PT-141 (Bremelanotide)

What is PT-141 and how does it act?

Bremelanotide is a synthetic peptide that acts on melanocortin receptors. In an early 2004 human study, PT-141 is described as a cyclic heptapeptide (a ring-shaped peptide of seven amino acids) melanocortin analog. ^[8] According to the US label, bremelanotide stimulates multiple melanocortin receptors without selectivity; at therapeutic doses, binding to MC1 and MC4 receptors is the most important effect. Nerve cells carrying MC4 receptors are found in many regions of the central nervous system; binding to the MC1 receptor on pigment cells increases melanin production and pigmentation. The mechanism by which the drug improves HSDD in women is unknown. ^[1]

Melanotan II, sold without a license for tanning, is also a peptide acting on melanocortin receptors, but it is not the same substance as bremelanotide. Details:

Who is Vyleesi approved for?

The US label defines the approved use narrowly: premenopausal women who have not previously had a sexual desire problem and who experience low desire regardless of circumstance, partner, or type of stimulation. This low desire must cause marked distress or relationship difficulty and must not be explained by a coexisting medical or psychiatric condition, relationship problems, or the effect of a drug or substance. The label states explicitly that the drug is not indicated in postmenopausal women, in men, or for enhancing sexual performance. ^[1]

The drug is a single-use autoinjector administered by the patient under the skin, as needed. The label does not recommend more than one dose within 24 hours or more than 8 doses per month. ^[1] This is prescribing information for physicians, not a recommendation for personal use.

What did the RECONNECT trials show?

In the two identical phase 3 trials that underpin the approval (301 and 302), women diagnosed with premenopausal HSDD were randomized to bremelanotide or placebo for 24 weeks. A total of 1,267 women were randomized; there were 1,247 in the safety analysis and 1,202 in the efficacy analysis. Of the participants, 85.6% were White, 96.6% were from US sites, and the mean age was 39. The trials were funded by the two companies that developed the drug; the authors included company employees. ^[2]

According to the tables in the US label, the mean increase in desire score was 0.5 with bremelanotide and 0.2 with placebo in the first trial, and 0.6 versus 0.2 points in the second. The distress score fell by a mean of 0.7 points with bremelanotide and 0.4 with placebo in both trials. ^[1] In other words, on a scale ranging from 1.2 to 6, the mean difference from placebo is under half a point.

How meaningful is the effect?

Spielmans and Ellefson (Metropolitan State University, psychology department) reported that the evidence for the validity of the scales used in RECONNECT in women with HSDD is “questionable at best,” and that 8 of 11 registered efficacy endpoints had not been published previously. When they analyzed these endpoints, they wrote that effect sizes ranged from “zero to small,” that most of the other positive-looking results were most likely defined after the trials, and that the benefits of bremelanotide were statistically “modest.” ^[6] The manufacturer-supported safety review also reports that the proportion moving from the double-blind period into the open-label extension was 70% in the bremelanotide group and 87% in the placebo group. ^[4]

Long-term use

Of 856 eligible participants who completed the double-blind period, 684 joined the 52-week open-label extension and 272 completed it. The increase in desire score continued during this period and no new safety signal was seen; however, the extension was uncontrolled and all analyses were descriptive. The most common drug-related side effects in this period were nausea (40.4%), facial flushing (20.6%), and headache (12.0%). ^[3]

Side effects and safety

• Nausea: According to the US label, it was the most common side effect in placebo-controlled phase 3 trials (40%); 13% of patients needed anti-nausea medication and 8% left the trial early for this reason. It diminished with the second dose in most patients. ^[1] In the manufacturer-supported safety review, during the double-blind period, nausea occurred in 40.0% versus 1.3%, facial flushing in 20.3% versus 1.3%, and headache in 11.3% versus 1.9%; nausea was the most common reason for discontinuing the drug. ^[4]
• Blood pressure: According to the label, after each dose systolic blood pressure rises by up to 6 mmHg and diastolic by 3 mmHg; the peak is 2–4 hours after the dose, heart rate falls by up to 5 beats per minute, and values mostly return to baseline within 12 hours. Uncontrolled hypertension or known cardiovascular disease is a contraindication; use is not recommended in people at high cardiovascular risk. ^[1] In an ambulatory blood pressure monitoring study of 397 premenopausal women, the increases were 2.4–3.2 mmHg versus placebo and the peak usually lasted less than 15 minutes; the study authors included manufacturer employees. ^[5]
• Focal hyperpigmentation: In phase 3 trials, blotchy darkening of the face, gums, and breasts occurred in 1% of those receiving up to 8 doses per month; in a study with daily use for 8 consecutive days, the rate rose to 38%. The risk was higher in people with darker skin, and resolution after stopping the drug could not be confirmed in all patients. ^[1]
• Drug interactions: Bremelanotide can slow gastric emptying and reduce the absorption of orally administered drugs; because it can markedly lower blood levels of oral naltrexone, avoiding concomitant use is recommended in people using naltrexone for alcohol or opioid dependence. ^[1]
• Pregnancy: The few pregnancies in clinical trials are insufficient for risk assessment; the label recommends stopping the drug if pregnancy is suspected and using an effective contraceptive method during treatment. ^[1]

The clinical development program covers 3,500 people in 43 completed studies. ^[4] These data belong to the licensed product; they cannot be transferred to products whose contents are unverified.

Use in men: what does the evidence say?

Bremelanotide was investigated for erectile dysfunction in men before HSDD in women. These studies did not lead to licensure, and the US label states that the drug is not indicated in men. ^[1]

This evidence does not demonstrate the efficacy and safety of bremelanotide in men at a licensure level. The blood pressure warnings and contraindications in the US label rest on studies in premenopausal women; the label contains no evaluation for use in men. ^[1]

PT-141 sold as a “research peptide”

The name PT-141 is widely used for products sold online labeled “for research purposes.” In a warning letter dated August 24, 2026, the FDA treated an online seller’s “PT-141” product as an unapproved new drug. On the seller’s page, the product was promoted as a peptide “studied” for possible effects on sexual arousal and libido. The FDA wrote that, despite the “for research use only” and “not for human consumption” statements on the product label, the descriptions on the website and the sale of a solvent for injection preparation showed that the products were being sold for use in humans. ^[11]

Such products are not approved Vyleesi: their manufacturing conditions, purity, quantity, and sterility have not been independently verified. The FDA letter stresses that injectable products carry a risk of serious harm because they bypass some of the body’s defenses and reach tissue or blood directly. ^[11] The meaning of the label is covered in a separate guide: What does research peptide mean?

Status in the EU and in sport

The EMA medicines dataset dated October 18, 2026, contains no licensed, withdrawn, or refused application record for bremelanotide; that is, bremelanotide is not a centrally licensed medicine in the EU. ^[7]

The WADA 2026 Prohibited List does not name bremelanotide. The S0 class of the list covers only pharmacological substances that appear nowhere else in the list and are not approved by any governmental health authority for therapeutic use in humans. ^[12] Bremelanotide is an approved drug in the US; nevertheless, because the actual contents of products sold under the “PT-141” label are unknown, these products carry a separate uncertainty for athletes.

What is the status of PT-141 in Türkiye?

The guide covering the legal status of peptides in general: Are peptides legal?

Evidence table: claim, population, and limits

Limits of this guide

This page summarizes published evidence and official documents on bremelanotide. The dosing information in the label is reported only to identify the licensed drug; no personal dose, preparation, administration method, or product source is included. Problems with sexual desire have many medical, psychological, and relationship-related causes, and evaluation addresses these causes with a physician. The information is current as of October 2026.