Topic
Sexual & Reproductive Health
Quick answers
- What is it?
- This hub covers peptides that researchers have studied or that are marketed in connection with sexual desire or arousal: PT-141 (bremelanotide), an FDA-approved medicine, and Melanotan II, an unapproved peptide sold online mainly for tanning but also used off-label for libido or erectile function.
- Why are people interested in it?
- People look into these compounds because of low sexual desire, erectile-function concerns, or because "tanning peptides" sold online are also informally promoted as sexual-enhancement products.
- What has actually been studied?
- Right now this hub has no standalone articles — it consists only of two peptide profile pages, PT-141/bremelanotide and Melanotan II. What's studied differs sharply between them: PT-141 has ten registered human trials including two pivotal Phase 3 studies, while Melanotan II has no completed human efficacy trial for any use.
- How strong is the evidence?
- PT-141, sold as Vyleesi, is FDA-approved (since 2019) specifically for acquired, generalized hypoactive sexual desire disorder in premenopausal women, based on two Phase 3 RECONNECT trials totaling 1,267 participants. Melanotan II is not approved as a medicine anywhere, has never completed a human efficacy trial for tanning or sexual function, and its one registered ClinicalTrials.gov listing is itself described in the source material as a template record, not genuine evidence of active research.
- What don't we know yet?
- For PT-141, it's not established how it performs in men or postmenopausal women, whether its modest average effect is noticeable to most individual women, or its safety beyond about a year of use. For Melanotan II, it's not established whether it does anything for tanning or sexual function at all, since that has never been tested in a controlled trial, and what an unregulated vial sold online actually contains is unverified.
- Where can I read the original research?
- For the full evidence, dosing status, and safety details on each compound, see the individual peptide pages for PT-141 (Bremelanotide) and Melanotan II.
This is the thinnest section of the site, and we say so plainly. PT-141 (bremelanotide) is an FDA-approved medicine with real trial data. Most other claims in this space rest on off-label consumer use with little published human research. We list what has been studied and flag what has not.
Peptides in the Evidence Index
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Frequently asked
What is PT-141 (bremelanotide) approved to treat?
PT-141, marketed under the brand name Vyleesi, has been FDA-approved since 2019 for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women — a persistent, distressing loss of sexual desire not better explained by another medical, relationship, or psychiatric cause. It is not approved for men, for postmenopausal women, or as a general libido enhancer.
Is Melanotan II an approved medicine?
No. Melanotan II has never been approved as a medicine anywhere. It is sold online as an unregulated injectable, marketed mainly for tanning without sun exposure and, informally, as a libido or erectile-function aid — uses no regulator has evaluated it for.
What side effects or harms have been reported for these two peptides?
For PT-141, the pivotal trials reported nausea, flushing, and headache, each occurring in 10% or more of participants, with nausea the most frequent and the main reason some women stopped treatment; a 52-week open-label extension found no new safety signals. For Melanotan II, there is no controlled-trial safety data, but a growing case-report literature (published by dermatologists, urologists, and nephrologists) describes new or darkening moles, a brain-swelling condition called posterior reversible encephalopathy syndrome, acute priapism, kidney (renal) infarction, and gum/cheek pigmentation persisting for months after stopping injections.
Has Melanotan II actually been tested in a clinical trial for tanning or sexual function?
No. No published controlled trial has tested whether Melanotan II works for the uses it's actually sold for — tanning or sexual function. The only trial ever registered for it targets vitiligo (a skin-pigmentation condition), not tanning or sexual function, and the source material's own correction notes that this and seven related ClinicalTrials.gov listings from the same sponsor are template records rather than genuine, verified trials.
Why are 'tanning peptides' associated with sexual effects?
Because PT-141 (bremelanotide) grew out of the same melanocortin-agonist research program that produced the tanning peptide Melanotan II — researchers developing that class of compounds noticed effects on sexual arousal during early testing. That shared origin is likely why peptides marketed for tanning get associated with sexual effects, even though only PT-141 has approved evidence behind that use.
Does this hub cover libido or fertility peptides more broadly?
Not yet. This hub currently contains only these two peptide profiles and no standalone articles, so broader questions about libido peptides in general, fertility, or reproductive health beyond PT-141 and Melanotan II are not covered in the published research we reviewed here.
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Start here for plain-English explanations of clinical trials, evidence levels, and how to read a study.