PT-141 (Bremelanotide): What Lakeland Readers Should Know

PT-141 is the research name for bremelanotide, the active ingredient in the brand-name drug Vyleesi. It is FDA-approved for one narrow use in women. This page explains what it is, what the trials showed, where the evidence is weak, and what to ask before you start. It is general information, not advice for your situation.

What it is and how it works

Bremelanotide is a lab-made peptide: a short chain of seven amino acids joined in a ring.¹ It switches on melanocortin receptors. These cell “docking sites” help control skin color, appetite and sexual response. At the doses used, the two that matter most are MC1R, found on the skin’s pigment cells, and MC4R, found in the brain.¹

The drug label says plainly that how bremelanotide improves low sexual desire in women is unknown. Its action on pigment cells explains why some people develop darker patches of skin.¹

The approved product is a prefilled autoinjector. It is given as an injection under the skin, as needed before expected sexual activity, rather than as a daily medicine.¹

What the research shows (and where evidence is weak)

FDA approval rested on two identical phase 3 trials called RECONNECT. “Phase 3” means a large trial done before approval. These trials were randomized and placebo-controlled: women were assigned by chance to the drug or to a dummy shot, and neither they nor the researchers knew which. The trials enrolled 1,267 premenopausal women with hypoactive sexual desire disorder (HSDD), a diagnosis of low sexual desire that causes distress. The women’s average age was 39, about 86% were white, and almost all were at U.S. sites. Each trial lasted 24 weeks.²

Both trials met their two main goals, but the gains were modest. On a desire score that runs from 1.2 to 6.0, women on the drug improved by about 0.35 points more than women on placebo. On a 0-to-4 score for how much low desire bothered them, distress fell by about 0.33 points more.² A 2026 review that pooled many studies (read as a summary only) also found better desire and arousal scores.³

Important limits:

• No increase in satisfying sex. The number of satisfying sexual events did not go up compared with placebo in either trial.¹
• Large placebo response. About 58% of women on the drug felt they had benefited, but so did about 36% on placebo.² A separate analysis of drug trials for female sexual problems estimated that about two-thirds of the improvement seen with treatment was matched by placebo. That figure pools several drugs, not just bremelanotide.⁴
• More dropouts on the drug. More women stopped early on bremelanotide than on placebo: 40% vs 13% in one trial and 39% vs 25% in the other.¹
• An independent critique. A 2021 re-analysis of the FDA application data found effects similar in size to the company’s. But it argued the benefit is small, that many more women quit because of side effects on the drug, and that participants in effect “preferred placebo.” The company’s authors published a rebuttal.⁵
• Company-run trials. The sponsor designed, ran and analyzed the trials, and the drug’s licensee paid for writing support.² No independent trial of the approved product turned up in this research.
• A narrow group. The results apply to premenopausal women like those studied. They do not show what happens in men, in women after menopause, or for “performance.”
• Men. Evidence in men is small and older. Early company studies tested a nasal form, not the approved shot. One trial of 342 men reported benefit, but that paper has carried an expression of concern since 2023.⁶ A 2026 review of peptides for male sexual problems found the studies small, short and varied.⁷ No phase 3 trial in men was found.

FDA and regulatory status

FDA approved Vyleesi (bremelanotide) on June 21, 2019.⁸ As of November 12, 2026, FDA’s drug database lists it as a prescription autoinjector, with Cosette as the company holding the approval.⁹

The label limits its use to premenopausal women with acquired, generalized HSDD. That means low desire that causes marked distress or relationship difficulty and is not caused by another medical or mental health condition, problems in the relationship, or a medicine or drug. The label says it is not approved for women after menopause or for men, and not to enhance sexual performance.¹ Use in men is therefore off-label.

Some clinics offer compounded versions, made by a pharmacy rather than the drug company. Federal rules let a pharmacy compound with an ingredient that is part of an FDA-approved drug, if other conditions are met.¹⁰ A compounded product is still not FDA-approved, and the trials above did not test it. As of April 22, 2026, bremelanotide was not on FDA’s list of compounding ingredients with significant safety concerns.¹¹

PT-141 is also sold online as a “research chemical.” In August 2026, FDA warned a Sarasota, Florida seller that its “PT-141 (Bremelanotide)” product was an unapproved new drug. FDA said “research use only” labels do not change that when the seller’s website shows the product is meant for people.¹² See our guides to compounded vs. FDA-approved peptides and research chemical peptide risks.

Competitive athletes should check bremelanotide’s status with their anti-doping organization or on WADA’s Prohibited List.¹³

Common side effects and safety

From the drug label:¹

• Nausea was the most common side effect: 40% of women on the drug vs 1% on placebo. It was worst after the first dose, and 8% stopped the trials because of it. Taking an anti-nausea pill beforehand did not help in a later study.
• Flushing (20%) and headache (11%) were also common. Overall, 18% stopped because of side effects, compared with 2% on placebo.
• Blood pressure. Blood pressure rose by up to about 6 points (top number) and 3 points (bottom number) for a few hours after each dose, and heart rate dipped slightly. These usually returned to normal within 12 hours. The drug should not be used by people with uncontrolled high blood pressure or known heart disease, and it is not recommended for people at high risk of heart disease.
• Darker skin patches on the face, gums or breasts occurred in about 1% of women in the main trials. They were much more common in a study where the drug was given every day, and more likely in people with darker skin. They did not always fade after stopping.
• Other points. It can sharply lower blood levels of naltrexone taken by mouth, and it may slow how fast other pills are absorbed. Animal studies showed harm to unborn young, so the label advises effective birth control. One case of liver inflammation (hepatitis) could not be ruled out as drug-related.

Typical cost range

We did not find an official list price for Vyleesi. Cost depends on whether you use the brand-name product or a compounded version, your insurance plan, how often you use it, and any clinic or visit fees. Ask any provider or pharmacy for a written price breakdown before you start.

Ask for a written breakdown of what is included. Our cost guide and insurance and HSA/FSA guide cover what to ask.

Questions to ask a provider

• What could be causing my symptoms? Have we looked at other causes, such as medicines, hormones, mood or relationship factors?
• Am I in the group the FDA-approved product was studied in? If not, what evidence supports using it for me?
• Are you prescribing brand-name Vyleesi or a compounded version? If compounded, which licensed pharmacy makes it?
• Is my blood pressure and heart health safe for this medicine?
• What should I do if I have nausea or notice darker patches of skin?
• How will we decide whether it is working, and when should I stop if it is not?
• What is the total cost, and what does it include?

For more on preparing for an appointment, see our first consultation guide and the sexual health goal page.