Desire, reignited from within
Injection, Nasal · Prescription
Educational content. This page describes PT-141 (Bremelanotide) for informational purposes only and is not medical advice, diagnosis, or treatment. Consult a licensed provider before starting, stopping, or modifying any therapy.
Researched and maintained by the PepHookup team. Regulatory status last verified April 12, 2026.
The two pivotal RECONNECT Phase 3 trials in 1,267 premenopausal women with HSDD showed statistically significant gains in sexual desire and reductions in the distress tied to low desire over 24 weeks.[1]
A single 1.75 mg subcutaneous dose is self-administered at least 45 minutes before anticipated activity. Absolute bioavailability is about 100% and there is no daily medication to take.[6]
PT-141 (bremelanotide, marketed as Vyleesi) is a synthetic cyclic 7-amino-acid peptide, a melanocortin receptor agonist modeled on alpha-melanocyte-stimulating hormone (alpha-MSH). In June 2019 the FDA approved it for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, the first and one of the few approved therapies that addresses desire through the central nervous system rather than peripheral blood flow.
Bremelanotide grew out of melanocortin research on melanotan II, when investigators noticed effects on sexual arousal that were separate from the tanning the compound was originally studied for. Palatin Technologies refined it into PT-141 and carried it through a clinical program that progressed from early intranasal studies to the subcutaneous formulation that ultimately reached approval.
Bremelanotide activates melanocortin-4 receptors (MC4R) in the hypothalamus, a region central to sexual motivation. Preclinical and pharmacology work links this MC4R activity to dopamine signaling in pathways that govern the desire, or appetitive, component of sexual behavior rather than the purely physical response.
A 2022 functional MRI study in women with HSDD found that an MC4R agonist altered activity in brain regions that process sexual stimuli, providing direct human evidence that the effect originates centrally. This contrasts with PDE5 inhibitors such as sildenafil, which act peripherally on the nitric oxide and cGMP pathway to support blood flow.
After a 1.75 mg subcutaneous dose, bremelanotide reaches peak plasma concentration at a median of about 1 hour with absolute bioavailability near 100%, and has a terminal half-life of roughly 2.7 hours. As a small peptide it is cleared by hydrolysis of its amide bonds, which fits the on-demand, take-as-needed dosing model.
Desire, reignited from within
Bremelanotide is a melanocortin receptor agonist that activates MC4R in the hypothalamus, engaging dopamine-linked circuits that drive sexual desire and motivation. Unlike PDE5 inhibitors, which act on peripheral vasodilation, it addresses desire at its neurological source. Its broader melanocortin activity (including MC1R) explains the skin-pigmentation effect seen at higher or more frequent dosing.
Over 24 weeks, bremelanotide 1.75 mg significantly improved the FSFI desire-domain score (integrated effect 0.35, P<.001) and reduced sexual-desire-related distress on FSDS-DAO item 13 (integrated effect -0.33, P<.001) versus placebo.
Kingsberg SA, Clayton AH, Portman D, et al. · Obstet Gynecol, 134(5):899-908 (2019) · PubMed
Desire improvements were sustained through the open-label phase with no new safety signals. The most common adverse events remained nausea, flushing, and headache, which tended to lessen over time.
Simon JA, Kingsberg SA, Portman D, et al. · Obstet Gynecol, 134(5):909-917 (2019) · PubMed
Identified 1.75 mg subcutaneous as the dose carried into Phase 3, with improvements in the number of satisfying sexual events and in sexual function measures relative to placebo.
Clayton AH, Althof SE, Kingsberg SA, et al. · Womens Health (Lond), 12(3):325-37 (2016) · PubMed
A single intranasal dose of bremelanotide, an alpha-MSH analog active at MC3R and MC4R, improved the subjective sexual response, an early signal from the intranasal development program that preceded the subcutaneous formulation.
Diamond LE, Earle DC, Heiman JR, et al. · J Sex Med, 3(4):628-638 (2006) · PubMed
Subcutaneous PT-141 produced statistically significant erectile responses at doses above 1.0 mg, including in sildenafil non-responders, and was reported as safe and well tolerated. This is exploratory data; bremelanotide is not approved for men.
Rosen RC, Diamond LE, Earle DC, et al. · Int J Impot Res, 16(2):135-42 (2004) · PubMed
start low, go slow
Subcutaneous (FDA-approved, Vyleesi)
Subcutaneous (FDA-approved, Vyleesi): No more than one dose in any 24 hours; more than 8 doses per month is not recommended.
Dosing is set by a licensed prescriber. The FDA-approved dose is a single 1.75 mg subcutaneous injection into the abdomen or thigh, taken on an as-needed basis.
The duration of effect after a dose varies between individuals, so patients are guided to find their own optimal timing within the 45-minute-or-more window before activity.
Nausea is most pronounced with the first dose and improves for most people by the second; antiemetic therapy is an option for those who want to continue. Bremelanotide may slow gastric emptying and can markedly reduce the absorption of orally administered naltrexone, so that combination is avoided.
In the pooled Phase 3 trials, the most common adverse reactions were nausea (40%), flushing (20%), injection site reactions (13%), and headache (11%), most of them mild to moderate and related to tolerability.
Bremelanotide transiently raises blood pressure (up to about 6 mmHg systolic, 3 mmHg diastolic) and slightly lowers heart rate after each dose, with values returning to baseline within 12 hours. It is contraindicated in uncontrolled hypertension or known cardiovascular disease, and is not recommended for those at high cardiovascular risk.
Liver injury is rare: clinical trials showed no clinically significant lab changes, and the NIH LiverTox database rates bremelanotide as a possible but rare cause of clinically apparent liver injury, with no reported cases of acute liver failure.
| Peptide | Primary Use | Administration | Cycle Length | Key Differentiator |
|---|---|---|---|---|
| PT-141 (Bremelanotide) | Sexual Health | Injection (as-needed) | Ongoing as-needed | The only FDA-approved on-demand HSDD treatment that works centrally through melanocortin and dopamine pathways rather than peripheral blood flow |
| Melanotan 2 | Pigmentation and sexual function (no approved use) | Subcutaneous injection | About 2 weeks in published trials | Non-selective melanocortin agonist that produces tanning, sexual arousal, and appetite suppression together, paired with safety concerns that kept it from approval and led regulators to flag it |
This peptide is an FDA-approved drug available via standard prescription.
FDA-approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. Available via standard prescription.
FDA approved Vyleesi (bremelanotide 1.75 mg injection) for premenopausal women with acquired HSDD
Last verified April 12, 2026. PepHookup tracks public FDA actions. This is not legal or medical advice.
Diamond LE, Earle DC, Rosen RC, Willett MS, Molinoff PB “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, 16(1):51-9 (2004)
Rosen RC, Diamond LE, Earle DC, et al. “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, 16(2):135-42 (2004)
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