PT-141: What It Is, How It Works, and What the Evidence Shows

PT-141, also called bremelanotide, is a lab-made peptide (a short chain of amino acids, the building blocks of proteins) that acts on signaling switches in the brain rather than on blood flow. It is FDA-approved for one use only, as of October 2026: a prescription injection sold as Vyleesi for premenopausal women who have ongoing low sexual desire that causes them real distress. It is not approved for men or postmenopausal women. The nasal sprays and “research” vials sold online are not FDA-approved products.

The rest of this page covers what PT-141 is, how it differs from Viagra, what the clinical trials found in women, what’s known about men, the side effects on the label, and where people actually get it. That last part matters more than most pages admit.

Part of: sexual health peptides

What PT-141 is

PT-141 is the research code name for bremelanotide. Vyleesi is the brand name of the one FDA-approved product made from it. All three names refer to the same molecule. The difference that matters is which product you’re talking about, and that comes up throughout this page.

Bremelanotide belongs to a group of compounds that work on melanocortin receptors. These are switches on cells that the body uses for several jobs, including skin pigment, appetite, and sexual desire. It came out of the same line of research as an earlier lab-made compound called Melanotan II, which is sold as a “tanning peptide” and has a very different regulatory status (more on that below).

Approved vs. not: the one-table answer

The biggest source of confusion online is treating every product called “PT-141” as the same thing. The molecule may be the same. The approval is not. FDA approval covers one specific product, made by one specific manufacturer, for one specific group of patients.

Some people argue that calling the online product “unapproved” is too cautious, since it’s the same molecule FDA already signed off on. The first half of that is true. The molecule is the same. But FDA’s approval doesn’t cover the molecule in the abstract. It covers Vyleesi as made and tested, at its labeled strength, for the women it was studied in. That doesn’t make compounded bremelanotide unsafe or unlawful. It means its status is an open question, and FDA hasn’t answered it publicly.

How it works

PT-141 works in the brain, not in the blood vessels. According to the FDA label, bremelanotide switches on several melanocortin receptors. The two that matter most at the approved dose are MC4R, which is found in the brain, and MC1R, which sits on the skin’s pigment-making cells.

Here’s the part most pages leave out: the label says plainly that the way Vyleesi improves low sexual desire in women “is unknown.” Researchers know which receptors it acts on. They haven’t pinned down exactly how that turns into more desire. (Vyleesi label, DailyMed)

That’s also why “Is PT-141 better than Viagra?” doesn’t have a clean answer. They do different jobs. Viagra-type drugs (sildenafil and its relatives) mainly help blood flow so the body can respond physically. Bremelanotide is aimed at desire itself, through the brain. No trial we’ve found tested the two head to head, so neither one can honestly be called “better.”

The MC1R connection explains one of its side effects. Switching on those pigment cells can darken patches of skin, which is covered in the safety section below.

What the evidence shows in women

Vyleesi was approved based on two identical phase 3 trials called RECONNECT. Phase 3 is the large, late-stage testing a drug has to pass before approval. A total of 1,267 premenopausal women with long-lasting low desire were randomly assigned to bremelanotide or a placebo (a dummy injection) for 24 weeks. Neither the women nor their doctors knew who was getting which. The women were mostly white (85.6%), mostly at U.S. sites (96.6%), and 39 years old on average. (Kingsberg et al., Obstetrics & Gynecology, 2019; FDA Drug Trials Snapshot)

The trials measured two main things: how much desire the women reported, and how much their low desire bothered them. Here are the results, so you can judge them yourself:

• Desire: On a questionnaire score that runs from 1.2 to 6.0, women on bremelanotide improved by about 0.35 points more than women on placebo, with both studies combined.
• Distress: On a 0-to-4 scale of how much low desire bothered them, women on bremelanotide improved by about 0.33 points more than placebo.
• Satisfying sexual events: This was a secondary goal, meaning a less important measure the trials also tracked. The label reports no significant difference between bremelanotide and placebo in the number of satisfying sexual events. (Vyleesi label, Section 14)

Both main results were “statistically significant” in both trials. That means they were very unlikely to be a fluke. It does not mean the change was large. An independent review by two clinical pharmacists concluded that “the clinical benefit may only be modest” (Mayer & Lynch, Annals of Pharmacotherapy, 2020), and the numbers above are why. Women on the drug did report more desire and less distress than women on placebo, by a fraction of a point on each scale. Over the same period, they did not report more satisfying sexual encounters.

The strongest case on the other side is that an average hides individual responses. The trials also judged each woman against preset “responder” cutoffs, meaning the amount of change counted as a real improvement for one person: a rise of at least 1.2 points in desire and a drop of at least 1 point in distress (Vyleesi label, Section 14). The developer’s researchers based those cutoffs on what women in an earlier trial said felt like a meaningful benefit, and several of that paper’s authors worked for the developer, Palatin Technologies (Althof et al., Journal of Sexual Medicine, 2019). That argument holds up as far as it goes: a small average can include some women who get a bigger benefit. It doesn’t change the size of the average difference between the drug and placebo.

The trials were paid for by the companies that developed the drug. The paper lists its funding as Palatin Technologies and AMAG Pharmaceuticals, and FDA lists AMAG as the sponsor. (PubMed 31599840; FDA Drug Trials Snapshot) Industry funding is common for drug approval trials. It doesn’t make the results wrong, but you should know it.

According to the label, 684 of the women went on to a 52-week open-label extension, where everyone knew they were getting the real drug. (Vyleesi label)

What the evidence shows in men

There is no FDA-approved use of bremelanotide in men, as of October 2026. The Vyleesi label says directly that it “is not indicated for the treatment of HSDD in postmenopausal women or in men.” (Vyleesi label)

Researchers did study bremelanotide in men during its earlier development, and that work is the strongest case that it does something in men. In a small placebo-controlled study published in 2004, an early nasal-spray version produced erections more often than placebo in healthy men and in men with mild-to-moderate erectile dysfunction (trouble getting or keeping an erection), measured with a device in a clinic. Three of the paper’s five authors worked for Palatin Technologies, the drug’s developer. (Diamond et al., International Journal of Impotence Research, 2004)

A second 2004 study, of an injected version, reported the same kind of response, including in men who hadn’t responded well to Viagra. (International Journal of Impotence Research, 2004) Palatin itself says bremelanotide has been tested in men with erectile dysfunction “in numerous clinical studies” with significant improvements, which is the developer describing its own drug. (Palatin press release, August 2023)

Here is where that argument is right: no approval for men is not the same as proof it does nothing in men, and these early studies did measure an effect. Here is where it falls short: they were small, short, early-stage studies that measured erections in a clinic, not large trials of how men do over months in real life. Personal reports from men who use it today can’t fill that gap either. They can’t tell you what the drug does across many men, how often, or at what cost in side effects. That’s what large controlled trials are for, and none has led to an approval for men. So we can’t honestly tell you what PT-141 will do for you if you’re a man. Anyone who tells you confidently that it will is going past the evidence.

Safety and who should not use it

The safety details below come straight from the FDA label. They aren’t softened and they aren’t dramatized. (Vyleesi label, DailyMed)

Who should not use it. The label says Vyleesi should not be used by people with uncontrolled high blood pressure or known cardiovascular disease, meaning disease of the heart or blood vessels. It also says Vyleesi “is not recommended for patients at high risk for cardiovascular disease.”

Blood pressure and heart rate. After each dose, blood pressure goes up for a while and heart rate goes down. In the trials, the top blood-pressure number rose by up to 6 points and the bottom number by up to 3 points, peaking 2 to 4 hours after a dose. Heart rate dropped by up to 5 beats per minute. Both usually returned to normal within 12 hours.

Some people argue the blood-pressure warning is overblown for healthy users, since the rise is small and goes away. The label’s numbers back up that the average change is small and temporary. A 2022 review of safety data from across the drug’s development, written by trial investigators that included employees of the companies that developed and marketed it, called the rises “small and transient” and said they weren’t considered clinically important. The same review still advised caution for people at risk of heart disease. (Clayton et al., Journal of Women’s Health, 2022)

The label also still lists heart disease and uncontrolled high blood pressure as reasons not to use it. Both of those things are true, and you should weigh them with a doctor who knows your heart health.

Nausea. This is the most common side effect by far. 40% of women in the phase 3 trials had nausea, compared with 1.3% on placebo. 13% needed anti-nausea medicine, and 8% stopped the drug because of it. It was most common after the first dose (21% of women) and much less common after later doses (about 3%).

Other common side effects (bremelanotide vs. placebo):

Overall, 18% of women on bremelanotide quit the trials because of side effects, compared with 2% on placebo.

Skin darkening. Some people get darker patches of skin on the face, gums, or breasts. The label calls this focal hyperpigmentation. It happened in 1% of trial patients, compared with none on placebo. In a separate study with repeated daily use, 38% developed it. People with darker skin were at higher risk, and the patches didn’t clear up in every case.

Interactions with other medicines. The label says bremelanotide can slow how fast your stomach empties. That can affect how well some medicines you swallow are absorbed. The label also says not to use it with naltrexone taken by mouth (a medicine used for alcohol or opioid dependence), because bremelanotide can sharply lower naltrexone levels.

Pregnancy. The label advises using effective birth control while on Vyleesi and stopping it if you think you might be pregnant.

All of these numbers come from the approved product, at its approved dose, in the women who were studied. We found no published trials of compounded or “research” PT-141 products, so there’s no data showing these numbers carry over to them.

PT-141 vs. Melanotan II

PT-141 and Melanotan II get mixed up a lot, partly because they come from the same family of research and act on some of the same receptors. Their regulatory status is very different.

For the full picture on Melanotan II, see our Melanotan II entry. Its live status is tracked in the Regulatory Tracker.

Where people actually get it: an honest look at availability

PT-141 reaches people through four different channels, and each one gives you very different guarantees. The fact that something can be bought online tells you nothing about whether it’s what it claims to be, or whether it’s right for you.

A prescription for Vyleesi, filled at a licensed pharmacy. This is the only route to the FDA-approved product. A licensed prescriber writes it, sometimes after a telehealth visit, and a regular pharmacy fills it. What you get: a product FDA has reviewed for manufacturing quality and labeled strength, plus a prescriber who is supposed to check your heart health and other medicines first. What you don’t get: approval for any use outside the label. Doctors are generally allowed to prescribe an approved drug off-label, but that use hasn’t been through FDA’s review.

Compounded bremelanotide, through a compounding pharmacy. Some telehealth and medspa clinics prescribe bremelanotide that a compounding pharmacy custom-makes. What you get: a licensed pharmacist who is accountable for what goes in the vial, and a prescriber involved. What you don’t get: an FDA-approved product. Compounded drugs don’t go through FDA’s approval review.

The compounding industry’s trade group, the Alliance for Pharmacy Compounding, argues this route is much safer than the unregulated market. In a July 2026 letter to FDA, it said state-licensed pharmacies must follow USP standards (the official U.S. quality rules for compounding) and state pharmacy-board rules and are subject to inspections, while unregulated sellers “offer no guarantees of identity, purity, potency, or sterility.” (APC letter to FDA, July 9, 2026) That’s an industry group making the case for its own members, and the letter doesn’t mention bremelanotide. Its point about added oversight matches the basic difference between these channels. It doesn’t make a compounded product FDA-approved, and it doesn’t settle whether bremelanotide can be compounded.

Whether bremelanotide can be compounded at all is genuinely unresolved. FDA’s rules for compounding pharmacies (known as Section 503A) generally allow compounding from an ingredient that’s part of an approved drug. The same rules also bar compounding pharmacies from making what amounts to a copy of a drug that’s already on the market. Bremelanotide isn’t on any of FDA’s 503A category lists (FDA). FDA.gov has no specific statement on whether compounding it is allowed. Sources outside FDA disagree with each other. If you’re considering this route, it’s a fair question to put to the compounding pharmacist directly.

Telehealth and medspa clinics. Clinics are a storefront, not a separate kind of product. Depending on the clinic, a prescription might be for Vyleesi or for a compounded version, and that difference matters for everything above. Ask which one you’d be getting.

“Research use only” websites. Many sites sell PT-141 vials and nasal sprays straight to consumers, labeled “not for human consumption.” That label is a statement about oversight, not about quality. No prescription, no medical supervision, no FDA manufacturing checks, no required independent check of purity or dose, and no clear legal recourse if something goes wrong.

We don’t recommend or link to any seller on this page. For more on the legal side of peptides in general, see Are Peptides Legal?.

Regulatory status and what could change

Bremelanotide is FDA-approved as Vyleesi for one use, as of October 2026: premenopausal women with acquired, generalized hypoactive sexual desire disorder. FDA approved it on June 21, 2019. It isn’t approved for men, for postmenopausal women, or as a nasal spray. (FDA Drug Trials Snapshot)

You may have read about FDA’s Pharmacy Compounding Advisory Committee, the outside expert panel that advises FDA on which ingredients compounding pharmacies can use. It met July 23–24, 2026 to review seven peptides: BPC-157, KPV, TB-500, MOTs-C, DSIP (emideltide), Semax, and Epitalon. Bremelanotide was not on the list. FDA also notes that these committees make “non-binding recommendations.” Even for the peptides it did review, the committee’s vote is advice to FDA, not a final decision. (FDA PCAC meeting page)

What could change: FDA could clarify whether bremelanotide can be compounded, or nominate it for one of its 503A categories. The approved label could also be updated. We watch for all of these and update the bremelanotide row in our Regulatory Tracker when anything moves.

FAQs about PT 141 peptide