PT-141

bremelanotide, Vyleesi (brand name of the approved medicine), PT-141, Rekynda (development name)

Longevity & cellular

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Note on this profile. Bremelanotide is an approved prescription medicine in the United States (Vyleesi) for one specific indication in premenopausal women. This page explains the published science. Use outside a prescription — including in men, where it is not approved anywhere, and including grey-market lyophilised versions — is off-label or unapproved and carries the risks discussed below.

Summary

Class: Synthetic cyclic heptapeptide (7 amino acids); melanocortin receptor agonist, derived from Melanotan II
Mechanism: Activates melanocortin receptors (mainly MC4R) in brain regions involved in sexual arousal; it is not a blood-vessel drug like sildenafil
Routes studied: Subcutaneous autoinjector (approved); intranasal (earlier trials, abandoned); subcutaneous in men (Phase 1–2); community subcutaneous
Dose range reported: Approved: 1.75 mg subcutaneous as needed, at least 45 minutes before anticipated sexual activity, no more than one dose in 24 hours and no more than eight doses per month. Men's trials (intranasal/subcutaneous): roughly 4–20 mg intranasal, 0.3–10 mg subcutaneous. Community (men and women, unapproved): 0.5–2 mg subcutaneous as needed
Half-life: ~2.7 hours (subcutaneous); peak blood level around 1 hour
Storage: Approved autoinjector: room temperature below 25 °C, protect from light. Lyophilised vials: refrigerate; reconstituted: refrigerate, community practice is use within ~4 weeks
Regulatory status: Approved in the US (2019) for HSDD in premenopausal women; not approved for men anywhere; not authorised in the EU or UK †

Doses are as reported in studies or by the community — never recommendations.

1What it is

Bremelanotide is a small ring-shaped peptide of seven amino acids. It was discovered in the 1990s at the University of Arizona as a breakdown product of Melanotan II, after men in tanning studies reported unexpected erections. Palatin Technologies developed it first as a nasal spray for erectile dysfunction in men. That programme stopped in 2007–2008 because of blood-pressure rises, and development switched to a injection for low sexual desire in women.

The FDA approved it in June 2019 as Vyleesi for acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women — persistent low desire that causes distress and is not explained by a medical condition, a relationship problem or another drug. It is the only melanocortin approved for a sexual indication. Unlike PDE5 inhibitors (sildenafil, tadalafil), it acts in the brain rather than on penile or clitoral blood flow, and it does not change hormone levels.

2How it's thought to work

The melanocortin system is a family of five receptors (MC1R–MC5R) normally activated by the hormone α-MSH. Bremelanotide activates several of them, with the highest affinity for MC4R and MC3R and some activity at MC1R (the receptor on pigment cells, which explains the skin-darkening side effect).

MC4R in the hypothalamus. activation in the medial preoptic area increases dopamine release, a pathway tied to sexual motivation. In female rats it increases solicitation behaviour (Pfaus 2004); in male rats it produces erections.

Not hormonal. it does not raise testosterone or oestrogen, and its effect does not depend on them.

Not vascular. erections in men appear to be centrally triggered rather than caused by direct vasodilation.

Acts on melanocortin receptors (mainly MC4R) in brain areas involved in arousal; the signal travels down the spinal cord. It is not a blood-vessel drug.Schematic — not to scale

The precise human brain mechanism has not been mapped.

3What the research shows

Low sexual desire (HSDD) in premenopausal women

RECONNECT consisted of two identical 24-week Phase 3 (1,267 women in total) of 1.75 mg as needed vs placebo. Both met their co-primary endpoints: the desire score of the Female Sexual Function Index improved by about 0.3–0.4 points more than placebo (on a scale running 1.2–6), and distress scores fell modestly more than placebo. The number of "satisfying sexual events" — a secondary endpoint — did not differ significantly from placebo. About 18% of women on the drug stopped because of side effects, almost all nausea, vs 2% on placebo (Kingsberg 2019; Simon 2019, Obstet Gynecol). A 52-week open-label extension showed the effect held, and pigmentation changes continued to accrue (Simon 2019). [1][2]

Dose-finding in women

A Phase 2b trial compared 0.75, 1.25 and 1.75 mg; the top dose was selected for Phase 3 (Clayton 2016, Womens Health). [3]

Graded A/B (development abandoned)

Erectile dysfunction in men

Early controlled studies showed erections measured by RigiScan after intranasal doses in men with mild-to-moderate ED (Diamond 2004, Int J Impot Res) and after doses in men who had not responded to sildenafil (Rosen 2004, Int J Impot Res). A larger randomised trial in sildenafil non-responders also reported benefit (Safarinejad & Hosseini 2008, J Urol). Blood-pressure increases ended the programme; bremelanotide is not approved for men anywhere. [4][5][6]

Female sexual arousal disorder (intranasal)

Small early crossover studies of intranasal dosing in women reported increased arousal and desire (Diamond 2006, J Sex Med); superseded by the subcutaneous programme.

Libido, "sexual enhancement" in healthy people

Community use in men and in people without a diagnosis rests on the trial findings above and anecdote; no study has looked at healthy volunteers' sexual experience.

4Reported side effects and interactions

Literature-reported

nausea (about 40% vs 1% on placebo; usually with the first doses and often improving), flushing (~20%), injection-site reactions (~13%), headache (~11%), vomiting (~5%), cough, fatigue, hot flush, tingling, dizziness, nasal congestion. A transient rise in blood pressure (mean about +6 mmHg systolic, +3 mmHg diastolic) with a small fall in heart rate, peaking within 4 hours and resolving within 12; because of this it is contraindicated in uncontrolled hypertension or known cardiovascular disease. Focal hyperpigmentation of the face, gums or breasts occurred in 1% of trial participants, but in 38% of volunteers given eight doses on consecutive days; it may not fully resolve and is more likely in darker skin.

Community-reported

nausea (some people pre-dose with an antiemetic; 13% did so in trials), flushing, loss of appetite, spontaneous erections in men, darkening of moles and freckles, yawning and stretching, slow onset (hours) and effects spilling into the next day, headache.

Theoretical. MC1R stimulation and pigmentation changes raise the same mole-surveillance question as the melanotans; trials showed no melanoma signal but were short. Not studied in pregnancy; the label advises against use and recommends contraception.

Interactions. bremelanotide slows gastric emptying, which can delay or reduce absorption of oral medicines; the label specifically advises against co-use with oral naltrexone (used for alcohol or opioid dependence) because naltrexone exposure fell markedly. Additive blood-pressure effects with other pressor substances are a theoretical concern.

Markers researchers commonly monitor

Marker	Why it's watched
Blood pressure and heart rate before and in the hours after a dose	the transient rise is the main safety finding and the basis of the cardiovascular contraindication.
Skin and mucosal pigmentation, including a baseline record of moles	hyperpigmentation accumulates with frequent dosing.
Nausea and vomiting frequency	the main reason people stop.
Hormones (testosterone, oestradiol) are not expected to change; measuring them checks that assumption rather than tracking an effect
No compound-specific blood markers are established; general baselines (CBC, CMP) only

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

The Vyleesi autoinjector needs no preparation. vials (commonly 10 mg) are with ; because the per-dose amount is in the 0.5–2 mg range, the concentration chosen determines whether the injected volume is practical. Swirl, do not shake; protect from light.

Open in calculator, pre-loaded →

6Commonly studied alongside

Sildenafil (one small study of low-dose intranasal bremelanotide plus sildenafil in men); Melanotan II (the parent compound); oxytocin and kisspeptin (separate research lines on sexual brain processing, not combined with bremelanotide in trials).

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved June 2019 (Vyleesi) for acquired, generalised HSDD in premenopausal women; prescription-only. Not approved for men
European Union	Not authorised †
United Kingdom	Not licensed †
Australia	Not approved; would be prescription-only (Schedule 4) by class †
South Africa	Not registered with SAHPRA †
Sport (WADA)	Not on the Prohibited List as of review date †

8Open questions

Would bremelanotide work for men at tolerable blood pressure? Development stopped before this was settled.
Long-term pigmentation and mole safety with years of intermittent use.
Whether the modest average FSFI change translates into a meaningful difference for most individual users.
Postmenopausal women and women on hormone therapy were excluded from the approval trials.

9References

1Kingsberg SA et al. (2019). Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. PubMed · DOI
2Simon JA et al. (2019). Long-term safety and efficacy of bremelanotide for hypoactive sexual desire disorder. Obstet Gynecol. PubMed · DOI
3Clayton AH et al. (2016). Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial. Womens Health (Lond). PubMed · DOI
4Diamond LE et al. (2004). Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. Int J Impot Res. PubMed · DOI
5Rosen RC et al. (2004). Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra. Int J Impot Res. PubMed · DOI
6Safarinejad MR, Hosseini SY (2008). Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study. J Urol. PubMed · DOI
7Pfaus JG et al. (2004). Selective facilitation of sexual solicitation in the female rat by a melanocortin receptor agonist. Proc Natl Acad Sci USA. PubMed · DOI
8Vyleesi (bremelanotide injection) US prescribing information (current label). PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

25 Oct 2026Profile published — awaiting medical review

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