PT-141: uses, evidence and status | Inside Your Peptides

compound file

The answer, first. A cyclic melanocortin agonist derived from melanotan II, developed by Palatin Technologies and marketed since 2019 as the bremelanotide autoinjector VYLEESI. The strongest evidence is for low desire in premenopausal women, graded A — approval or replicated trials.

Two identical randomised trials enrolled 1,267 women. Desire scores rose 0.35 over placebo and distress fell 0.33, both P<.001 ¹.

Effect sizes are small and the scales carry contested validity ³. The rest of what it is sold for — desire in men, desire after menopause — grade D or E: animal or mechanism data with no controlled human outcome.

What it is used for

Every use graded on its own evidence, not the compound as a whole. 4 outcomes, ranked by what the human record supports.

#outcome · human · animal · gradewhat the best evidence actually shows

01Low desire in premenopausal women2 phase 3 trials, n=1,267 · supportinggrade ATwo identical randomised trials enrolled 1,267 women. Desire scores rose 0.35 over placebo and distress fell 0.33, both P<.001 ¹. Effect sizes are small and the scales carry contested validity ³.

02Erections in men1 crossover, n=19 · supportinggrade CIntranasal PT-141 plus 25 mg sildenafil beat sildenafil alone on RigiScan in 19 men ⁴. The one larger male trial, 342 men, carries a 2023 expression of concern ⁵.

03Desire in menno trial · melanocortin-4 arousal modelsgrade DThe male studies measured erections, not desire, and used an intranasal formulation rather than the approved autoinjector ⁴⁵. The label states it is not indicated for men ⁶.

04Desire after menopauseno trial · supportinggrade DThe phase 3 programme enrolled premenopausal women only, mean age 39 ¹. Prespecified subgroup analyses cover age and severity inside that population, not beyond it ². The label excludes it ⁶.

gradewhat it means

ARegulatory approval, or multiple adequately-powered trials agreeing with each other

BAt least one well-powered human randomised trial, with the direction replicated

CSmall or open-label human trials only

DAnimal or mechanism data only, with no controlled human outcome

EA claim the human trials have already killed

How it works

The proposed mechanism, in three steps. A mechanism is a reason to run a trial, never a substitute for one.

1targetAgonises melanocortin receptors, MC4 in the hypothalamus most relevantly, alongside MC1 on melanocytes ⁷.

2signalCentral MC4 activation acts on the pathways that generate desire and arousal. It does not act on genital blood flow ⁴.

3effectDesire scores move modestly ¹. MC1 crossover produces the flushing, nausea and focal hyperpigmentation the label records ⁶.

What it does not do

Claims the current record does not support. Worth knowing before you set expectations.

not supported by the evidence

It improves arousal and orgasm. Eight of eleven prespecified efficacy outcomes went unpublished until reanalysis. Effect sizes on them ran from nil to small ³.
A research vial is VYLEESI. The approval covers a 1.75 mg autoinjector with a fixed dose and an eight-dose monthly ceiling ⁶. Not reconstituted powder.
It has no blood pressure effect. The label records maximal rises of 6 mmHg systolic and 3 mmHg diastolic, peaking two to four hours after a dose ⁶.
It works like Viagra. It acts centrally on desire, not on genital blood flow, and the male data comes from a co-administration study with sildenafil ⁴.

How it is used

What published protocols administered, and what the community reports doing. Descriptive on both counts, and never a recommendation.

routeSubcutaneous. The approved autoinjector goes into the abdomen or thigh at least 45 minutes before anticipated sexual activity ⁶.

formatSingle-use 1.75 mg autoinjector. Research-market PT-141 is lyophilised powder for reconstitution.

published dosesThe label schedules 1.75 mg subcutaneously as needed, one dose in 24 hours, no more than eight a month ⁶. The phase 3 trials dosed that way for 24 weeks ¹. The male studies used 7.5 mg intranasally with sildenafil ⁴ and 10 mg intranasally alone ⁵.

human pharmacokineticsTmax about 1.0 hour, terminal half-life about 2.7 hours, subcutaneous bioavailability near 100% ⁶.

reported conventionsAs reported on men's health and peptide forums, 2015-2026: a single dose taken some hours ahead rather than 45 minutes. Often a fraction of the label amount, to blunt nausea. Rarely more than once or twice a week. Convention, not guidance.

commonly paired withKisspeptin-10 Oxytocin

This site does not publish protocols to follow. The doses above are what studies administered or what users report, stated as facts about the literature and the market. How protocols are structured, mixing and storage and the reconstitution calculator cover the arithmetic.

What to expect

Where a trial measured it, the trial. Where only the community reports it, that is said out loud.

onsetThe label sets dosing at least 45 minutes before activity, and plasma peaks around one hour ⁶. In the phase 3 trials the endpoint was change across 24 weeks, not per-dose response ¹. The label directs review after eight weeks without improvement ⁶.

most common reportNausea. It affected 40.0% of women in the phase 3 trials against 1.3% on placebo, and it drove 8% to stop ⁶.

adverse effectsTrial rates, bremelanotide versus placebo: nausea 40.0% versus 1.3%, flushing 20.3% versus 0.3%, headache 11.3% versus 1.9% ⁶. Injection site reactions ran 13.2% versus 8.4%, and vomiting 4.8% versus 0.2% ⁶. Focal hyperpigmentation 1%, rising to 38% with eight consecutive daily doses ⁶.

the stop signalThe label directs discontinuation after eight weeks without improvement, and contraindicates use in uncontrolled hypertension or known cardiovascular disease ⁶. Nausea stopped 8% of trial participants ⁶.

Approval and status

What regulators and sport bodies have actually said, separately from what the evidence shows.

approvalFDA approved 21 June 2019 for acquired, generalised HSDD in premenopausal women.

FDAApproved as VYLEESI, a 1.75 mg autoinjector. The label states it is not indicated for men, for postmenopausal women, or to enhance sexual performance.

sport [WADA]Not named on the Prohibited List. It is an approved medicine.

sold asapproved medicine

Check the vial

The grade above describes a molecule studied under controlled conditions. It says nothing about the powder in a particular vial.

That gap is the one part of this market a reader can actually close. How to read a certificate of analysis covers the five measures in five minutes, and the 2026 audit grades vendors on the documents they publish against a rubric printed in full.

Questions we get

What is PT-141 used for?

One approved thing and several unapproved ones. Bremelanotide is approved for acquired, generalised hypoactive sexual desire disorder in premenopausal women, on the strength of two identical phase 3 trials in 1,267 people.

Off label it is bought by men for libido and erections, and by postmenopausal women for desire. The label states explicitly that it is not indicated for men, not indicated after menopause, and not indicated to enhance sexual performance.

How is PT-141 used?

Described rather than advised. The approved product is a single-use 1.75 mg autoinjector, into the abdomen or thigh, at least 45 minutes before anticipated sexual activity. One dose in 24 hours, no more than eight a month.

As reported on forums since 2015, research-market use runs to fractions of that dose, taken further ahead of time, mostly to blunt nausea. Rarely more than twice a week. Convention, not guidance.

How long does PT-141 take to work?

Plasma peaks around an hour after a dose, which is why the label sets a 45-minute lead time. But the trials did not measure per-dose response. They measured change in desire and distress across 24 weeks of as-needed use.

The label directs discontinuation if there is no improvement after eight weeks. That gap between a one-hour peak and an eight-week judgment is the honest answer to the question.

Is PT-141 an approved drug?

Yes, for one indication and one population. FDA approved bremelanotide in June 2019 for acquired, generalised HSDD in premenopausal women. An approval attaches to a named indication, a named dose and a manufactured product.

It does not extend to a research vial, to men, to postmenopausal women, or to a dose worked out on a forum. Our index grades it approved on clinical evidence and high on community adoption, separately and on purpose.

How big is the effect in the trials?

Small, and that matters more here than usual. Desire scores rose 0.35 points over placebo and distress fell 0.33, both statistically significant across 1,267 women. A 2024 reanalysis found eight of eleven prespecified efficacy outcomes were never published.

Effect sizes on those eight ranged from nil to small. The same reanalysis found the desire and distress scales carry weak validity evidence in this population. Approval and clinical benefit are not the same measurement.

References

Kingsberg SA, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol. 2019;134:899-908. PMID 31599840
Simon JA, et al. Prespecified and Integrated Subgroup Analyses from the RECONNECT Phase 3 Studies of Bremelanotide. J Womens Health. 2022;31:391-400. PMID 35230162
Spielmans GI, Ellefson EM. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. J Sex Res. 2024;61:540-561. PMID 36809187
Diamond LE, et al. Co-administration of low doses of intranasal PT-141, a melanocortin receptor agonist, and sildenafil to men with erectile dysfunction results in an enhanced erectile response. Urology. 2005;65:755-9. PMID 15833522
Safarinejad MR, Hosseini SY. Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study. J Urol. 2008;179:1066-71. Expression of concern, J Urol 2023. PMID 18206919
VYLEESI [bremelanotide] injection, for subcutaneous use. US prescribing information, DailyMed. dailymed.nlm.nih.gov
Mayer D, Lynch SE. Bremelanotide: New Drug Approved for Treating Hypoactive Sexual Desire Disorder. Ann Pharmacother. 2020;54:684-690. PMID 31893927
Althof S, et al. Responder Analyses from a Phase 2b Dose-Ranging Study of Bremelanotide. J Sex Med. 2019;16:1226-1235. PMID 31277966
Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol. 1998;160:389-93. PMID 9679884

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