--- title: "PT-141 (Bremelanotide): Benefits, Dosage & Side Effects" description: "PT-141 is bremelanotide (Vyleesi). Its exact approved use, how it works in the brain, what the trials found, side effects, and what is unproven for men." canonical: "https://www.vitalsvault.com/peptides/pt-141" last-updated: 2026-08-22 --- # PT-141 (Bremelanotide): Benefits, Dosage & Side Effects > PT-141 is bremelanotide (Vyleesi). Its exact approved use, how it works in the brain, what the trials found, side effects, and what is unproven for men. ![A South Asian couple: a man, 45, heavyset, trimmed silver-flecked beard, kind eyes, and a woman, 45, tall, burgundy chin-length bob, round gold…](https://www.vitalsvault.com/_next/image?url=%2Fpublic-v3%2Fshoot%2Fpeptides%2Fpep-pt141.webp&w=3840&q=75&dpl=shadow-production-f0162cb4d465-40992538108-1) Peptide Guide · Sexual and reproductive health # PT-141 Bremelanotide, Vyleesi PT-141 descends from a peptide built to tan skin, and it ended up as an FDA-approved drug for low desire in premenopausal women. The approval is narrow, and the details matter. [Get early access to peptide care](https://www.vitalsvault.com/peptides-waitlist)[Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans) Free to join · One email when peptide care opens · Most lab results in 3–5 business days Studied forLow sexual desire and erectile function EvidenceFDA-approved Taken asAs prescribed by a clinician Studied forLow sexual desire and erectile function EvidenceFDA-approved Taken asAs prescribed by a clinician ## PT-141, in short PT-141 is the research name for bremelanotide, sold as Vyleesi. It activates melanocortin receptors in the brain, a system tied to pigment, appetite and sexual response. FDA approved it in 2019 for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). It is not indicated for postmenopausal women, for men, or to enhance sexual performance. Trial benefits were real and modest. Medically reviewed by [Robert Lufkin, MD (opens in a new tab)](https://www.robertlufkinmd.com/) Chief Medical Officer, Vitals Vault · Updated October 29, 2026 · 14 sources ## At a glance FDA-approved TypeSynthetic melanocortin receptor agonist (a peptide)[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Also calledBremelanotide, Vyleesi (brand name)[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Acts onMelanocortin receptors, mainly MC1R and MC4R at therapeutic levels[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) FDA-approved forPremenopausal women with acquired, generalized HSDD[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) Not indicated forPostmenopausal women, men, or improving sexual performance[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) FDA statusApproved June 2019 as Vyleesi[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) ## Before you consider PT-141 - Safety Nausea affected 40% of women in the trials. It briefly raises blood pressure, and about 1% had focal skin darkening.[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) [Side effects and safety](https://www.vitalsvault.com/peptides/pt-141#safety) - Legal status FDA approved it as Vyleesi in 2019 for premenopausal women with acquired, generalized HSDD. It is not approved for men, postmenopausal women or sexual performance.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) [FDA status](https://www.vitalsvault.com/peptides/pt-141#fda-status) - How it’s taken A prefilled injector under the skin of the belly or thigh, used as needed before sex, with limits on how often. A prescriber decides.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) [Forms and dosage](https://www.vitalsvault.com/peptides/pt-141#how-taken) ## How does PT-141 work? It acts in the brain rather than on blood flow, and how it helps desire is not fully known. - ### Targets the brain Its targets sit mainly in the brain and spinal cord. In animals it switched on nerve cells in a deep brain region.[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) - ### Not like erection pills Erection pills act on blood vessels. In a 2006 study, women reported more desire with no clear difference in vaginal blood flow.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) - ### The exact way is unknown The FDA label says how it improves low desire in women is unknown.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## PT-141 benefits: what it is studied for The approved use rests on two phase 3 trials of 24 weeks. Results were statistically significant and modest, and one independent analysis questions the measures used. 1. Human study01 ### Sexual desire in HSDD In the RECONNECT trials, women taking bremelanotide had greater increases in sexual desire than placebo (an integrated difference of 0.35 points on the FSFI desire domain).[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019) 2. Human study02 ### Distress about low desire They also had larger reductions in distress related to low desire (an integrated difference of -0.33).[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019) 3. Human study03 ### Long-term follow-up In a 52-week open-label extension with no placebo group, no new safety signals were seen, and improvements were sustained in women who continued.[2](https://www.vitalsvault.com/peptides/pt-141#source-simon-2019) 4. Human study04 ### Satisfying sexual events Women on bremelanotide reported more desire and less distress. The label reports no significant difference from placebo in satisfying sexual events.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## What the research shows FDA-approved 1. 1 · Cells in a labNot cited This guide cites no findings at this level. Shows a mechanism 2. 2 · Animals Studied In animals, PT-141 switched on nerve cells in the hypothalamus, a deep brain region.[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003) Shows an effect in a body 3. 3 · People Studied Two 24-week phase 3 trials in premenopausal women raised desire 0.35 points and cut distress 0.33 points vs placebo. The effects were modest.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019) Shows it works in people The evidence for the approved use is strong by drug-approval standards and modest in effect size. Studies in men with erectile dysfunction were early-phase and led to no approval. Use in men is not an indicated use.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022)[4](https://www.vitalsvault.com/peptides/pt-141#source-spielmans-2024)[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004) The full guide to PT-141 10 min read · Medically reviewed by Robert Lufkin, MD ## From a tanning experiment to a desire drug In the 1990s, a team at the University of Arizona was chasing a sunless tan. They had designed melanotan I and melanotan II, lab-made relatives of alpha-MSH, the hormone that tells pigment cells to darken the skin. The hope was a tan without the ultraviolet damage. Melanotan II went into a pilot safety study in Tucson, just three men, single-blind, alternating daily injections of drug and saline. In two of them it did darken the skin. It also did something nobody had designed it for. The study recorded a stretching and yawning complex that seemed to arrive together with spontaneous erections, which came and went for one to five hours after a dose. Mild nausea appeared at most dose levels, an early preview of the side effect that would follow this family of molecules for decades. By 1998 the Arizona group was testing melanotan II on purpose. In a placebo-controlled crossover study of 10 men with erectile dysfunction of no known organic cause, 8 developed clinically apparent erections. Nausea, yawning and a dip in appetite were the trade-offs, and none needed treatment. PT-141 came next. Palatin Technologies developed it as a new analogue of melanotan II, and it later took the generic name bremelanotide. The tanning goal was left behind and sexual function became the target. Two decades on, it would become Vyleesi, an injection approved for one specific form of low desire in women.[8](https://www.vitalsvault.com/peptides/pt-141#source-hadley-2006)[9](https://www.vitalsvault.com/peptides/pt-141#source-dorr-1996)[10](https://www.vitalsvault.com/peptides/pt-141#source-wessells-1998)[7](https://www.vitalsvault.com/peptides/pt-141#source-dhillon-2019) ## Why a drug first tested in men was approved for women The first human work with PT-141 itself was in men. In 2003, Palatin researchers reported that it produced erections in rats and monkeys, and that in healthy men and men with erectile dysfunction it caused a rapid, dose-dependent rise in erectile activity. A 2004 placebo-controlled study of a nasal form found erections began about 30 minutes after a dose, with flushing and nausea the most common complaints. Then the work turned to women. In 2006, 18 premenopausal women with sexual arousal disorder took a single dose of bremelanotide and, at another visit, a placebo. More women reported moderate or high sexual desire after the drug. Yet a sensor measuring vaginal blood flow while they watched erotic videos detected no significant difference from placebo. That mismatch is the interesting part. Desire moved and the blood-flow sensor did not, which is consistent with an effect that starts in the brain instead of the plumbing. The later phase 3 trials enrolled women with low desire, and the work in men did not lead to an approval. Palatin ran the phase 3 trials, then licensed North American rights to AMAG Pharmaceuticals, which submitted the new drug application to FDA. Approval came in June 2019 for a self-administered injection used on demand.[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003)[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004)[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006)[7](https://www.vitalsvault.com/peptides/pt-141#source-dhillon-2019)[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## How PT-141 works: a brain signal instead of a blood-flow drug Most people know sexual medicine through erection pills, which act on blood vessels in the penis and need arousal to be under way already. PT-141 starts further upstream. Bremelanotide activates melanocortin receptors, a family of five that the body uses for jobs as different as skin pigment, appetite and sexual behavior. Its label ranks potency as MC1R first, then MC4R, MC3R, MC5R and MC2R, and says binding at MC1R and MC4R is what matters at therapeutic levels. Neurons carrying MC4R are spread through many areas of the brain and spinal cord. In rats, PT-141 switched on neurons in the hypothalamus, in a region wired by nerve pathways to the penis. The label is candid about the rest. It states that the mechanism by which Vyleesi improves HSDD in women is unknown. The receptors are known, and rat studies point to the hypothalamus, but the chain of events from receptor to a change in how much someone wants sex has not been mapped. The timing is short. After an injection, bremelanotide has a half-life of about 2.7 hours, and the label notes that how long the effect lasts after each dose has not been established. It is used as needed before anticipated sexual activity, so it acts as an occasional nudge to a brain circuit and is never meant to build up in the body.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003)[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) ## PT-141 benefits: what the RECONNECT trials found The approval rests on two identical phase 3 trials, studies 301 and 302, known together as RECONNECT. Between 2015 and 2016 they randomized 1,267 premenopausal women with HSDD to bremelanotide or placebo for 24 weeks. The women averaged 39 years of age, 96.6 percent were enrolled at US sites, and 85.6 percent were white. Two outcomes were chosen in advance. One was the desire domain of the Female Sexual Function Index, a questionnaire. The other was a single item asking how much low desire distressed the woman. Across both trials combined, bremelanotide raised the desire score by 0.35 points more than placebo and lowered distress by 0.33 points more. Both differences were statistically significant. A measure that did not move tells you as much. The label reports no significant difference between bremelanotide and placebo in the change in satisfying sexual events, a secondary endpoint. Put plainly, women on the drug reported wanting sex more and minding their low desire less, without a measurable rise in how often they had satisfying sex. Women who finished the core trials could continue in a 52-week open-label extension. Of 856 eligible women, 684 joined and 272 completed it. No new safety signals appeared, and improvements were sustained among those who stayed, a group that by design includes only women who chose to keep going.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[2](https://www.vitalsvault.com/peptides/pt-141#source-simon-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## How big is the benefit? An independent second look In a paper published online in 2023, two psychologists at Metropolitan State University in Minnesota went back to the RECONNECT data and asked whether the questionnaires used actually measure HSDD well in women. They concluded that the desire domain and the distress item have questionable validity evidence for this group, and that the published responder categories had none. They also found that 8 of the 11 efficacy outcomes registered on ClinicalTrials.gov had never been published, including total scores for both questionnaires. When they analyzed those, effect sizes ranged from nil to small. Their summary was that bremelanotide’s benefits are statistically modest and limited to outcomes with scant validity evidence in women with HSDD. Neither reading cancels the other. The phase 3 trials were large, placebo-controlled and positive on their prespecified endpoints, which is why FDA approved the drug. The reanalysis is a reminder that a statistically clear result can still be a small one for any individual woman. The label builds that in, telling prescribers to stop after 8 weeks if she does not report an improvement.[4](https://www.vitalsvault.com/peptides/pt-141#source-spielmans-2024)[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## The tan it never fully lost Remember where PT-141 came from. Its parent molecule was built to darken skin, and MC1R, the receptor bremelanotide activates most potently, is the main switch on the pigment cells that make melanin. The program moved from tanning to desire, but the molecule kept its first talent. It shows up in the safety data. In the phase 3 trials, 1 percent of women using it within the label’s limits developed focal hyperpigmentation, patches of darker skin on the face, gums or breasts. In a separate study where it was given every day for eight days, 38 percent did, and the label notes that the darkening did not clear in some women. That gives a practical rule. Pigment risk climbs with frequency and is higher in darker skin, so the occasional, as-needed pattern the drug was approved for is also the pattern that keeps this side effect rare. Daily use is what raised it most in studies, which is one more reason a self-made schedule is a poor idea. Linking the dark patches to MC1R is our reading of the label’s receptor data, a hypothesis the trials did not test directly. It fits the family history, though. The receptor that made melanotan a tanning candidate is the one bremelanotide hits hardest, and nausea, the other side effect noted in the first melanotan volunteers, has stayed with the family too.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[8](https://www.vitalsvault.com/peptides/pt-141#source-hadley-2006)[9](https://www.vitalsvault.com/peptides/pt-141#source-dorr-1996)[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022) Know your baseline before any peptide 120+ lab tests at Quest Diagnostics, every result reviewed by a licensed clinician. Most results in 3–5 business days. A baseline today gives your clinician something to compare against if you start PT-141 later. [Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans)[Get early access to peptide care](https://www.vitalsvault.com/peptides-waitlist) Full refund before your blood draw · No membership ## PT-141 side effects and safety Nausea is the most common side effect. In the integrated phase 3 data, 40.0 percent of women on bremelanotide reported nausea, against 1.3 percent on placebo. The label says 13 percent needed anti-nausea medicine and 8 percent stopped because of it, and that nausea improved for most women with the second dose. Flushing came next at 20.3 percent, then headache at 11.3 percent and injection site reactions at 5.4 percent. Across the whole development program, 3,500 people took part in 43 completed studies, with no deaths and a few serious adverse events. Most side effects were mild to moderate. Blood pressure deserves a careful look. After each dose, bremelanotide briefly raises blood pressure, by up to 6 mmHg systolic and 3 mmHg diastolic at the peak two to four hours later, and lowers heart rate by up to 5 beats per minute. Both usually return to baseline within 12 hours. The label contraindicates it in uncontrolled high blood pressure and known cardiovascular disease. Two interactions matter. Bremelanotide can slow stomach emptying and change how oral medicines are absorbed, and it can sharply lower blood levels of oral naltrexone, so the label says to avoid it with naltrexone products used for alcohol or opioid addiction. It also advises stopping if pregnancy is suspected and using effective contraception while taking it.[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## PT-141 for men: what was studied, and what was not Because the story began with erections, many men ask whether PT-141 is for them. The early human data were in men. PT-141 produced rapid, dose-dependent erectile responses in healthy men and in men with erectile dysfunction, and in a placebo-controlled study erections began about 30 minutes after a nasal dose. Those were small, early-phase studies, and they did not lead to an approved product for men. The Vyleesi label is explicit on three counts. It is not indicated for HSDD in men, it is not indicated for HSDD in postmenopausal women, and it is not indicated to enhance sexual performance in anyone. That leaves men in a gray zone. The side-effect numbers above, especially nausea and the blood pressure rise, were measured in premenopausal women using the approved product, so they cannot simply be carried over. A vial labeled PT-141 and sold online is a different thing again, with no assurance of what is inside it. Researchers are exploring other routes into the brain’s desire circuitry for men. In a 2023 randomized trial of men with HSDD, a single infusion of kisspeptin, a reproductive hormone, changed activity in the brain’s sexual-processing network and increased penile responses to erotic videos compared with placebo. It is early work, and a separate story.[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003)[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[11](https://www.vitalsvault.com/peptides/pt-141#source-mills-2023) ## Labs worth checking before a low-desire diagnosis HSDD is a diagnosis of exclusion. The label’s definition requires that low desire is not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication. A clinician works through that with your history, medicines and an examination, and blood work fills in the parts a conversation cannot, such as a high prolactin or an underactive thyroid. No blood test diagnoses HSDD. Estradiol and total testosterone describe the sex hormone background. Both shift across the menstrual cycle and with hormonal contraception, so a clinician reads them in context instead of against a single cutoff. Testosterone contributes to desire in women as well as men, but no testosterone level diagnoses HSDD, so a clinician decides whether checking it answers a real question for you. Prolactin is the easy one to miss. A raised level, from a small pituitary growth or from some medicines, can lower desire and gives few other clues without a test. TSH screens the thyroid, since an underactive thyroid can sap energy and libido in ways that look a lot like low desire. This is how Vitals Vault approaches it. A blood panel at Quest Diagnostics comes first, a licensed clinician reviews the results with your history, medicines and blood pressure, and any prescription decision comes after the reversible causes have been looked for.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## PT-141 FDA approval: exactly what it covers FDA approved bremelanotide as Vyleesi under NDA 210557 on June 21, 2019. The indication is the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder, characterized by low sexual desire that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication or drug substance. Acquired means the low desire developed in someone who previously had no problems with desire. Generalized means it happens regardless of the type of stimulation, situation or partner. The label then sets limits of use. Vyleesi is not indicated for HSDD in postmenopausal women or in men, and it is not indicated to enhance sexual performance. The approval belongs to a specific product, a prefilled autoinjector, tested in the trials described here. Products sold online under the name PT-141 are not that product and were not part of the approval.[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## What this means for you PT-141 is one of the few peptides with a full drug-approval story behind it: a tanning experiment, a surprise in the side-effect notes, a pivot from men to women, and two large trials that showed a real but modest lift in desire and a drop in distress. It works in the brain, its side effects are predictable, and its skin effects still recall where it came from. If you are a premenopausal woman whose desire has faded and it bothers you, the first question is what changed. Hormones, thyroid, prolactin, medicines, sleep, mood and the relationship all come before a prescription. If those check out, the next question worth asking your clinician is how the two of you will judge, at 8 weeks, whether it is working.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[4](https://www.vitalsvault.com/peptides/pt-141#source-spielmans-2024)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Know your baseline before any peptide 120+ lab tests at Quest Diagnostics, every result reviewed by a licensed clinician. Most results in 3–5 business days. A baseline today gives your clinician something to compare against if you start PT-141 later. [Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans)[Get early access to peptide care](https://www.vitalsvault.com/peptides-waitlist) Full refund before your blood draw · No membership ## What to expect with PT-141 A prescription starts with a clinician confirming HSDD and ruling out other causes, from hormones and thyroid to medicines and mood. Vyleesi is injected as needed before anticipated sexual activity, and the label notes that how long each dose keeps working has not been established. Nausea is most common after the first injection and improved for most women with the second. Benefit, when it comes, is judged over weeks. RECONNECT measured change over 24 weeks, and the label tells prescribers to stop after 8 weeks if a woman does not report an improvement. Knowing that checkpoint in advance makes the trial a fair test for both of you.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019) ## Key PT-141 studies - Dorr et al., 1996[9](https://www.vitalsvault.com/peptides/pt-141#source-dorr-1996) Pilot phase I study · Volunteers given melanotan II, the parent molecule Darkened skin in some; spontaneous erections and mild nausea also recorded Limits: Three men, single-blind, and a different molecule - Wessells et al., 1998[10](https://www.vitalsvault.com/peptides/pt-141#source-wessells-1998) Placebo-controlled crossover · 10 men with erectile dysfunction of no known organic cause 8 of 10 had erections on melanotan II Limits: Melanotan II, not PT-141; very small - Diamond et al., 2004[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004) Placebo-controlled trials of a nasal form · Healthy men and men with erectile dysfunction Erections began about 30 minutes after a dose; flushing and nausea most common Limits: Early phase; did not lead to approval for men - Diamond et al., 2006[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) Placebo-controlled crossover, single dose · 18 premenopausal women with sexual arousal disorder More reported moderate or high desire; no significant difference in vaginal blood flow versus placebo Limits: Small, one dose, different diagnosis from the approval - Kingsberg et al., 2019 (RECONNECT)[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Two phase 3 randomized trials, 24 weeks · 1,267 premenopausal women with HSDD Desire up 0.35 points and distress down 0.33 points versus placebo Limits: Modest effects; no difference in satisfying sexual events - Simon et al., 2019[2](https://www.vitalsvault.com/peptides/pt-141#source-simon-2019) 52-week open-label extension · 684 women entered, 272 completed No new safety signals; improvements sustained in those who continued Limits: No placebo group; heavy dropout - Clayton et al., 2022[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022) Safety review of the full program · 3,500 people in 43 completed studies Nausea 40.0% vs 1.3%; brief blood pressure rise; rare skin darkening at label use Limits: Authors linked to the developers - Spielmans and Ellefson, 2024[4](https://www.vitalsvault.com/peptides/pt-141#source-spielmans-2024) Independent reanalysis · RECONNECT trial data Benefits statistically modest; outcome measures have scant validity evidence Limits: Reanalysis, not a new trial Key studies on PT-141 | Study | Design | Who | What it found | Limits | | --- | --- | --- | --- | --- | | Dorr et al., 1996[9](https://www.vitalsvault.com/peptides/pt-141#source-dorr-1996) | Pilot phase I study | Volunteers given melanotan II, the parent molecule | Darkened skin in some; spontaneous erections and mild nausea also recorded | Three men, single-blind, and a different molecule | | Wessells et al., 1998[10](https://www.vitalsvault.com/peptides/pt-141#source-wessells-1998) | Placebo-controlled crossover | 10 men with erectile dysfunction of no known organic cause | 8 of 10 had erections on melanotan II | Melanotan II, not PT-141; very small | | Diamond et al., 2004[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004) | Placebo-controlled trials of a nasal form | Healthy men and men with erectile dysfunction | Erections began about 30 minutes after a dose; flushing and nausea most common | Early phase; did not lead to approval for men | | Diamond et al., 2006[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) | Placebo-controlled crossover, single dose | 18 premenopausal women with sexual arousal disorder | More reported moderate or high desire; no significant difference in vaginal blood flow versus placebo | Small, one dose, different diagnosis from the approval | | Kingsberg et al., 2019 (RECONNECT)[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) | Two phase 3 randomized trials, 24 weeks | 1,267 premenopausal women with HSDD | Desire up 0.35 points and distress down 0.33 points versus placebo | Modest effects; no difference in satisfying sexual events | | Simon et al., 2019[2](https://www.vitalsvault.com/peptides/pt-141#source-simon-2019) | 52-week open-label extension | 684 women entered, 272 completed | No new safety signals; improvements sustained in those who continued | No placebo group; heavy dropout | | Clayton et al., 2022[3](https://www.vitalsvault.com/peptides/pt-141#source-clayton-2022) | Safety review of the full program | 3,500 people in 43 completed studies | Nausea 40.0% vs 1.3%; brief blood pressure rise; rare skin darkening at label use | Authors linked to the developers | | Spielmans and Ellefson, 2024[4](https://www.vitalsvault.com/peptides/pt-141#source-spielmans-2024) | Independent reanalysis | RECONNECT trial data | Benefits statistically modest; outcome measures have scant validity evidence | Reanalysis, not a new trial | ## PT-141 myths and evidence - ### PT-141 is just a female Viagra It works differently. Erection pills act on blood vessels, while bremelanotide activates melanocortin receptors in the brain. In a 2006 study, women reported more desire, with no significant difference from placebo in vaginal blood flow. The label says its exact mechanism in HSDD is unknown.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) - ### PT-141 is approved for anyone with low libido The approval covers premenopausal women with acquired, generalized HSDD only. The label states it is not indicated for postmenopausal women, for men, or to enhance sexual performance.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) - ### PT-141 and Melanotan II are the same thing They are related but different. PT-141 was developed as a new analogue of melanotan II, which was designed for tanning. Bremelanotide went through phase 3 trials and FDA approval; melanotan II did not.[8](https://www.vitalsvault.com/peptides/pt-141#source-hadley-2006)[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) - ### PT-141 means you will have more sex Not in the trials. Women on bremelanotide reported more desire and less distress, but the label reports no significant difference from placebo in the number of satisfying sexual events.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Know your baseline first 120+ lab tests at Quest, every result reviewed by a licensed clinician. Most results in 3–5 business days. [Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans) ## How is PT-141 taken? Vyleesi is a prefilled autoinjector given under the skin of the abdomen or thigh as needed before anticipated sexual activity, with limits on how often it can be used. The label sets the details and a prescriber decides.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## PT-141 dosage For Vyleesi, the FDA label sets one injection under the skin of the belly or thigh, used as needed at least 45 minutes before sex, no more than once in 24 hours, and no more than eight doses a month, stopped after eight weeks if there is no improvement. There is no approved dose for men or any other use. Your clinician sets your dose.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ## Typical PT-141 dosage Vyleesi is labelled as one prefilled autoinjector dose under the skin of the abdomen or thigh, used only as needed before sexual activity, with firm limits on how often. A nasal spray was tested in men in early trials but was never approved. A prescriber decides whether the labelled dose fits you. These are reference doses from FDA labels, studies in people and clinical practice reports, shown for education. They are not a recommendation or a prescription. Your dose, form and schedule should be set by a licensed clinician who knows your history and lab results. Already have a prescribed dose? The [peptide dosage calculator](https://www.vitalsvault.com/peptides/tools/dosage-calculator) turns it into the units to draw on an insulin syringe. - FDA label · Injection under the skin of the abdomen or thigh (autoinjector) 1.75 mg As needed, at least 45 minutes before anticipated sexual activity; no more than 1 dose in 24 hours; more than 8 doses per month not recommended[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) Premenopausal women with acquired, generalized HSDD. Stop after 8 weeks if symptoms do not improve. - Human trial · Nasal spray (investigational, never approved) Single doses tested; erections above placebo at doses greater than 7 mg Single dose per study session[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004) Healthy men and men with mild-to-moderate erectile dysfunction who responded to sildenafil (Viagra). No maximum tolerated dose was identified. Typical PT-141 doses in people, by source | Source | Form | Amount | How often | Notes | | --- | --- | --- | --- | --- | | FDA label[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) | Injection under the skin of the abdomen or thigh (autoinjector) | 1.75 mg | As needed, at least 45 minutes before anticipated sexual activity; no more than 1 dose in 24 hours; more than 8 doses per month not recommended | Premenopausal women with acquired, generalized HSDD. Stop after 8 weeks if symptoms do not improve. | | Human trial[6](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2004) | Nasal spray (investigational, never approved) | Single doses tested; erections above placebo at doses greater than 7 mg | Single dose per study session | Healthy men and men with mild-to-moderate erectile dysfunction who responded to sildenafil (Viagra). No maximum tolerated dose was identified. | ## Is PT-141 right for you? A clinician makes the call. These are the questions they will ask first. ### It may suit - Premenopausal women with acquired, generalized HSDD who have had other causes reviewed with a clinician - People who want hormone, thyroid and prolactin labs reviewed before deciding on treatment ### Talk to a clinician first if you are - Uncontrolled high blood pressure or known cardiovascular disease, which are contraindications on the label - Pregnant, or planning pregnancy. The label advises stopping if pregnancy is suspected and using effective contraception - Breastfeeding - Taking oral naltrexone, which the label says to avoid with Vyleesi - Darker skin or frequent dosing, which raise the risk of lasting skin darkening - Any use in men, which is not an approved indication Vitals Vault peptide care starts with a blood panel and a licensed clinician, and ends with a retest. [Get early access to peptide care](https://www.vitalsvault.com/peptides-waitlist) ## PT-141 vs Melanotan II PT-141 vs Melanotan II | Attribute | PT-141 | Melanotan II | | --- | --- | --- | | Molecule | Bremelanotide, a single defined peptide | Melanotan II, a different peptide | | FDA status | Approved as Vyleesi for one use | Not approved, on FDA’s safety-risk list | | Studied for | Low desire in women, erectile function in men | Tanning and erectile function | ## Desire lives in the brain, hormones and relationship together Sexual desire is not a single switch. HSDD is diagnosed only after other causes are considered, and the Vyleesi label excludes low desire explained by another medical or psychiatric condition, relationship problems or a medication. So a clinician starts by looking for contributors that can be corrected, including thyroid, sex hormone, prolactin and medicine effects, before a prescription is considered.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label) ### What else moves the same system 1. 01Review medicinesLow desire caused by a drug effect is excluded from the approved use, so a prescriber can review what you take. 2. 02Check hormones and thyroidA clinician may check estradiol, testosterone, prolactin or TSH when your history points that way. 3. 03Look at mood and relationshipMood and the relationship are part of an HSDD work-up. 4. 04Check blood pressureThe label contraindicates use with uncontrolled high blood pressure or known cardiovascular disease. ## Labs to check with PT-141 A blood test before you start and a retest after shows what actually changed for you. It is how Vitals Vault approaches every treatment. 1. TestA baseline panel at Quest Diagnostics. 2. DecideA licensed clinician reviews your history and results. 3. RetestThe same markers again, side by side. [Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans) - [EstradiolA low or unbalanced level can change desire and is part of an HSDD work-up.](https://www.vitalsvault.com/biomarkers/estradiol) - [Total testosteroneTestosterone contributes to sexual desire in women and men.](https://www.vitalsvault.com/biomarkers/testosterone-total) - [ProlactinHigh prolactin can lower desire.](https://www.vitalsvault.com/biomarkers/prolactin) - [TSHThyroid problems often show up as low energy and low libido.](https://www.vitalsvault.com/biomarkers/tsh) ## Is PT-141 FDA approved? Yes, for one use. FDA approved bremelanotide, sold as Vyleesi, in June 2019 for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder, as characterized by low sexual desire that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication or drug substance. Its label states it is not indicated for postmenopausal women or men, or to enhance sexual performance.[13](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-label)[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) ### PT-141 timeline 1. 2003 Early work describes PT-141 as a melanocortin agonist producing erectile activity in men.[12](https://www.vitalsvault.com/peptides/pt-141#source-molinoff-2003) 2. 2006 Small trial in premenopausal women with sexual arousal disorder reports more moderate or high desire after bremelanotide.[5](https://www.vitalsvault.com/peptides/pt-141#source-diamond-2006) 3. June 2019 FDA approves bremelanotide as Vyleesi for premenopausal women with acquired, generalized HSDD.[14](https://www.vitalsvault.com/peptides/pt-141#source-vyleesi-fda) 4. November 2019 The RECONNECT phase 3 trials and their 52-week extension are published in Obstetrics and Gynecology.[1](https://www.vitalsvault.com/peptides/pt-141#source-kingsberg-2019)[2](https://www.vitalsvault.com/peptides/pt-141#source-simon-2019) ![An East Asian man, 67, small, bald, white goatee, rimless glasses reads on a temple-garden bench](https://www.vitalsvault.com/_next/image?url=%2Fpublic-v3%2Fshoot%2Fpeptides%2Ffaq-pt141.webp&w=3840&q=75&dpl=shadow-production-f0162cb4d465-40992538108-1) ## PT-141 questions What is PT-141 used for? PT-141 is bremelanotide, sold as Vyleesi. FDA approved it for premenopausal women with acquired, generalized hypoactive sexual desire disorder. It was also studied in men with erectile dysfunction, which is not an approved use. What are the benefits of PT-141? In two phase 3 trials, women with HSDD reported greater increases in sexual desire and less distress than on placebo. The differences were statistically significant and modest. How does PT-141 work? It activates melanocortin receptors, mainly MC1R and MC4R at therapeutic levels, with MC4R neurons found across the brain. FDA says the exact mechanism for improving HSDD is unknown. What are the side effects of PT-141? The most common are nausea (40% in trials), flushing, injection site reactions, headache and vomiting. It can briefly raise blood pressure, and about 1% had focal skin darkening. Is PT-141 safe for men? Vyleesi is not indicated for men. Small early studies explored it for erectile dysfunction in men, but no approval followed. Talk with a clinician, and avoid products of unknown content sold online. PT-141 vs Melanotan II, what is the difference? They are related but different peptides. PT-141 was developed as a new analogue of melanotan II, a tanning candidate. PT-141 (bremelanotide) is FDA-approved as Vyleesi for one use. Melanotan II is not approved and appears on FDA’s list of compounding substances with significant safety risks. What is the PT-141 dosage? For Vyleesi, the FDA label sets one injection under the skin, as needed at least 45 minutes before sex, no more than once in 24 hours and no more than eight times a month. There is no approved dose for men or other uses. Your clinician sets your dose. Is PT-141 FDA approved? Yes, as bremelanotide (Vyleesi), since June 2019, for premenopausal women with acquired, generalized HSDD. It is not approved for men, postmenopausal women or to enhance sexual performance. Can I get PT-141 through Vitals Vault? Vitals Vault is opening clinician-led peptide care that starts with a blood test. Join the peptides waitlist to hear first. A licensed clinician reviews your history and labs and decides whether a treatment is right for you. ## Peptides, prescribed and measured Vitals Vault is opening peptide care that starts with your blood work, is prescribed by licensed US clinicians and ends with a retest. Join the waitlist to hear first. - Prescription only - Licensed US clinicians - Quest Diagnostics labs [Get early access to peptide care](https://www.vitalsvault.com/peptides-waitlist)[Start with 120+ lab tests · $99](https://www.vitalsvault.com/labs#plans) ## Keep reading [Full Peptide Guide](https://www.vitalsvault.com/peptides) - Melanotan IIA synthetic melanocortin peptide that darkens skin and affects sexual function. Unapproved, with documented safety reports. - Melanotan IA synthetic version of the pigment hormone alpha-MSH, studied for tanning. As afamelanotide, the same peptide is a prescription implant for one rare disease. - Kisspeptin-10The shortest active piece of kisspeptin, the brain signal that switches on the reproductive hormone axis. - FDA peptide update 2026What FDA’s October 2026 decision on six peptides means for you. - GonadorelinSynthetic GnRH, the hypothalamic signal that tells the pituitary to release LH and FSH. ## Sources 1. 1. [Kingsberg SA, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol. 2019 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/31599840/) 2. 2. [Simon JA, et al. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstet Gynecol. 2019 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/31599847/) 3. 3. [Clayton AH, et al. Safety Profile of Bremelanotide Across the Clinical Development Program. J Womens Health (Larchmt). 2022 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/35147466/) 4. 4. [Spielmans GI, et al. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. J Sex Res. 2024 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/36809187/) 5. 5. [Diamond LE, et al. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist. J Sex Med. 2006 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/16839319/) 6. 6. [Diamond LE, et al. 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. 2004 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/14963471/) 7. 7. [Dhillon S, et al. Bremelanotide: First Approval. Drugs. 2019 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/31429064/) 8. 8. [Hadley ME, et al. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides. 2006 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/16412534/) 9. 9. [Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci. 1996 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/8637402/) 10. 10. [Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol. 1998 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/9679884/) 11. 11. [Mills EG, et al. Effects of Kisspeptin on Sexual Brain Processing and Penile Tumescence in Men With Hypoactive Sexual Desire Disorder: A Randomized Clinical Trial. JAMA Netw Open. 2023 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/36735255/) 12. 12. [Molinoff PB, et al. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003 (opens in a new tab)](https://pubmed.ncbi.nlm.nih.gov/12851303/) 13. 13. [DailyMed. VYLEESI (bremelanotide) injection, prescribing information (opens in a new tab)](https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf) 14. 14. [Drugs@FDA. VYLEESI (bremelanotide), NDA 210557, original approval June 21, 2019 (opens in a new tab)](https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&ApplNo=210557) Written by the Vitals Vault editorial team, medically reviewed by Robert Lufkin, MD, and updated October 29, 2026. This is general education, not medical advice. None of these peptides is FDA-approved to diagnose, treat, cure or prevent any disease, and compounded medicines are not FDA-reviewed for safety, effectiveness or quality. Talk to a licensed clinician before starting any treatment. --- Canonical HTML: https://www.vitalsvault.com/peptides/pt-141 - [llms.txt](https://www.vitalsvault.com/llms.txt) - [sitemap.xml](https://www.vitalsvault.com/sitemap.xml) - [Developer portal](https://www.vitalsvault.com/developers)