What PT-141 Actually Is, Who It Is Approved For, and What the Trials Found

Search PT-141 and you get nine results: a urology clinic, a pharmacy retailer, a PubMed abstract, three telehealth and clinic pages, a Reddit thread, a YouTube video, and — at position nine — Mayo Clinic, which ranks only by using the drug's generic name instead.

Most of those pages sell it. Very few say who it is approved for, and none report the trial result that did not go the drug's way.

The Short Answer

PT-141 is the development name commonly used for bremelanotide. Vyleesi® is the FDA-approved product: a 1.75 mg subcutaneous bremelanotide injection. The names are not interchangeable.

Compounded preparations containing bremelanotide or "PT-141" are not Vyleesi and are not FDA-approved drug products. Everything below — the indication, the dose, the trial results, the safety numbers — describes Vyleesi, not a compounded preparation at some other strength or route.

Vyleesi is approved for one condition in one population: acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. The label states it is not indicated for postmenopausal women or for men.

In two phase 3 trials covering 1,267 women, Vyleesi produced small but statistically significant improvements on a desire questionnaire and a distress questionnaire. The trials did not show a statistically significant increase in the number of satisfying sexual events, a pre-specified secondary endpoint, even though those scores improved.

And the label is candid about something the marketing pages are not: how it works is unknown.

PT-141, Bremelanotide, Vyleesi: What Each Name Refers To

• Bremelanotide is the drug substance — the non-proprietary name for the molecule.
• PT-141 is the development code from that molecule's research history. It is what most people search and what most compounded products are marketed under. It is not a regulatory category and does not specify any strength, route or manufacturer.
• Vyleesi® is the FDA-approved finished product: 1.75 mg of bremelanotide in a single-dose subcutaneous autoinjector, with an approved label and indication.

Only the third has been through FDA review. Compounded preparations are prepared by pharmacies rather than approved as drug products, so the FDA has not evaluated them for safety, effectiveness or manufacturing quality, and no clinical trial data describes them.

So when a page cites "PT-141 trials," it is citing the Vyleesi evidence — a specific 1.75 mg subcutaneous injection in a specific population. Whether those results transfer to a different preparation is not something the trials answer.

What the Label Says Vyleesi Is For

The approved indication is narrower than almost any page describing it suggests. Quoted in full:

"VYLEESI is indicated for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), 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."

Every clause excludes someone. The label defines two of them itself.

• Premenopausal. The label states separately that VYLEESI "is not indicated for the treatment of HSDD in postmenopausal women or in men."
• Acquired. The label's definition: "HSDD that develops in a patient who previously had no problems with sexual desire." The low desire developed after a period of previously satisfactory desire, rather than being lifelong.
• Generalized. The label's definition: "HSDD that occurs regardless of the type of stimulation, situation or partner." Not limited to particular partners, situations or forms of sexual activity.
• Causing marked distress or interpersonal difficulty. Low desire without distress is not the condition being treated.
• Not due to a relationship problem, another condition, or another medication. Those causes are explicitly outside the indication.

The label also states plainly: "VYLEESI is not indicated to enhance sexual performance."

Read the current VYLEESI prescribing information on DailyMed.

A wrinkle worth knowing

The diagnosis on the label is not the term the current psychiatric manual uses for women. The DSM-5, published in 2013, replaced female HSDD with female sexual interest/arousal disorder, merging desire and arousal into one diagnosis.

Many sexual-medicine specialists did not adopt that merger as the only clinically useful framework. The International Society for the Study of Women's Sexual Health published a consensus nomenclature in 2016 that retained HSDD as a standalone diagnosis, on the stated grounds that the DSM-5 definitions "do not identify all sexual problems experienced clinically by women and are not necessarily applicable for biologic or biopsychosocial management."

The label's "acquired, generalized" wording comes from the earlier DSM-IV-TR, and HSDD research still uses those criteria. We could not find a published FDA rationale for the choice, so we report the discrepancy rather than explain it.

How It Is Thought to Work

Bremelanotide is a melanocortin receptor agonist. The label describes it as one that "nonselectively activates several receptor subtypes with the following order of potency: MC1R, MC4R, MC3R, MC5R, MC2R," adding that "at therapeutic dose levels, binding to MC1R and MC4R is most relevant."

MC4R receptors sit on neurons throughout the central nervous system, which is the basis for the widely repeated claim that PT-141 "works on the brain rather than on blood flow."

That claim is an inference, and the label declines to make it. Its mechanism section states: "The mechanism by which VYLEESI improves HSDD in women is unknown."

One clearly established consequence of melanocortin-receptor activity is increased pigmentation through MC1R, which sits on the melanocytes that produce skin pigment; the label notes that "binding at this receptor leads to melanin expression and increased pigmentation." That is the pathway with the least uncertainty attached to it — and it is a side effect, not a benefit.

Research has probed the central hypothesis directly. A 2022 study in the Journal of Clinical Investigation gave bremelanotide 1.75 mg subcutaneously to 31 premenopausal women with HSDD in a randomised, double-blind, placebo-controlled crossover design with functional neuroimaging, reporting increased sexual desire for up to 24 hours and altered brain responses to erotic stimuli. It is a mechanistic study of that size and design — not a third efficacy trial — and it was funded in part by the drug's manufacturer at the time.

How Vyleesi Is Dosed

From the label. These instructions describe Vyleesi specifically; no dosing information exists for compounded bremelanotide preparations.

• 1.75 mg subcutaneously, into the abdomen or thigh, self-administered by autoinjector
• As needed, at least 45 minutes before anticipated sexual activity
• No more than one dose in any 24 hours
• More than eight doses per month is not recommended

One line answers a question readers ask constantly, and the answer is "nobody knows": "The duration of efficacy after each dose is unknown and the optimal window for VYLEESI administration has not been fully characterized."

In the trials, the median number of injections across the whole 24-week period was ten — roughly two or three a month, well under the eight-dose ceiling.

The label sets a stopping point

Section 2.2 is one sentence long, and pages selling the drug rarely quote it: "Discontinue VYLEESI after 8 weeks if the patient does not report an improvement in her symptoms." That is an instruction to the prescriber, and it exists because an as-needed drug can otherwise be continued indefinitely without anyone formally asking whether it is working.

What the Trials Found

Approval rests on two identically designed phase 3 trials of Vyleesi, known as RECONNECT, published in Obstetrics & Gynecology in 2019. Both were randomised, double-blind and placebo-controlled, with a 24-week core period.

1,267 women were randomised, with 1,202 in the efficacy analysis. Mean age was 39. Participants had acquired, generalized HSDD of at least six months' duration. There were two co-primary endpoints.

Desire, measured by questionnaire

On the Female Sexual Function Index desire domain, which runs from 1.2 to 6.0, the placebo-adjusted improvement was:

• Study 1: +0.30 (P < .001)
• Study 2: +0.42 (P < .001)

Distress, measured by questionnaire

On item 13 of the Female Sexual Distress Scale — bother from low desire, scored 0 to 4 — the placebo-adjusted change was:

• Study 1: −0.37 (P < .001)
• Study 2: −0.29 (P = .005)

Both endpoints were met in both trials. Both effects are small in absolute terms. These are average treatment effects; individual responses varied substantially.

The Result That Does Not Appear on Any Page Selling It

Satisfying sexual events — a pre-specified secondary endpoint — did not increase significantly.

• Study 1: mean change 0.0 on bremelanotide against −0.1 on placebo (p = 0.76)
• Study 2: 0.0 against 0.0 (p = 0.70)

Put precisely: the trials did not show a statistically significant increase in the number of satisfying sexual events, even though the desire and distress questionnaire scores improved.

That is not a reason to dismiss the finding — desire and distress are what the condition is defined by, and reducing distress is a legitimate goal in itself. But a reader deciding whether to pursue this treatment is usually asking about their sex life, not about a questionnaire, and on that specific count the trials did not demonstrate a change.

What the Trials Cost Participants

Around four in ten Vyleesi-treated participants left the 24-week trial early.

• Study 1: 40% of the bremelanotide group discontinued prematurely, against 13% on placebo
• Study 2: 39% against 25%
• Discontinuation specifically due to adverse reactions: 18% against 2%

The leading causes of adverse-event dropout were nausea at 8%, headache at 2%, then vomiting, flushing and injection-site reactions at 1% each.

Nausea affected 40.0% of Vyleesi-treated participants overall, against 1.3% on placebo, and was highest after the very first dose, reported by 21%. Full detail: PT-141 Side Effects: Every Number the Label Reports.

The trial authors described the safety profile as favourable. Both statements are in the record; readers deserve to see the numbers behind the adjective.

A Published Disagreement About These Trials

The RECONNECT results are not universally accepted, and a page presenting them as settled would misrepresent the literature.

A 2021 re-analysis by Spielmans in the Journal of Sex Research challenged the trials' reporting practices and clinical meaningfulness. Its criticisms were specific: that a large majority of protocol-listed outcomes went unreported while fifteen secondary measures not listed in the protocols were reported instead; that adverse-event-induced discontinuation was substantially higher on bremelanotide; and that, judged by who completed the trial and then chose to enter the open-label extension, participants tended to prefer placebo. A 2024 follow-up by Spielmans and Ellefson extended the argument to measurement, contending that the desire and distress instruments used have limited published validity evidence in women with HSDD, and analysing outcomes not previously published.

Trial investigators published a response. Kingsberg and colleagues replied in the same journal in 2021, in a commentary titled "Failure of a Meta-analysis."

Separately, a 2021 piece in Drug and Therapeutics Bulletin examined bremelanotide and flibanserin together under the heading of "the fallacy of regulatory precedent" — published criticism of the regulatory evidence base and the decisions built on it, rather than new evidence that the drug does not work.

We report that this exchange exists because any reader researching this drug should know that specialists disagree about how much the trials showed.

What the Label Warns About

Vyleesi does not carry an FDA boxed warning, but it does have important contraindications and warnings.

Contraindications. The section is short enough to quote in full: uncontrolled hypertension or known cardiovascular disease. The label adds that VYLEESI "is not recommended for patients at high risk for cardiovascular disease."

Blood pressure and heart rate. The label reports that VYLEESI "transiently increases blood pressure and reduces heart rate after each dose," with maximal increases of 6 mmHg systolic and 3 mmHg diastolic peaking two to four hours after dosing, and a heart-rate reduction of up to 5 beats per minute, generally returning to baseline within 12 hours.

Focal hyperpigmentation. A labelled warning in its own right, following directly from the MC1R activity above. The label reports focal hyperpigmentation — including involvement of the face, gingiva and breasts — in about 1% of patients receiving up to eight doses per month, against none on placebo. In a separate study, 38% developed it after eight consecutive daily doses, with a further 14% developing new pigmentary changes over eight more days. Two sentences from that section are rarely repeated: "Patients with dark skin were more likely to develop focal hyperpigmentation," and "Resolution of the focal hyperpigmentation was not confirmed in all patients after discontinuation of VYLEESI." The label advises considering discontinuation if it develops.

Absorption of oral medicines. Bremelanotide slows gastric emptying, which the label says can reduce the rate and extent of absorption of oral medicines taken around the same time. It specifically advises against use with orally administered naltrexone products intended to treat alcohol or opioid dependence, because reduced absorption could cause treatment failure, and advises caution with oral drugs that depend on threshold concentrations to work, such as antibiotics.

What This Article Cannot Tell You

Whether this treatment is appropriate for a particular person depends on facts no article has access to — including whether what they are experiencing meets the definition the label describes, and whether something else explains it.

Low sexual desire has many causes. Medications, thyroid and hormonal conditions, depression, sleep, pain, and relationship circumstances all affect it, and the label explicitly places several of those outside the indication. Distinguishing between them is a clinical assessment. Related reading: Low Libido in Women: Causes, HSDD and Treatment Options and Testosterone for Women and Libido: What the Evidence Says.

A licensed provider can make that assessment. A search result cannot.

Frequently Asked Questions

What is PT-141?

PT-141 is the development name commonly used for bremelanotide, a melanocortin receptor agonist. The FDA-approved bremelanotide product is Vyleesi®, a 1.75 mg subcutaneous injection indicated for premenopausal women with acquired, generalized hypoactive sexual desire disorder, taken as needed at least 45 minutes before anticipated sexual activity.

Is PT-141 the same as Vyleesi?

Not exactly. PT-141 is the development name for the drug substance bremelanotide; Vyleesi® is the FDA-approved 1.75 mg subcutaneous bremelanotide product, with an approved label and indication. Compounded preparations containing bremelanotide or "PT-141" are not Vyleesi and are not FDA-approved drug products. The trial results and safety data on this page come from Vyleesi.

Is compounded PT-141 FDA approved?

No. Compounded preparations are prepared by pharmacies rather than approved as finished drug products, so the FDA has not evaluated them for safety, effectiveness or manufacturing quality. The only FDA-approved bremelanotide product is Vyleesi. Questions about a specific compounded preparation should go to the prescriber and the pharmacy dispensing it.

How does PT-141 work?

Bremelanotide activates melanocortin receptors, most relevantly MC1R and MC4R at therapeutic doses. MC4R receptors are widely present in the central nervous system, which is the basis for the common description of it as acting on the brain. But the label states directly that "the mechanism by which VYLEESI improves HSDD in women is unknown." The clearest established consequence of melanocortin-receptor activity is increased pigmentation, through MC1R on skin melanocytes.

Does PT-141 work?

In the two phase 3 trials of Vyleesi it produced small, statistically significant improvements on a desire questionnaire (+0.30 and +0.42 points on a 1.2–6.0 scale) and a distress questionnaire (−0.37 and −0.29 on a 0–4 scale). The trials did not show a statistically significant increase in the number of satisfying sexual events, a pre-specified secondary endpoint, in either trial. Those results describe Vyleesi at 1.75 mg subcutaneously; no comparable trial data exists for compounded preparations.

Who is PT-141 approved for?

Vyleesi is approved for premenopausal women with acquired, generalized HSDD causing marked distress or interpersonal difficulty, where the low desire is not due to another medical or psychiatric condition, a relationship problem, or another medication. The label states it is not indicated for postmenopausal women or for men, and not indicated to enhance sexual performance.

Is PT-141 approved for men?

No. The Vyleesi label states explicitly that it "is not indicated for the treatment of HSDD in postmenopausal women or in men." There is no FDA-approved bremelanotide product for men, and no approved dose or indication in men.

Is PT-141 "female Viagra"?

No, and the comparison misleads in two directions. Viagra (sildenafil) is a PDE5 inhibitor acting on blood flow to treat erectile dysfunction; Vyleesi is a melanocortin receptor agonist approved for low sexual desire — a different problem with a different mechanism. The nickname also implies an effect on physical performance, which the label rules out: "VYLEESI is not indicated to enhance sexual performance." Comparison: PT-141 vs Viagra: What Each One Is Actually Approved to Do.

How often can you take PT-141?

The Vyleesi label allows no more than one dose in 24 hours and does not recommend more than eight doses per month. In the trials, the median use across 24 weeks was ten injections in total — about two or three a month.

How long does PT-141 last?

The label says this is not known: "The duration of efficacy after each dose is unknown and the optimal window for VYLEESI administration has not been fully characterized." The instruction is to dose at least 45 minutes before anticipated activity.

What if it doesn't work?

The label sets a review point. Section 2.2 instructs prescribers to "discontinue VYLEESI after 8 weeks if the patient does not report an improvement in her symptoms." Whether to stop, continue or reassess the diagnosis is a decision for the prescribing clinician.

Is PT-141 safe?

Vyleesi does not carry an FDA boxed warning, but it is contraindicated in uncontrolled hypertension or known cardiovascular disease and is not recommended for people at high risk of cardiovascular disease. Nausea affected 40% of trial participants, around four in ten discontinued the 24-week trial early, and focal hyperpigmentation is a labelled warning that did not resolve in all patients after stopping. Whether it is appropriate for an individual is a clinical judgement. Compounded preparations have not been evaluated by the FDA at all.

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References

1. VYLEESI (bremelanotide) injection — U.S. Prescribing Information. DailyMed, U.S. National Library of Medicine. Sections 1, 2.1, 2.2, 4, 5.1, 5.2, 6.1, 7.1, 7.2 and 12.1.
2. Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstetrics & Gynecology. 2019;134(5):899–908. PMID 31599840.
3. Thurston L, Hunjan T, Mills EG, et al. Melanocortin 4 receptor agonism enhances sexual brain processing in women with hypoactive sexual desire disorder. Journal of Clinical Investigation. 2022;132(19):e152341. PMID 36189794. ClinicalTrials.gov NCT04179734.
4. Spielmans GI. Re-Analyzing Phase III Bremelanotide Trials for "Hypoactive Sexual Desire Disorder" in Women. Journal of Sex Research. 2021;58(9):1085–1105. PMID 33678061.
5. Kingsberg SA, Clayton AH, Portman D, et al. Failure of a Meta-analysis: A Commentary on Glen Spielmans's "Re-Analyzing Phase III Bremelanotide Trials." Journal of Sex Research. 2021;58(9):1106–1107. PMID 33835907.
6. Spielmans GI, Ellefson EM. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. Journal of Sex Research. 2024;61(4):540–561. PMID 36809187.
7. Parish SJ, Goldstein AT, Goldstein SW, et al. Toward a More Evidence-Based Nosology and Nomenclature for Female Sexual Dysfunctions — Part II. Journal of Sexual Medicine. 2016;13(12):1888–1906. PMID 27843072.

This article is provided for general educational purposes only and is not a substitute for individualized medical advice, diagnosis or treatment. It reports the contents of FDA-approved prescribing information and published trial results, and does not recommend any treatment or dose. The trial and label information here describes Vyleesi®, the FDA-approved bremelanotide product, and does not describe compounded preparations. Low sexual desire has many possible causes and requires clinical assessment. Questions about whether a treatment is appropriate should be discussed with a qualified healthcare professional. AmalfiDuo Journal articles are written by AmalfiDuo Editorial and are not medically reviewed — see our Editorial Policy.

VYLEESI® is a trademark of its respective owner. AmalfiDuo is not affiliated with or endorsed by the owners or manufacturers of this brand.