PT-141 benefits and uses

What the phase 3 trials found

The main evidence comes from two identical 24-week phase 3 trials, RECONNECT studies 301 and 302.¹ They randomized 1,267 premenopausal women with acquired, generalized HSDD to bremelanotide or placebo.¹ Participants had a mean age of 39, and 86% were white and 12% Black.²

In the label's own analysis, desire scores rose 0.5 and 0.6 points with Vyleesi versus 0.2 with placebo.²

What the outcome measures mean

• Desire score: the FSFI desire domain runs from 1.2 to 6, and higher means more desire.² A gain of about 0.3 to 0.4 points over placebo is a small shift on that range.¹²
• Distress score: a single question on distress about low desire over the past 30 days, answered from 0 (never) to 4 (always).² It fell 0.7 points with Vyleesi versus 0.4 with placebo in both studies.²
• Responder threshold: the label counted a desire gain of at least 1.2 points as a response.² The share of women who reached it appears only in label figures.
• Satisfying sexual events: a secondary endpoint. Mean changes were 0.0 versus a drop of 0.1 in study 1 (p = 0.76), and 0.0 versus 0.0 in study 2 (p = 0.70).²
• Global benefit: one question scored from 1 (very much worse) to 7 (very much better), where 5 or more counted as benefit.¹

Limits of the trials

More women on bremelanotide than on placebo left the blinded phase early: 40% versus 13% in study 1, and 39% versus 25% in study 2.² The trial authors list this uneven withdrawal, and a mostly white study group, as limitations.¹ The results apply to premenopausal women only. Effectiveness after menopause has not been established.¹

How independent reviewers read the results

A 2021 re-analysis found that 72.72% of the outcomes listed in the trial protocols were not reported in the main paper.⁹ A 2024 follow-up judged the effects nil to small.¹⁰ It called the benefits statistically modest and limited to outcomes with scant evidence of validity in women with HSDD.¹⁰ The trial investigators published a commentary disputing the 2021 re-analysis.¹¹ Readers weighing the evidence should know both views exist.

Weighing benefit against side effects

In the same trials, about 58% of women on bremelanotide rated themselves as benefiting, against about 36% on placebo.¹ Over the same 24 weeks, 40% had nausea, 20.3% had flushing and 11.3% had headache.² Side effects led 18% to stop, versus 2% on placebo.² Claims that PT-141 works with few side effects do not match these label figures. The label's stopping rule applies when a patient reports no improvement after 8 weeks.²

Earlier and longer studies in women

• Dose-finding trial (12 weeks, 2016): in premenopausal women with sexual dysfunction, the combined 1.25 and 1.75 mg groups gained 0.7 satisfying sexual events a month, versus 0.2 on placebo (p = 0.018).⁸
• Open-label extension (52 weeks): of 684 women who entered, 272 completed it. The authors reported sustained improvement and no new safety signals.⁷

Findings in men

Small placebo-controlled studies from 2004 found erectile responses after injected or nasal doses in healthy men and in men with erectile dysfunction.³⁴ In a 2005 crossover study of 19 men with erectile dysfunction, low-dose nasal PT-141 given with sildenafil produced a greater erectile response than sildenafil alone.¹² A 2008 trial in 342 men who had not responded to sildenafil reported positive results in 33.5% on nasal bremelanotide versus 8.5% on placebo.¹³ The journal attached an expression of concern to it in 2023.¹³ No use in men is FDA approved.² Details are on PT-141 and men's health.

Animal and mechanism findings

In female rats, PT-141 selectively increased solicitation (courtship) behavior without changing lordosis, pacing or other sexual behaviors.¹⁴ Given to rats and nonhuman primates, it caused penile erections, according to a 2003 paper.¹⁵ A 2022 review proposes that it acts on MC4 receptors in the hypothalamus to raise dopamine release, a model built mainly on animal work.¹⁶ The label itself states that the mechanism in women with HSDD is unknown.² Animal results do not show that the same effects occur in people.

What has not been shown

• Benefit after menopause: not established, and the label does not cover postmenopausal women.¹²
• Energy, mood or tanning: the trials did not measure these as benefits, and skin darkening is a labeled side effect, not a goal.²
• Benefit in men: no study in men has led to an approval, and the largest trial in our sources carries an expression of concern.²¹³
• Comparisons: our sources include no head-to-head trial against sildenafil or flibanserin.

More detail: What is PT-141?, PT-141 side effects, PT-141 dosage and PT-141 and women's health.