PT-141 is the development and research name used for bremelanotide, a synthetic cyclic peptide that acts as a melanocortin receptor agonist. Bremelanotide is the active ingredient in Vyleesi, which the U.S. Food and Drug Administration (FDA) approved in 2019 to treat acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women.1 The approved indication applies to low sexual desire that causes marked distress or interpersonal difficulty and is not attributable to a co-existing medical or psychiatric condition, relationship problems, or the effects of a medication or drug substance. Bremelanotide has also been investigated in other population groups, including men and postmenopausal women with sexual dysfunction, although the evidence in these populations is less established than it is in premenopausal women with HSDD.
- What PT-141 is: PT-141 is the development name for bremelanotide, the active ingredient in Vyleesi, the FDA-approved bremelanotide injection.
- FDA-approved use: Vyleesi is approved for acquired, generalized HSDD in premenopausal women when the condition is not attributable to another medical or psychiatric condition, relationship problems, or medication or drug effects.
- What trials found: Phase 3 trials found small but statistically significant improvements in sexual desire and distress related to low desire, but no significant improvement in the number of satisfying sexual events.
- Evidence in men: Studies in men have reported erectile responses, including in men with inadequate responses to sildenafil, but the clinical evidence remains limited and does not support an FDA-approved indication for men.
- Key safety concerns: Labeled risks include nausea, transient increases in blood pressure, decreases in heart rate, and focal hyperpigmentation (localized skin darkening).
- Product differences: Compounded, nasal, and research-market PT-141 products are not the FDA-approved Vyleesi formulation and should not be treated as equivalent to it.
What is PT-141?
PT-141 is the development name for bremelanotide, a synthetic cyclic heptapeptide made up of seven amino acids joined into a ring, and a melanocortin receptor agonist. Bremelanotide is an analogue of alpha-melanocyte-stimulating hormone (α-MSH), a naturally occurring melanocortin peptide that acts on melanocortin receptors. Bremelanotide activates several melanocortin receptor subtypes, with the highest affinity for MC1R and MC4R, according to the FDA's 2019 Vyleesi official prescribing information.1
In a double-blind, placebo-controlled crossover study of men with organic erectile dysfunction, Wessells et al. (2000) found that Melanotan II, a synthetic α-MSH analogue, produced erections and significantly increased sexual desire compared with placebo.2 These observations prompted further investigation of melanocortin receptor agonists for sexual dysfunction, eventually leading to the development of PT-141.
PT-141, bremelanotide, and Vyleesi: what is the difference?
PT-141 is the name used for bremelanotide during its development and research, while bremelanotide is the generic name and active ingredient in Vyleesi, the brand name for the FDA-approved prescription injection. Vyleesi is supplied as a single-dose prefilled autoinjector for subcutaneous use. PT-141 is also used to describe bremelanotide products sold as vials or nasal sprays, which are separate from the FDA-approved Vyleesi product.
What does PT-141 do in the body?
After administration, PT-141 (bremelanotide) binds to melanocortin receptors (MCRs), which are expressed throughout the body, including the brain. Bremelanotide is a nonselective MCR agonist, activating MC1R, MC4R, MC3R, MC5R and MC2R. Receptor activation alters intracellular signaling and, in neurons, can modify neuronal activity.1
MC4R is the receptor subtype most closely associated with bremelanotide's effects on sexual function. Pfaus et al. (2022) identified MC4R as the MCR subtype most relevant to bremelanotide at therapeutic doses and described its predominant expression in the medial preoptic area of the hypothalamus, a region involved in female sexual function.3
The clinical effects of bremelanotide have been demonstrated in premenopausal women with HSDD. Kingsberg et al. (2019) evaluated 1.75 mg of subcutaneous bremelanotide in two Phase 3 trials involving 1,267 women. After 24 weeks, bremelanotide increased sexual desire and reduced distress associated with low sexual desire compared with placebo.4 Bremelanotide has also been investigated in men with erectile dysfunction, although this use remains outside the FDA-approved indication.
Thurston et al. (2022) studied 31 premenopausal women with HSDD in a randomized, placebo-controlled crossover trial. A 1.75-mg subcutaneous dose increased sexual desire for up to 24 hours compared with placebo. During visual erotic stimulation, functional MRI showed changes in activity in the cerebellum, supplementary motor area and secondary somatosensory cortex, with increased functional connectivity between the amygdala and insula.5
The FDA states that the precise mechanism by which Vyleesi improves HSDD remains unknown. Bremelanotide also has peripheral effects, including a transient increase in blood pressure after administration; other adverse effects are addressed in the safety section below.1
What is bremelanotide FDA-approved for?
The FDA approved bremelanotide (Vyleesi) in 2019 for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). HSDD is a persistent lack or reduction in sexual desire that causes significant distress or interpersonal difficulty. In the Vyleesi prescribing information, the FDA specifies that the condition must be characterized by low sexual desire causing marked distress or interpersonal difficulty and not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication or drug substance.1
The FDA's indication is limited to premenopausal women with acquired, generalized HSDD. Vyleesi is not indicated for HSDD in postmenopausal women or men, and it is not indicated to enhance sexual performance.1
What does the research show in women?
The strongest evidence for bremelanotide in women comes from the two Phase 3 RECONNECT trials, which enrolled 1,267 premenopausal women with HSDD. Participants received 1.75 mg of subcutaneous bremelanotide or placebo as needed for 24 weeks. The prespecified outcomes were change in sexual desire, measured with the Female Sexual Function Index (FSFI) desire domain, and distress related to low sexual desire, measured with item 13 of the Female Sexual Distress Scale–Desire/Arousal/Orgasm (FSDS-DAO).4
The placebo-adjusted difference in the FSFI desire score was 0.30 points in one trial and 0.42 points in the other, with an integrated difference of 0.35. The FSFI desire domain ranges from 1.2 to 6, with higher scores indicating greater desire. For distress, the placebo-adjusted differences were 0.37 and 0.29 points, with an integrated difference of 0.33, on a 0-to-4 scale, where higher scores indicate greater distress.4 The number of satisfying sexual events did not differ significantly between bremelanotide and placebo, consistent with the FDA's review of the trial data.1,4
A 52-week open-label extension of the RECONNECT trials, reported by Simon et al. (2019), followed women who continued bremelanotide after the 24-week core phase. Of the 684 women who entered the extension, 272 completed 52 weeks. There was no placebo group, so the efficacy analyses were only descriptive.6 The extension, like the pivotal trials, was funded by Palatin Technologies and AMAG Pharmaceuticals.
In a 2026 systematic review and meta-analysis, Toledo et al. included 36 studies of treatments for female sexual desire, arousal, and orgasmic dysfunction without sexual pain conditions. Meta-analyses found that bremelanotide improved total FSFI scores and the desire and arousal domains. The review also found improvements with flibanserin and mindfulness-based cognitive behavioral therapy, with reductions in sexual distress reported across these interventions.7
The RECONNECT trials enrolled a predominantly White population (85.6%) at largely US-based sites (96.6%), which limits generalizability to more diverse populations.4
What does PT-141 do in men?
In a 2004 study, Rosen et al. evaluated subcutaneous PT-141 in healthy men and in men with erectile dysfunction who had an inadequate response to 100 mg sildenafil (Viagra). PT-141 produced a significant erectile response at 4 and 6 mg in the men with erectile dysfunction, while healthy men also showed significant erectile responses at doses above 1 mg. The responses were measured without visual sexual stimulation in the healthy participants, supporting a centrally mediated effect.8
The research followed observations made with Melanotan II, the compound from which bremelanotide was developed. In men with organic erectile dysfunction, a study found that Melanotan II produced erections and increased sexual desire compared with placebo.2 In a double-blind, placebo-controlled study, Diamond et al. (2004) found that intranasal PT-141 produced a statistically significant erectile response at doses above 7 mg compared with placebo in healthy men and men with mild-to-moderate, Viagra-responsive erectile dysfunction.9
Intranasal bremelanotide was also evaluated by Safarinejad and Hosseini (2008) in 342 men with erectile dysfunction who had not responded to sildenafil. After treatment with 10 mg bremelanotide or placebo, 33.5% of men in the bremelanotide group reported a positive clinical response compared with 8.5% in the placebo group, and intercourse satisfaction was also higher with bremelanotide.10 However, The Journal of Urology later issued an Expression of Concern regarding the study, stating that the article was under further review and that its findings should be interpreted with caution pending additional information from the authors and their institutions.11
These studies are now more than 15 years old, and the male clinical evidence remains small. A 2026 clinical commentary by Boyne and Lipshultz in American Urological Association News reviewed PT-141 among peptide approaches being investigated for male sexual dysfunction.12 The authors described the early male studies as showing erectogenic effects in men who responded to PDE5 inhibitors and in those who did not, while noting that PT-141 remains not an approved treatment option for male sexual dysfunction. The continued clinical discussion of PT-141 suggests that its potential role in male sexual dysfunction remains under consideration, but it has yet to translate into an approved treatment for men.
Is PT-141 better than Viagra?
There is no evidence that PT-141 is better than Viagra because the two drugs work through different mechanisms and are used to address different sexual problems. Viagra (sildenafil) is FDA-approved for erectile dysfunction and works by increasing blood flow to the penis. PT-141 (bremelanotide) acts on melanocortin receptors in the central nervous system and has been studied for its effects on sexual arousal and erections in men, but it is not FDA-approved for erectile dysfunction. As of November 2026, there have been no head-to-head clinical trials showing an advantage of one over the other.
| PT-141 (Vyleesi) | Viagra (sildenafil) | Cialis (tadalafil) | Addyi (flibanserin) | |
|---|---|---|---|---|
| How it works | Acts on melanocortin receptors in the brain | Increases blood flow to the penis (PDE5 inhibitor) | Increases blood flow to the penis (PDE5 inhibitor) | Acts on serotonin receptors involved in sexual desire |
| FDA-approved for | Acquired, generalized HSDD in premenopausal women | Erectile dysfunction | Erectile dysfunction; benign prostatic hyperplasia | Acquired, generalized HSDD in premenopausal women |
| How it is given | Injection under the skin with an autoinjector pen | Oral tablet | Oral tablet | Oral tablet |
| When taken | At least 45 minutes before anticipated sexual activity, as needed | About 1 hour before sexual activity, as needed | Once daily, as needed | Once daily at bedtime |
How is FDA-approved bremelanotide used and how fast does it work?
FDA-approved bremelanotide (Vyleesi) is given as a 1.75-mg subcutaneous injection using a single-dose prefilled autoinjector. It is injected into the abdomen or thigh at least 45 minutes before anticipated sexual activity, as needed. The FDA label specifies no more than one dose in 24 hours and recommends no more than eight doses per month.1
The approved product is an injection, not a nasal spray. Nasal formulations marketed as PT-141 are separate products and are not the FDA-approved Vyleesi formulation.
The FDA label does not specify a fixed duration of effect or an exact time at which the drug begins to work. It states that the optimal timing has not been fully characterized and that the duration of efficacy after each dose is unknown. Patients may determine the timing that works for them based on the duration of effect on sexual desire and adverse effects such as nausea.1 The label also recommends discontinuing Vyleesi after 8 weeks if the patient does not report an improvement in symptoms.
PT-141 side effects and safety
The FDA label for Vyleesi (bremelanotide) identifies transient increases in blood pressure, focal hyperpigmentation and nausea as the principal warnings and precautions associated with treatment. The label also addresses cardiovascular risk, drug interactions and pregnancy.1
Blood pressure and heart rate
Vyleesi temporarily increases blood pressure and reduces heart rate after each dose. In clinical studies, the maximum increases were 6 mmHg in systolic blood pressure and 3 mmHg in diastolic blood pressure, with the blood-pressure increase peaking 2 to 4 hours after dosing. Heart rate decreased by up to 5 beats per minute. Blood pressure and heart rate generally returned to baseline within 12 hours.1
Vyleesi is contraindicated in patients with uncontrolled hypertension or known cardiovascular disease and is not recommended for patients at high risk for cardiovascular disease. The FDA label advises assessment of cardiovascular risk before treatment and periodically during treatment.1
Focal hyperpigmentation
Focal hyperpigmentation, or localized skin darkening, occurred in 1% of patients receiving up to eight Vyleesi doses per month in the Phase 3 placebo-controlled trials. The pigmentation occurred on areas including the face, gums and breasts. In a separate study in which Vyleesi was administered daily for eight days, 38% of patients developed focal hyperpigmentation; among those who continued treatment for another eight consecutive days, a further 14% developed new pigment changes. Patients with darker skin were more likely to develop focal hyperpigmentation. Resolution was not confirmed in all patients after discontinuation.1
The FDA does not recommend more than eight Vyleesi doses per month and advises consideration of discontinuation if hyperpigmentation develops.1
Nausea
Nausea was the most common adverse reaction in the Phase 3 placebo-controlled trials, occurring in 40% of Vyleesi-treated patients. Antiemetic treatment was required by 13%, and 8% discontinued treatment because of nausea. The FDA label states that nausea improves in most patients after the second dose. Persistent or severe nausea may warrant discontinuation, while antiemetic treatment may be considered for patients who wish to continue treatment.1
Drug interactions
Vyleesi can slow gastric emptying and may affect the absorption of oral medicines. It reduces systemic exposure to oral naltrexone, and the FDA advises against using Vyleesi with oral naltrexone-containing products prescribed for alcohol or opioid dependence. The FDA also reports an interaction with indomethacin in its drug-interaction studies.1
Pregnancy
Vyleesi is not indicated during pregnancy. The FDA label advises discontinuing treatment if pregnancy is recognized and recommends effective contraception for women of reproductive potential during treatment.1
Other adverse reactions occurring in more than 4% of Vyleesi-treated patients included flushing, injection-site reactions, headache, and vomiting.1
FDA-approved vs. compounded vs. research-market PT-141
FDA approval means that the FDA has reviewed the evidence submitted for a particular drug product and determined that its known benefits outweigh its risks for its approved conditions of use. Vyleesi is the FDA-approved prescription product containing bremelanotide. Its approval is for acquired, generalized HSDD in premenopausal women and applies to the specific product and indication described in its prescribing information.1
Compounded PT-141 is bremelanotide prepared by a compounding pharmacy for a particular medical purpose under the requirements that apply to compounded drugs. Compounded drugs are not FDA-approved, so the FDA does not review their safety, effectiveness or quality before they are dispensed. A compounded preparation may also differ from Vyleesi in its formulation, amount of active ingredient, route of administration or packaging. Compounding can be lawful when the applicable federal and state requirements are met; the legality of a particular bremelanotide preparation depends on those requirements and the circumstances of the compounding. For the broader compounding framework, see our peptide therapy guide.
Research-market PT-141 refers to bremelanotide products sold online as research or laboratory products, outside the FDA-approved Vyleesi product. On August 24, 2026, the FDA issued warning letters to several online peptide sellers whose websites marketed PT-141 or bremelanotide products. The FDA determined that the claims made about those products established an intended use as drugs for humans and identified them as unapproved new drugs, despite their research-use labeling.13,14
What should you ask a clinician about PT-141?
Questions for a clinician can help someone considering PT-141 understand whether the treatment is appropriate for their situation and what to expect from its use:
- What exact product is being prescribed?
- Is this use FDA-approved or off-label?
- What evidence supports its use for my specific goal?
- Which heart or blood-pressure risks matter for me?
- Which side effects should prompt me to stop treatment or contact you?
- Is the product FDA-approved or compounded, and which pharmacy will dispense it?
A registered dietitian's perspective on PT-141
Before considering PT-141, it is important to note that a shift in sexual desire can occur as a result of changes in general well-being. Changes in hormonal health, the use of certain medications or restrictive eating can also affect energy, which may be a factor in changes in sexual desire.
It is also important to consider existing gastrointestinal conditions because, in the Phase 3 trials, 40% of women receiving Vyleesi experienced nausea, with 13% requiring antiemetic treatment and 8% discontinuing because of nausea.1 So this would be useful context if you and your clinician have already decided that PT-141 is being considered. PT-141 can also slow gastric emptying and significantly reduce systemic exposure to oral naltrexone. If you are taking oral naltrexone for alcohol or opioid dependence, or indomethacin for inflammatory conditions, I advise discussing these with your prescribing clinician to ensure their therapeutic efficacy isn't compromised.
Women researching PT-141 may also encounter libido supplements and peptide-stack marketing. I would want any supplements or peptide products being considered or already used disclosed to the clinician, so their ingredients, intended effects and potential interactions can be assessed alongside prescribed treatment or any underlying issues that may need further evaluation.
Frequently asked questions
Is PT-141 nasal spray safe?
There is no FDA-approved PT-141 nasal spray. The FDA-approved bremelanotide product, Vyleesi, is a subcutaneous injection. Nasal bremelanotide was studied in early clinical trials, including studies in men with erectile dysfunction, but those formulations were not developed into an FDA-approved nasal product. Nasal PT-141 products currently sold as compounded or research-market products have not undergone FDA review as approved medicines for safety, effectiveness, or quality.1,9
How long do PT-141's effects last?
The exact duration of bremelanotide's effect after each dose is unknown. The FDA label states that the duration of efficacy has not been established and that the optimal timing of administration has not been fully characterized.1
Does PT-141 increase testosterone?
There is no established evidence that PT-141 increases testosterone. Bremelanotide acts as a melanocortin receptor agonist and is not a testosterone or other hormone therapy. In the RECONNECT trials, its effects on sexual desire were observed across different baseline bioavailable testosterone levels.4
Does insurance cover PT-141?
Insurance coverage for FDA-approved Vyleesi varies by health plan, so patients should check their individual prescription benefits. Manufacturer assistance may also depend on eligibility and insurance status. Compounded or online PT-141 products are generally not covered as prescription medicines.
Is PT-141 the same as Melanotan II?
No. Melanotan II was initially studied for its effects on skin pigmentation, but researchers also observed effects on sexual function. This led to the development of PT-141 (bremelanotide), a related peptide studied for sexual dysfunction.2 Bremelanotide is the active ingredient in Vyleesi, an FDA-approved treatment for acquired, generalized HSDD in premenopausal women. Melanotan II is not FDA-approved for any medical use.
References
- FDA. Vyleesi Prescribing Information. 2019. Available at: accessdata.fda.gov
- Wessells H, et al. 2000. Available at: pubmed.ncbi.nlm.nih.gov/11018622
- Pfaus JG, et al. 2022. Available at: pubmed.ncbi.nlm.nih.gov/33455598
- Kingsberg SA, et al. 2019. Available at: pubmed.ncbi.nlm.nih.gov/31599840
- Thurston L, et al. 2022. Available at: pubmed.ncbi.nlm.nih.gov/36189794
- Simon JA, et al. 2019. Available at: pubmed.ncbi.nlm.nih.gov/31599847
- Toledo RG, et al. 2026. Available at: pubmed.ncbi.nlm.nih.gov/40543759
- Rosen RC, et al. 2004. Available at: pubmed.ncbi.nlm.nih.gov/14999221
- Diamond LE, et al. 2004. Available at: pubmed.ncbi.nlm.nih.gov/14963471
- Safarinejad MR, Hosseini SY. 2008. Available at: pubmed.ncbi.nlm.nih.gov/18206919
- AUA. Expression of Concern. Available at: auajournals.org
- Boyne AM, Lipshultz LI. AUA News, April 2026. Available at: auanews.net
- FDA warning letter: NuScience Peptides. 2026. Available at: fda.gov
- FDA warning letter: TXP Innovations. 2026. Available at: fda.gov