The best peptides for sexual health, judged by evidence, come down to one approved drug: bremelanotide (Vyleesi), the approved form of PT-141, for premenopausal women with distressing low sexual desire.[3][5] Its benefits are modest and nausea is common. Kisspeptin has small brain-imaging trials, oxytocin did no better than placebo for sexual function, and melanotan II is unapproved with serious safety reports.[8][10][12] Standard treatments, such as PDE5 inhibitors for erectile dysfunction, come first.[1]
This guide grades each option by evidence. It is part of our sexual health peptides hub.
Evidence-graded table
| Peptide or drug | Evidence level | What was shown | FDA status | Our profile |
|---|---|---|---|---|
| PDE5 inhibitors (sildenafil, tadalafil; not peptides) | FDA-approved for this use | First-line for erectile dysfunction[1] | Approved for ED | Not applicable |
| Flibanserin (not a peptide) | FDA-approved for this use | Daily pill for HSDD in women[2] | Approved: women under 65 with acquired HSDD | Not applicable |
| Bremelanotide (Vyleesi, PT-141) | FDA-approved for this use | More desire, less distress than placebo in 1,267 women[5] | Approved 2019: premenopausal women with HSDD[4] | PT-141 |
| Bremelanotide in men | Small human studies | 33.5% vs 8.5% response in men failing sildenafil[7] | Not approved for men[3] | PT-141 |
| Kisspeptin | Small human studies | Changed brain responses to sexual cues in women and men[8][9] | Not approved; kisspeptin-10 on FDA safety-risk list[14] | Kisspeptin-10 |
| Oxytocin (nasal) | Human RCTs (negative) | No better than placebo for sexual function[10] | Not approved for this use | Oxytocin |
| Melanotan II | No evidence, marketing only (for libido) | Case reports of melanoma, priapism and other harms[12][13] | Not approved | Melanotan II |
Start with a medical check and standard care
Sexual problems often have treatable causes: medications such as some antidepressants, diabetes, heart disease, low testosterone, menopause, depression, pain or relationship strain. A clinician visit is the first step.
- Erectile dysfunction: the American Urological Association recommends PDE5 inhibitors such as sildenafil and tadalafil as a first-line option, along with addressing heart and metabolic health.[1] Erection problems can be an early sign of heart disease.
- Low desire in women (HSDD): sex therapy and addressing medications or mood come first. Two drugs are approved: flibanserin, a daily pill now labeled for women under 65 with acquired HSDD, which carries a boxed warning about fainting and low blood pressure with alcohol,[2] and bremelanotide.
- Low testosterone in men: testosterone treatment can help desire when levels are truly low; see our guide to peptides for testosterone.
Bremelanotide (PT-141): the approved peptide
Bremelanotide is a melanocortin receptor agonist that acts in the brain rather than on blood flow. FDA approved it as Vyleesi in June 2019.[4]
- Who it is for: premenopausal women with acquired, generalized HSDD not caused by another condition, relationship problems or medication. It is not indicated for postmenopausal women, for men, or to enhance sexual performance.[3]
- Evidence: in two phase 3 trials of 1,267 women, bremelanotide modestly but significantly increased desire scores and reduced distress compared with placebo.[5]
- How it is used: a 1.75 mg self-injection under the skin at least 45 minutes before sex, no more than once in 24 hours and no more than 8 doses a month.[3]
- Side effects: nausea in 40% (vs 1.3% on placebo), flushing in 20% and headache in 11%.[6] It raises blood pressure briefly after each dose, and about 1% developed darkened skin patches, sometimes on the face or gums.[3]
In men, an older trial in those who did not respond to sildenafil found a positive response in 33.5% on bremelanotide versus 8.5% on placebo, with more side effects.[7] It was never approved for erectile dysfunction. Our PT-141 vs Viagra guide compares the two in detail.
Prescription Vyleesi vs “research” PT-141
PT-141 is also sold online as a research chemical, often as a powder to mix and inject or as a nasal spray. These products are not the same as the approved autoinjector. Their content, purity and dose are unverified, and the dosing rules that limit blood pressure effects and skin darkening (one dose per 24 hours, no more than 8 a month) were set for the approved product.[3] People who buy sexual health products online also risk hidden drug ingredients, a problem FDA has documented repeatedly.[15]
Bremelanotide is still being studied for women in other countries; for example, a 193-woman phase 3 bridging trial in premenopausal women with HSDD was completed by a Korean drug company.[16] For postmenopausal women and men, there is no approved use. If you think bremelanotide might suit you, a prescription lets a clinician check your blood pressure and heart risk first.
Kisspeptin: intriguing early research
Kisspeptin is a natural hormone that sits at the top of the reproductive hormone chain. In a crossover trial of 32 women with HSDD, a kisspeptin infusion changed brain activity in response to erotic videos compared with placebo.[8] In 32 men with low sexual desire, it altered sexual brain processing and increased penile rigidity in response to sexual stimuli by up to 56% versus placebo.[9] These were single-session lab studies, not treatment trials. FDA lists kisspeptin-10 among compounding substances that may present significant safety risks.[14]
Oxytocin: the “love hormone” falls short
In a randomized crossover trial in 30 women with sexual dysfunction, nasal oxytocin before sex for eight weeks improved sexual function scores, but placebo did just as well.[10] Oxytocin gel showed mixed results for vaginal atrophy after menopause.[11] See peptides for menopause.
Melanotan II: why it is on this list as a warning
Melanotan II is an unapproved tanning peptide that can cause erections and increased desire, which is why it is sold online as a “libido” peptide. Reviews and case reports link unregulated melanotan use to new and changing moles, melanomas arising from existing moles, and products of uncertain content and dose.[12][13] FDA’s compounding safety page cites published reports of melanoma and posterior reversible encephalopathy syndrome, a serious brain swelling condition.[14] Our melanotan 1 vs melanotan 2 guide covers the risks.
Questions for your clinician
- Could a medication, hormone level or health condition be causing this?
- Am I a candidate for a PDE5 inhibitor, flibanserin or bremelanotide?
- Would sex therapy or couples counseling help?
- What side effects should I watch for, and how will we judge whether treatment is working?
