PT-141
| Category | Other Peptides |
| Goals | Sexual Health |
| Evidence level | Approved (FDA-approved drug for one specific indication) |
| Legal status | Prescription drug (Vyleesi); research-chemical versions are unapproved |
| FDA status | Approved 2019 as Vyleesi for HSDD in premenopausal women |
| Half-life | ~2.7 h (range 1.9–4.0 h) after subcutaneous dosing |
| Routes | Subcutaneous (approved) · Intranasal (off-label/research) |
| CAS / MW / Sequence | 189691-06-3 · 1025.2 g/mol · Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (cyclic heptapeptide) |
| Last reviewed | 2026-06-05 |
In one line
A melanocortin receptor agonist that acts on the brain rather than the vasculature to influence sexual desire — and the only peptide here that is an FDA-approved drug, marketed as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.
Evidence at a glance
PT-141 (bremelanotide) is FDA-approved, but only for one narrow indication: generalized, acquired HSDD in premenopausal women. Approval does not extend to men, postmenopausal women, or erectile dysfunction. “On-demand” use for libido/erections in those groups is off-label or research-only, and most peptide-market PT-141 is unapproved research chemical. See Evidence Grading Explained and the Disclaimer.
Key Takeaways
- A cyclic heptapeptide and analogue of α-MSH that activates melanocortin receptors (mainly MC3/MC4) in the central nervous system.
- Works centrally on desire/arousal pathways, not by increasing blood flow like PDE5 inhibitors (Viagra/Cialis) — a different mechanism.
- FDA-approved as Vyleesi (2019) for premenopausal HSDD; this is the strongest evidence among the peptides on this wiki.
- Use in men or for erectile function is off-label/anecdotal; the popular “on-demand libido shot” is not the approved use.
- Common, well-documented side effect: nausea; also transient blood-pressure increase and, with melanocortin agonism, possible skin/mole darkening.
What Is It
PT-141, generically bremelanotide, is a synthetic cyclic heptapeptide lactam derived from α-melanocyte-stimulating hormone (α-MSH). It is the active metabolite of an earlier compound, Melanotan II, that was repurposed away from tanning toward sexual function. It is marketed as Vyleesi (an autoinjector) for the treatment of hypoactive sexual desire disorder (HSDD) — persistently low sexual desire causing distress — in premenopausal women.
Mechanism of Action
- Melanocortin receptor agonism (established) — non-selective agonist across MC1–MC5, acting primarily at MC3 and MC4 receptors in the central nervous system.
- Central action on desire/arousal (established for the approved indication) — influences hypothalamic pathways involved in sexual motivation, rather than acting peripherally on genital blood flow.
- Distinct from PDE5 inhibitors (established) — unlike sildenafil/tadalafil, it does not work via the nitric-oxide/cGMP vasodilation pathway, so its effect is on desire more than mechanical erection.
Limitations
The mechanism is best characterized for the approved female-HSDD use. The precise downstream circuitry that produces a behavioral effect is only partly understood, and male/erectile applications rest on smaller or older trials and anecdote.
Evidence by Outcome
| Outcome | Evidence | Notes |
|---|---|---|
| HSDD in premenopausal women | Approved | Basis for FDA approval (RECONNECT phase 3 trials); modest but statistically significant effect |
| Female sexual arousal/desire (general) | Clinical | Supported by trials, but approval is narrow to premenopausal HSDD |
| Erectile dysfunction (men) | Clinical / Anecdotal | Early SC and intranasal trials; intranasal program discontinued over blood-pressure concerns; not approved |
| ”On-demand” libido boost (either sex) | Anecdotal | Widely reported in peptide community; off-label or research-only |
| Postmenopausal women | Anecdotal | Not an approved population; little controlled data |
Reported Dosing
Not medical advice
The approved product has a defined label dose; figures below also include community-reported off-label use, which is not a clinical recommendation. See Reconstitution & Dosing Math and Injection Technique.
| Route | Dose | Frequency | Notes |
|---|---|---|---|
| Subcutaneous (Vyleesi, approved) | 1.75 mg | As needed, ≥45 min before sexual activity | Max 1 dose/24 h; no more than 8 doses/month per label |
| Subcutaneous (research/off-label) | ~0.5–2 mg | On demand | Lower doses sometimes used to limit nausea |
| Intranasal (research) | Varied | On demand | Discontinued in formal development; quality/dosing unreliable |
Pharmacokinetics
Mean terminal half-life ~2.7 hours (range ~1.9–4.0 h); peak plasma levels ~1 hour after subcutaneous injection. It is cleared largely by hydrolysis of the peptide with renal and fecal elimination of metabolites. The relatively short half-life fits its on-demand dosing pattern. See Half-Life & Pharmacokinetics.
Side Effects & Risks
- Nausea is the most common adverse effect (frequent in trials; sometimes requiring an antiemetic or dose reduction).
- Transient increase in blood pressure and decrease in heart rate after dosing — contraindicated in uncontrolled hypertension or known cardiovascular disease per label.
- Skin/gum hyperpigmentation and darkening of moles/freckles can occur with melanocortin agonism, more so with repeated use.
- Flushing, headache, injection-site reactions, vomiting.
- Sourcing risk: non-Vyleesi PT-141 is sold as a research chemical with variable identity/purity — see Sourcing and Red Flags & Scams.
- See Side Effects & Risk Management and consider Bloodwork & Monitoring if used chronically.
Cycling
As an on-demand drug, PT-141 is not “cycled” in the bodybuilding sense; the label caps frequency (no more than one dose/24 h, ≤8/month). Community off-label use is typically occasional rather than continuous. See Cycling.
Stacks It Appears In
- Sometimes discussed alongside PDE5 inhibitors for combined desire + erectile effect (off-label; additive blood-pressure effects are a concern).
- Compared and contrasted with Melanotan II, its structural relative.
Comparisons
- Melanotan II — the parent compound; MT-II is a non-selective melanocortin agonist used (research-only) for tanning and libido, whereas PT-141 is the refined, approved libido agent.
- Versus PDE5 inhibitors: PT-141 targets desire centrally; PDE5 inhibitors target erection peripherally.
Sourcing & Quality
The only approved form is Vyleesi by prescription. Anything sold as “PT-141” research peptide is unapproved, with identity/purity not guaranteed: How to Read a CoA, Red Flags & Scams, Sourcing. Reconstitution and storage: Reconstitution & Dosing Math, Storage & Handling. No vendors are endorsed here.
Legal & Regulatory Status
(As of 2026-06-05.) Bremelanotide is an FDA-approved prescription drug (Vyleesi, NDA 210557, approved June 2019) for HSDD in premenopausal women. Use outside that indication is off-label. PT-141 sold as a “research chemical” is not approved for human use and is unlawful to market for human consumption. It may also be prohibited in tested sport. See Regulatory & Legal Status.
FAQ
Is PT-141 FDA-approved? Yes — as Vyleesi, but only for hypoactive sexual desire disorder in premenopausal women. Other uses are off-label or research-only.
Does it work for men / erectile dysfunction? Early trials explored ED, but it is not approved for men; an intranasal ED program was discontinued partly over blood-pressure effects. Male use is off-label/anecdotal.
How is it different from Viagra? PT-141 acts centrally on desire via melanocortin receptors; PDE5 inhibitors act peripherally on blood flow. Different mechanisms, different targets.
Why does it cause nausea? Nausea is a known melanocortin-agonist effect and is the most common adverse event; lower doses and timing may help.
References
- U.S. FDA (2019). VYLEESI (bremelanotide injection) Prescribing Information — NDA 210557.
- Kingsberg S.A. et al. (2019). “Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials (RECONNECT).” Obstetrics & Gynecology.
- Clayton A.H. et al. (2016). “Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial.” Women’s Health.
- Bremelanotide — LiverTox, NCBI Bookshelf, NIH (overview and pharmacology).
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