A tier · strong
The only compound here with full (non-accelerated) FDA approval supported by two replicated positive Phase 3 randomized trials, held back from S only by a small effect size and a 40% nausea rate.
pt-141
Bremelanotide is a cyclic heptapeptide melanocortin receptor agonist approved by the FDA in 2019 as Vyleesi for acquired, generalized hypoactive sexual desire disorder in premenopausal women. Two identical Phase 3 randomized trials met their co-primary endpoints, though the absolute effect sizes were small and nausea affected 40% of treated patients.
the explanation
PT-141 is an FDA-approved injectable drug, sold as Vyleesi, for premenopausal women with distressingly low sexual desire. It works through brain pathways rather than blood flow, and while two large trials showed it genuinely beats placebo, the improvement is modest and about 4 in 10 women get nausea.
regulatory status
FDA approved (2019)
PT-141 is FDA-approved as Vyleesi for acquired, generalized hypoactive sexual desire disorder in premenopausal women — a full approval on replicated Phase 3 evidence, in contrast to SS-31/elamipretide which received accelerated approval as Forzinity in September 2025, and to Semax and Selank which sit on Russian national lists with no FDA approval
how it works · proposed mechanism
Bremelanotide acts centrally on melanocortin pathways rather than on peripheral blood flow.
Melanocortin receptor agonist
It is a non-selective agonist at melanocortin receptors, with central MC4R activity considered the most likely driver of its effect on sexual desire. The precise mechanism by which this produces the therapeutic effect is not fully established even in the approved labelling.
Central, not vascular
Unlike PDE5 inhibitors, which act on peripheral vascular smooth muscle to enable erection, bremelanotide works on brain circuitry governing desire. This is why it is indicated for a desire disorder rather than an arousal or performance one.
Transient pressor effect
Blood pressure rises by a maximal 6 mmHg systolic and 3 mmHg diastolic, peaking 2-4 hours after dosing and returning to baseline within 12 hours. This underlies the label contraindication in uncontrolled hypertension or known cardiovascular disease.
Melanocortin pigmentation overlap
Because melanocortin receptors also govern melanogenesis, focal hyperpigmentation occurred in 1% of patients over up to 8 monthly doses. Resolution was not confirmed in all affected patients.
what’s reported
evidence shape
5 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
The statistical wins are real but the clinical magnitude is small: a +0.35 change on the FSFI desire domain and a -0.33 change on a single distress item are modest shifts whose real-world meaningfulness was contested at the time of approval. Against that sits a 40% nausea rate requiring anti-emetics in 13% and causing 8% to discontinue, plus focal hyperpigmentation that did not resolve in every affected patient.
key published findings
- Human RCT: two identical Phase 3 trials (RECONNECT) randomized 1,267 premenopausal women; pooled FSFI-Desire improved +0.35 versus placebo (p<0.001) over 24 weeks (Obstetrics & Gynecology, 2019)
- Human RCT: pooled FSDS-DAO item 13 (distress about low desire) improved -0.33 versus placebo (p<0.001); individually, study 301 -0.37 (p<0.001) and study 302 -0.29 (p=.005)
- Human (label/PK): mean terminal half-life approximately 2.7 hours, range 1.9-4.0 hours (FDA prescribing information, 2019)
- Human safety (label): nausea 40%, flushing 20.3%, injection site reactions 13.2%, headache 11.3%, vomiting 4.8%; nausea required anti-emetic therapy in 13% and led to discontinuation in 8%
- Human safety (label): transient blood pressure increase of maximal 6 mmHg systolic / 3 mmHg diastolic peaking at 2-4 hours; focal hyperpigmentation in 1% over up to 8 monthly doses, not confirmed to resolve in all patients
limitations of the evidence
- Effect sizes are small in absolute terms and the clinical meaningfulness of a 0.35-point FSFI-Desire shift has been debated since approval
- Trials were conducted only in premenopausal women; efficacy and safety in postmenopausal women and in men are not established by the approved evidence base
- Long-term safety beyond the trial duration and beyond 8 monthly doses is not well characterised, particularly for cumulative hyperpigmentation
documented safety signals
- Nausea in 40% of patients, requiring anti-emetic therapy in 13% and causing discontinuation in 8%
- Contraindicated in uncontrolled hypertension or known cardiovascular disease due to transient pressor effect
- Focal hyperpigmentation in 1% of patients, with higher risk in darker skin and resolution not confirmed in all cases
- Flushing (20.3%), headache (11.3%), injection site reactions (13.2%) and vomiting (4.8%)
identity
| full name | Bremelanotide |
| category | Sexual Health |
| modality | peptide |
| formula | C50H68N14O10 |
| molar mass | 1025.2 g/mol |
| cas | 189691-06-3 |
| half-life | ~2.7 hours (range 1.9-4.0 h) |
| sequence | Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH |
laboratory handling
| storage | Approved product is supplied as a prefilled autoinjector stored at controlled room temperature; lyophilised research-grade material is held at -20°C, with reconstituted solution refrigerated at 2-8°C and protected from light. |
| solubility | Soluble in sterile or bacteriostatic water; the approved formulation is an aqueous solution for subcutaneous injection. |
| co-studied with | The FDA label warns that bremelanotide may slow gastric emptying and reduce absorption of orally administered drugs, and it is not recommended with certain oral medications including naltrexone. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
5 citedUS Food and Drug Administration · 2019 · official
US Food and Drug Administration · 2019 · official
ClinicalTrials.gov · 2015 · official
Obstetrics & Gynecology · 2019 · peer-reviewed
Obstetrics & Gynecology · 2019 · peer-reviewed
others in Sexual Health