PT-141 and men's health

What sources report

Research on bremelanotide in men came before its approval for women.²⁷ The studies below are small, several do not state a trial phase, and most used a nasal form.²³ The approved product is an injection, and no nasal form is approved.¹⁷

Animal work behind the studies

A 2003 paper described PT-141 as a synthetic analog of alpha-MSH that acts at melanocortin receptors, including MC3R and MC4R.¹¹ Given to rats and nonhuman primates, it caused penile erections.¹¹ The later FDA label lists MC1R as its most potent target, ahead of MC4R.¹ Palatin Technologies developed it from melanotan II, and a 2006 review said it might improve sexual function in both males and females.¹² Animal results like these do not prove an effect in men.

Injected doses in healthy men and in men with erectile dysfunction

In a 2004 study, healthy men received doses under the skin ranging from 0.3 to 10 mg.² Erectile responses were statistically significant at doses above 1 mg.² Men with erectile dysfunction who had responded poorly to Viagra then received placebo or one of two doses in a crossover design, and both doses beat placebo.² The abstract does not say how many men took part.

Nasal PT-141 (2004 and 2005)

A 2004 placebo-controlled report covered two studies of nasal PT-141, in healthy men and in men with mild to moderate erectile dysfunction.³ Responses were significant at doses above 7 mg, and the first erection came about 30 minutes after dosing.³ A 2005 randomized crossover study enrolled 19 men with erectile dysfunction.⁴ Low-dose nasal PT-141 given with a low dose of sildenafil produced a greater erectile response than sildenafil alone, with no new adverse events.⁴

The 2008 trial under an expression of concern

A 2008 randomized trial gave nasal bremelanotide or placebo to 342 married men, aged 28 to 59, whose erectile dysfunction had not responded to sildenafil.⁵ It reported positive results in 51 men (33.5%) on bremelanotide versus 13 (8.5%) on placebo.⁵ In 2023 the journal attached an expression of concern to the paper, so its findings should be read with caution.⁵ The reason for the concern was not stated in the record our sources reviewed.

What the studies in men measured

The 2004 studies measured erections with a monitoring device after a dose.²³ The 2008 trial asked men to use at least 16 doses at home and scored erectile function and intercourse satisfaction.⁵ The approved use in women is different: its trials measured desire and distress about low desire over 24 weeks.¹ So the evidence in men speaks to erectile response, not to desire, and the only study of repeated use is the one under an expression of concern.

Safety data that include men

Flushing and nausea were the most common side effects in the 2004 nasal studies of men.³ The 2008 trial reported more drug-related side effects with bremelanotide than with placebo.⁵ A phase 1 study gave single 20 mg nasal doses with alcohol to 24 healthy adults, 12 of them men.¹³ It found no significant drug-related drops in blood pressure.¹³ In the label's clinical studies of the approved injection, each dose raised pressure by up to 6 mmHg systolic and 3 mmHg diastolic, with heart rate down by up to 5 beats per minute.¹ The label contraindicates it in uncontrolled high blood pressure or known cardiovascular disease, and it is not recommended at high cardiovascular risk.¹ Patches of darker skin are a labeled side effect, more likely with daily use.¹

Melanotan II, the parent compound

PT-141 was developed as an analog of melanotan II, and the two differ chemically at one end of the molecule.¹²¹⁴¹⁵ FDA's compounding safety page cites published case reports of serious adverse events, including melanoma, for melanotan II.¹⁶ FDA lists it among substances nominated for compounding and later withdrawn.¹⁶ A 2026 review notes that melanotan II is still found in unregulated markets.¹⁷ The two compounds are not interchangeable, and the research above concerns bremelanotide only. Background is in What is Melanotan 2?.

How it differs from sildenafil

Sildenafil (Viagra) treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation, and it does not increase sexual desire.⁶ Bremelanotide acts on melanocortin receptors, and the label says even its mechanism in women with HSDD is unknown.¹ The 2004 injected study tested bremelanotide in men whose response to Viagra had been inadequate, rather than against Viagra itself.² The two have not been compared head to head in any study our sources found.

Where the question stands in 2026

A 2026 viewpoint in the Journal of Clinical Psychopharmacology asks whether bremelanotide should be considered for sexual arousal and desire disorders in men. Its conclusion was not available to us.¹⁰ A 2026 narrative review calls bremelanotide one of the most clinically established peptides in sexual medicine.¹⁷ The same review raises concerns about product quality, dosing variability and poorly characterized side effects for melanotan II and related peptides sold through unregulated markets.¹⁷ Neither publication changes the label, which still excludes men.¹

Limits of the evidence in men

• Participant numbers are missing from two of the 2004 abstracts, and the combination study had 19 men.²³⁴
• Most results come from a nasal form that was never approved.³⁷
• The largest trial in our sources, with 342 men, carries an expression of concern.⁵
• No trial in men has led to an FDA approval.¹
• Our sources do not confirm why nasal development stopped, and no head-to-head trial against sildenafil was found.

What the label says

The Vyleesi label covers only premenopausal women with acquired, generalized HSDD.¹ It states that Vyleesi is not indicated for HSDD in men and is not indicated to enhance sexual performance.¹ No dose for men has been established, and research-labeled 10 mg vials have no FDA-reviewed directions.¹⁹ The label's dose limits were set for premenopausal women, and none have been set for men.¹ On August 24, 2026, FDA warning letters to two online peptide sellers named PT-141 among unapproved new drugs.⁸⁹ FDA said research-use labeling, such as "research use only", did not change that when the sellers' websites showed human use was intended.⁸⁹

For the full compound profile, see What is PT-141?. The doses used in these studies are listed in PT-141 dosage, and the label's side effect data are in PT-141 side effects. Other compounds are covered in Peptides and men's health.