Peptides for testosterone, libido and tanning: what the research shows
- 4 compounds
- Evidence level on each
- Last reviewed Nov 5, 2026
What they are
“Sexual health peptides” is an online label for compounds studied for libido, erections, testosterone or tanning. PT-141 and Melanotan 2 act on melanocortin receptors in the brain; Melanotan 1 (afamelanotide) mainly darkens skin; enclomiphene, a pill, raises the hormones that tell the body to make testosterone. Two have an approved drug form, each for one use.
This page covers compounds studied for sex drive, erections, testosterone and tanning. Two have an FDA-approved drug form, each for one narrow use; the other two have none, and one of them isn’t a peptide. Here is what each one is, what it has been studied in, and what the studies found.
The compounds
A pill, not a peptide: one of the two mirror-image forms that make up clomiphene, a fertility drug. It raises LH and FSH, the pituitary hormones that tell the testes to make testosterone.
Studied inHuman
Status: Not FDA-approved. In 2018 the European Medicines Agency refused to approve it (as Encyzix), saying the trials hadn’t looked at whether it improves symptoms and citing a risk of blood clots in veins (EMA, 2018).
In two 16-week trials in overweight men with low testosterone, enclomiphene raised testosterone and kept sperm counts in the normal range; testosterone gel raised testosterone too but sharply reduced sperm production (Kim et al., 2016). A 2025 review of randomized trials of enclomiphene and clomiphene found no difference in testosterone compared with gel (Hohl et al., 2025).
A lab-made peptide based on alpha-MSH, the hormone that darkens skin. It acts on melanocortin receptors in the skin and the brain; PT-141 was derived from it.
Studied inAnimalHuman
Status: Not approved for any use. The FDA lists it among compounding substances with safety concerns, citing case reports of melanoma, a rare brain swelling syndrome (PRES) and priapism (FDA, 2026).
In 10 men with erectile dysfunction from physical causes, erections followed 12 of 19 injections versus 1 of 21 placebo doses, and desire rose; 4 of the 19 injections caused severe nausea (Wessells et al., 2000). A 2017 review linked unregulated use for tanning with changes in existing moles and new moles, plus four case reports of melanoma, while noting there’s no conclusive proof of cause (Habbema et al., 2017).
Melanotan 1 (afamelanotide)
The research name for afamelanotide, a lab-made, longer-lasting version of alpha-MSH, the hormone that darkens skin.
Studied inHuman
Status: FDA-approved as Scenesse, an implant placed under the skin, to increase pain-free light exposure in adults with erythropoietic protoporphyria (EPP), a rare disorder that makes sunlight painful (FDA, 2019). Not approved for tanning.
In people with EPP, implants increased time spent in direct sunlight without pain: a median of 69.4 hours versus 40.8 on placebo in the U.S. trial (Langendonk et al., 2015). The Scenesse label recommends a full-body skin exam twice a year (FDA label, 2024). Melanotan 1 sold online for tanning isn’t Scenesse; the 2017 review above linked unregulated use with mole changes (Habbema et al., 2017).
Full summary in progress.
A lab-made peptide that acts on melanocortin receptors in the brain.
Studied inHuman
Status: FDA-approved (Vyleesi) for low sexual desire in premenopausal women.
Two phase 3 trials of 1,267 women found small, significant gains in desire; nausea, flushing and headache were more common than on placebo (Kingsberg et al., 2019).
Before you compare them
- Enclomiphene isn’t a peptide. It’s a pill, here because it’s so often compared with peptides for testosterone.
- Approved for one use isn’t approved for every use. Bremelanotide (Vyleesi) is approved for low sexual desire in premenopausal women, and afamelanotide (Scenesse) for one rare light-sensitivity disorder. Neither is approved for men’s sexual health or for tanning.
- More testosterone isn’t the same as feeling better. Europe’s medicines agency refused enclomiphene partly because its trials measured hormone levels, not symptoms (EMA, 2018).
- Melanotan 2 carries safety warnings. The FDA lists it among compounding substances with safety concerns (FDA, 2026).
New to reading studies? Our guide to how to read a peptide study explains what cell, animal and human evidence can and can’t tell you.
Questions
Which peptide increases testosterone?
Of the compounds on this page, only enclomiphene has trials showing it raises testosterone, and it’s a pill, not a peptide: in two 16-week trials it raised testosterone while keeping sperm counts normal (Kim et al., 2016). PT-141 and the melanotans were studied for desire, erections and tanning, not testosterone. We’re still reviewing peptides studied for the hormones that control testosterone, such as kisspeptin and gonadorelin.
What’s better, peptides or TRT?
We haven’t found a study comparing any peptide on this page with testosterone replacement therapy (TRT). The closest comparison is enclomiphene, a pill: against testosterone gel, both raised testosterone, but only enclomiphene kept sperm counts normal (Kim et al., 2016). A 2025 review of randomized trials found no difference in testosterone between these pills and gel (Hohl et al., 2025). Europe’s medicines agency still refused enclomiphene, saying the trials hadn’t looked at symptoms (EMA, 2018).
Enclomiphene vs clomiphene: what’s the difference?
Clomiphene is a mix of two mirror-image forms, and enclomiphene is one of them. In 66 men at one academic center who took clomiphene and later switched to enclomiphene, testosterone rose a median 166 ng/dL on enclomiphene versus 98 on clomiphene, a difference that wasn’t statistically significant. Lower libido, low energy and mood changes were reported less often on enclomiphene (Saffati et al., 2024). It was a look back at clinic records, not a randomized trial.
Do peptides help your libido?
Some had small effects in trials. In two phase 3 trials of 1,267 premenopausal women, PT-141 produced small but significant gains in desire (Kingsberg et al., 2019). In 10 men with erectile dysfunction, desire was higher after Melanotan 2 injections than after placebo (Wessells et al., 2000). Only PT-141 is approved, and only for premenopausal women.
Are tanning peptides safe?
Neither Melanotan 1 nor Melanotan 2 is approved for tanning. The FDA lists Melanotan 2 among compounding substances with safety concerns, citing case reports of melanoma, PRES and priapism (FDA, 2026). A 2017 review linked unregulated use of both with mole changes, new moles and four melanoma case reports, while noting there’s no conclusive proof of cause (Habbema et al., 2017). Even for the approved form of Melanotan 1, Scenesse, the label recommends a full-body skin exam twice a year (FDA label, 2024).
What’s the downside of taking these?
Nausea is the most common one in trials: severe after 4 of 19 Melanotan 2 injections (Wessells et al., 2000), and more common on PT-141 than on placebo, along with flushing and headache (Kingsberg et al., 2019). Europe’s review of enclomiphene raised a risk of blood clots in veins (EMA, 2018). For the unapproved ones, too few people have taken them in studies to know the long-term risks.
Sources
- Kim ED, et al. Oral enclomiphene citrate raises testosterone and preserves sperm counts in obese hypogonadal men, unlike topical testosterone: restoration instead of replacement. BJU Int. 2016;117(4):677-85. PubMed 26496621
- Hohl A, et al. Clomiphene or enclomiphene citrate for the treatment of male hypogonadism: a systematic review and meta-analysis of randomized controlled trials. Arch Endocrinol Metab. 2025;69(5). PubMed 41066380
- European Medicines Agency. Encyzix (enclomiphene): refusal of the marketing authorisation. 2018. EMA page
- Wessells H, et al. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology. 2000;56(4):641-6. PubMed 11018622
- Habbema L, et al. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. Int J Dermatol. 2017;56(10):975-80. PubMed 28266027
- U.S. Food and Drug Administration. Safety risks associated with certain bulk drug substances nominated for use in compounding. Content current as of April 22, 2026. FDA page
- Langendonk JG, et al. Afamelanotide for erythropoietic protoporphyria. N Engl J Med. 2015;373(1):48-59. PubMed 26132941
- Scenesse (afamelanotide) implant prescribing information. Clinuvel; NDA 210797; revised August 2024. FDA label
- U.S. Food and Drug Administration. Scenesse approval letter, NDA 210797. October 8, 2019. FDA letter
- Kingsberg SA, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. 2019;134(5):899-908. PubMed 31599840
- Saffati G, et al. Safety and efficacy of enclomiphene and clomiphene for hypogonadal men. Transl Androl Urol. 2024;13(9):1984-90. PubMed 39434750
Last reviewed Nov 5, 2026 by Reed Calder. Nothing here is medical advice; see our medical disclaimer. Found a mistake? Email editors@peptideresearchstudy.com.