a trough testosterone of 1,658 ng/dL and a hematocrit of 54.2% at nine weeks. [88] One poster tracked four better days around weeks six to seven, then weeks of flat desire. A higher dose first felt worse, then brought somewhat better erections but not desire by week 15. [89], [90]

What about men whose libido never came back?

These threads are long and frustrating. One man reported three years without libido, morning erections or reliable erections through injections, gel, tadalafil and an aromatase inhibitor. [91] Another described complete loss of desire and severe ED on 100 mg a week, unchanged by DHEA, pregnenolone and kisspeptin. [92] A third, with total testosterone between 1,299 and 1,533 ng/dL, still had low libido after a year; his ferritin was 14 and several other changes clouded the picture. [93] Replies to a man four months in, with a trough level of 600 ng/dL and no libido, pointed to his weight and possible sleep apnea. [94] One poster described years of very low libido across many dose and estradiol changes, during which high testosterone and hCG preceded breast tissue growth that needed surgery. [95]

Do dose, schedule or estradiol changes help?

Changes cut both ways, and most threads changed several things at once. Lowering enanthate from 110 to 90 mg a week improved one man's sleep but lowered his energy and libido without fixing erections. [96] After a prescriber cut a weekly dose because of high free testosterone and a hematocrit of 0.52 L/L, another man reported lower libido, weaker erections and less sensation over four weeks. [97] Going up did not always help either: raising a stable gel dose raised desire at first, then spontaneous erections faded. [98] Switching to every-other-day injections at the same weekly dose raised one man's measured testosterone from 15.5 to 39.8 nmol/L while his libido fell. [99]

Aromatase inhibitor stories are mostly negative or short-lived. One man lowered his dose and started an aromatase inhibitor at the same time and lost libido and morning erections, so the cause could not be separated. [100] Another had one good night after a small anastrozole dose, without a lasting change. [101] Others said an aromatase inhibitor made them feel very unwell or markedly worse. [84], [102]

What do people report about hCG?

Mixed results. One man said changing from larger hCG doses every three days to small daily doses brought stronger libido and orgasms and ended the mood swings. [103] Another felt renewed desire and sensation, and more semen, within days of adding hCG to injections that had stopped working for him. [104] A long-term user found libido and erections improved on hCG but orgasm intensity and semen volume fell. [105] A man on hCG alone had an early boost, then worse erections and less response to ED tablets. [106] No trial has tested any of this.

What do people say about tadalafil and sildenafil on TRT?

That they fix erections, not desire. A man seven weeks into TRT found ED tablets helped erections during use but did nothing for desire or spontaneous erections. [107] Another had little change in erections after three months of testosterone, while daily tadalafil made them reliably stronger; the problem returned when he stopped it. [108] After four years on TRT, one man found a lower tadalafil dose than prescribed clearly helped in the first days. [109] Daily tadalafil made erections so reliable for one poster that he could no longer use them as a signal that something else was changing. [110] Another could not tolerate it, with headache and congestion even at a very low dose. [111]

What about orgasm, sensation and semen volume?

A man in his 50s reported a strong early libido boost that eased, with erections still strong but less sensation and a longer time to climax. [112] After a vasectomy, one man found six months of TRT eased aching testicles but did not restore orgasm pleasure. [113] Another enjoyed stronger morning erections but was disappointed by small semen volume, which he thought may have been modest before treatment too. [114] A man in his 40s found ejaculation became harder after starting, while ED and low desire persisted. [115]

What else turned out to matter?

Many threads end with a cause outside testosterone:

• Finasteride. One man's erections weakened each time he used it, oral or topical. [116]
• Other medicines. An antidepressant and a viral illness in one thread, and bupropion started at the same time as TRT in another. [117], [118]
• Several changes at once. An infection, weight loss and quitting smoking and cannabis, all together. [119]
• Diet. A weight-loss medicine and a strict calorie deficit. [120]
• Sleep. Chronic poor sleep, with trouble tolerating a CPAP machine. [121]
• Thyroid. A badly out-of-range thyroid test, mentioned only late in a thread about dose changes. [122]

Before starting, men with ED asked whether TRT would help; replies described both better and worse erections. [123] A man in his 30s with a testosterone of 330 ng/dL, whose tadalafil was not working, said in a follow-up that he wanted children soon, which changes the choice of treatment. [124]

When desire outruns a partner's

Several threads come from men, and one from a partner, describing a gap in desire after TRT started. A man in his 40s found his libido much higher after two weeks and asked others how often they had sex. [125] A woman described her partner's new drive disrupting her sleep and family life. [126] A man in his 50s with a history of obsessive thoughts found restored libido came with distressing relationship worries. [127] Replies mostly recommended talking openly and, where needed, counseling.

How can you judge a libido story?

Ask: Was testosterone low before treatment, on repeat morning tests? What was the level on treatment, and when in the injection cycle was it drawn? What else changed at the same time: dose, schedule, an aromatase inhibitor, hCG, weight, sleep, alcohol, other medicines, a relationship? Were depression, prolactin and thyroid checked? How long was the wait before judging? And what did the next few months show?

These selected discussions show what people experience and the questions research has not answered. They are not a survey of all men on TRT, a success rate or a substitute for the trials above.

What should you track?

Guidelines review symptoms at each follow-up, for example at 3 months, 6 months and then yearly in the CUA schedule, and judge the sexual response within 3 to 12 months. Use this summary to prepare questions for your prescriber; it is not a personal testing plan. [12], [7], [6], [13], [14]

[12], [7], [16], [11], [17], [65], [34]

The AUA does not recommend formal questionnaires to select or monitor patients; a simple, consistent record of how things are going, noted at the same points, gives your prescriber a clearer picture. [6] The TRT blood work guide covers when to draw each test.

Common questions about TRT and sexual health

Will TRT fix erectile dysfunction?

Sometimes partly, if testosterone is genuinely low. On average TRT raises the erection score by about 2 points, more when testosterone started below 8 nmol/L, and the EAU recommends it first for mild ED in men with low testosterone. For more severe ED, guidelines add or prefer an ED tablet. Men with normal testosterone get no erection benefit. [4], [8], [14], [9] See the research.

How quickly does TRT improve sex drive?

Usually within weeks. A review of time courses found sexual interest began to change at about 3 weeks and leveled off by 6 weeks. The ICSM says 2 to 3 weeks and the Society for Endocrinology 3 to 6 weeks. Erections can take 6 to 12 months, and guidelines judge the overall response at 3 to 12 months. [48], [11], [15] See how long it takes.

Can I take Cialis or Viagra with TRT?

Yes, ED tablets are commonly prescribed alongside testosterone, and several guidelines suggest the combination for men with low testosterone and ED. Trials disagree on whether testosterone adds much once the tablet dose is right. Never take them with nitrate medicines. [10], [13], [78], [63] See combining treatments.

Is the sexual benefit from TRT just a placebo effect?

No. The largest trials compared testosterone with a placebo gel, and desire and activity improved more on testosterone. Placebo effects are real, though: in one ejaculation trial, scores rose almost as much on placebo. A 2014 review also found that, after adjusting for possible publication bias, the benefit held up only in trials partly or fully funded by drug companies, though its authors thought trial design might explain this. [2], [3], [33], [80] See the research.

Will TRT help if my testosterone is borderline?

Probably not for sex. Trials in men with normal or low-normal testosterone found no sexual benefit. The Society for Endocrinology found little evidence of benefit above 12 nmol/L, and the Cochrane review in men without diagnosed low testosterone found "little to no effect" on erections. The Testosterone Trials' finding that no testosterone threshold predicted response applied only to men already below 275 ng/dL. [44], [15], [41], [29] See the key numbers.

Can TRT make sex drive or erections worse?

It can happen. Labels list decreased as well as increased libido, and public threads describe desire fading after an early surge. In one diabetes trial the short erection score favored placebo. Changes in dose, an added aromatase inhibitor or a new medicine are common in these stories, so each needs checking. [53], [45], [11] See why libido can stay low.

Does TRT cause infertility?

It can. Testosterone therapy lowers sperm production, sometimes to zero, and labels warn that reduced fertility can be irreversible. Guidelines advise against it for men trying to conceive. [60], [57], [6] See the TRT and fertility guide.

Glossary

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

5-alpha reductase inhibitor

A medicine, such as finasteride (Propecia) or dutasteride (Avodart), that blocks the conversion of testosterone to DHT. They are used for hair loss and an enlarged prostate, and their labels list sexual side effects.

Aromatase inhibitor

A medicine, such as anastrozole, that blocks the enzyme that turns testosterone into estradiol. The VA does not recommend them for men on testosterone, and the ICSM advises against using them for low desire.

Controlled trial

A study that compares people who receive a treatment with a similar group who do not, often receiving a placebo instead. Randomly assigning people to each group makes the comparison fairer.

DHT (dihydrotestosterone)

A stronger hormone made from testosterone in tissues such as the skin and prostate. Finasteride and dutasteride block its production.

Erectile dysfunction (ED)

Trouble getting or keeping an erection firm enough for sex. It has many causes, including blood-vessel disease, diabetes, medicines, stress and low testosterone.

Estradiol

The main form of estrogen. In men it is made mostly from testosterone, so it rises when testosterone rises.

Free testosterone

The small share of testosterone in the blood that is not bound to proteins and can act on tissues directly. It is usually calculated from total testosterone, SHBG and albumin.

Clinical guideline

Recommendations written by a medical society or health system, based on its review of the evidence and expert judgment. Different guidelines can reach different conclusions.

Hazard ratio

A measure comparing how often an event happens over time in two groups. A hazard ratio of 1 means no difference; 0.96 means about 4% lower in the first group.

hCG (human chorionic gonadotropin)

A hormone that acts like LH and tells the testicles to make testosterone and sperm. It is sometimes used alongside TRT to protect sperm production.

Hypogonadism

Low testosterone caused by a problem in the testicles or in the brain and pituitary signals that control them, confirmed with symptoms and repeated morning blood tests.

IIEF (International Index of Erectile Function)

A standard questionnaire about sexual function. Its erectile function part scores up to 30 points, higher is better, and trials report the change in this score.

Intramuscular (IM)

Injected into a muscle. Most testosterone cypionate and enanthate is given this way.

Product label (prescribing information)

The official document approved by a medicines regulator for a product, describing its approved uses, doses, warnings and monitoring. In the UK it is called the summary of product characteristics.

Late-onset hypogonadism

Low testosterone with symptoms that appears in middle or older age, often alongside weight gain or other illnesses. Research definitions require sexual symptoms as well as low blood levels.

LH (luteinizing hormone)

A pituitary hormone that tells the testicles to make testosterone. Testosterone therapy switches it off.

Libido

Sex drive: interest in and desire for sex. It is separate from erectile function, the physical ability to get an erection.

Minimal clinically important difference

The smallest change in a score that people notice as meaningful. The Cochrane review of testosterone used 4 points on the erection score.

Meta-analysis and systematic review

A systematic review gathers all studies on a question in a planned way. A meta-analysis combines their results statistically.

Morning (nocturnal) erections

Erections that happen during sleep and are often noticed on waking. Having fewer of them is one of the symptoms most closely tied to low testosterone.

Nitrates

Medicines such as nitroglycerin, taken for chest pain (angina). Taking them with sildenafil, tadalafil or another PDE5 inhibitor is contraindicated because blood pressure can drop dangerously.

PDE5 inhibitor

The main group of ED tablets, including sildenafil (Viagra) and tadalafil (Cialis). They help the penis fill with blood during sexual arousal; they do not raise desire.

Placebo

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

Priapism

An erection that lasts for hours without sexual stimulation. Testosterone labels list it as a possible side effect and tell men to report erections that are too frequent or persistent.

Prolactin

A hormone from the pituitary gland. Very high levels lower sex drive and testosterone; some medicines and pituitary tumors can raise it.

PSA (prostate-specific antigen)

A protein made by the prostate and measured in a blood test. It is checked before and during testosterone therapy.

Secondary hypogonadism

Low testosterone because the pituitary gland or brain does not send enough signal (LH) to the testicles, rather than because the testicles themselves fail.

SHBG (sex hormone-binding globulin)

A blood protein that carries testosterone. Testosterone bound to it is not immediately available to tissues, so SHBG affects how much free testosterone there is.

Transdermal

Absorbed through the skin, as with testosterone gels and patches.

TRT (testosterone replacement therapy)

Prescribed testosterone, by injection, gel or other forms, for men with low testosterone.

WADA

The World Anti-Doping Agency, which publishes the list of substances banned in sport. Testosterone is prohibited at all times.

How this guide was researched

This guide is built from a thorough review of the sources cited throughout it: clinical guidelines from medical bodies in the US, Europe, the UK, Canada and internationally, product labels, published clinical trials and reviews, trial registries and regulatory documents. We also reviewed public online forums where men on TRT describe changes in their sex drive and erections.

The guide cites 127 sources, including 30 original studies in people, 12 clinical guidelines and statements, and 45 public community discussions. Each type of source answers a different question. Guidelines and labels show what clinicians are told to do. Trials and reviews show what was measured. Personal accounts show what individual people experienced. Every numbered citation links to its entry below, labeled by source type.

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