PT-141, melanotan, kisspeptin, hCG and oxytocin get suggested for low libido, erections, testosterone, fertility and tanning as if they were interchangeable. Each one works on a different part of the body: brain circuits for desire, the hormone chain from brain to testes or ovaries, blood flow in erectile tissue, or pigment cells in skin.
See where each one actsAmber marks where the molecule binds. Green marks what changes because of it. Kisspeptin starts at the top of the hormone chain and still answers to the body's own brakes; hCG skips straight to the testes or ovaries. The melanocortin drugs never touch hormones at all.
Grade A means an approved drug or several randomized trials. Grade D means animal or cell data only. The squares show each record's key studies: green ones were done in people, brown ones in animals or cells.
A 9-amino-acid pituitary hormone, FDA-approved as Pitocin for labor and postpartum bleeding; nasal sprays remain unproven.
The pregnancy hormone and an LH look-alike; FDA-approved for male hypogonadism and ovulation, and proven useless for weight loss.
A long-acting copy of the skin-darkening hormone alpha-MSH, FDA-approved as the Scenesse implant for a rare light-pain disorder.
A melanocortin receptor agonist, sold as Vyleesi, FDA-approved in 2019 for low sexual desire in premenopausal women.
A 28-amino-acid gut and nerve peptide that relaxes blood vessels and calms inflammation; approved only in an erectile dysfunction injection.
An unapproved ring-shaped alpha-MSH analog that darkens skin and causes erections; tested in a few small 1990s studies, never approved.
Shortest active piece of kisspeptin, the brain hormone that triggers LH and testosterone release; tested only in small human studies.
Every peptide in this group has at least some human data. That is unusual: most peptides sold for healing or longevity stop at rats. Here the weak spots are small sample sizes and short studies, not missing human data.
Pick the situation. You get the usual medical route first, then each peptide that was tested for it, what was measured and how it came out. Moving a hormone level is not the same result as fixing the problem, so those are marked separately.
1,267 premenopausal women with HSDD, 24-week placebo-controlled trials
A real but small rise in desire and drop in distress. Satisfying sexual events did not increase versus placebo. About 4 in 10 had nausea across the program.
SourceNo adequate trial of nasal oxytocin for sexual function
The nasal-spray literature is small and underpowered, and little of a nasal dose reaches the brain.
SourceHormone studies only
Kisspeptin-10 raises LH in some phases of the cycle. Brain-imaging studies on sexual arousal used kisspeptin-54, a different form.
All controlled studies enrolled men
No study has measured anything in women.
Swipe the table sideways to see all six columns.
| Peptide | What it acts on | Best human evidence | US status | WADA | Main route |
|---|---|---|---|---|---|
| Oxytocin | Oxytocin receptor (OXTR) | Huge labor trials; nasal-spray trials small and mostly negative | FDA-approved | Not named on the list | Intravenous infusion (approved) |
| hCG (Human Chorionic Gonadotropin) | LH receptor (LHCGR) on testes and ovaries | Decades of RCTs in IVF; meta-analysis in male hypogonadism | FDA-approved | Prohibited in men at all times (S2) | Intramuscular injection (urinary hCG: Pregnyl, Novarel) |
| Melanotan-1 (afamelanotide) | MC1R on melanocytes | Two RCTs in EPP; tanning data from small volunteer studies | FDA-approved | Not named on the list | Subcutaneous implant (approved) |
| PT-141 (Bremelanotide) | MC4R and MC1R (melanocortin receptors) | Two phase 3 RCTs, 1,267 women: small rise in desire | FDA-approved | Not named on the list | Subcutaneous injection (approved) |
| VIP (Vasoactive Intestinal Peptide) | VPAC1 and VPAC2 receptors | ED trials behind a UK license; COVID trials negative | Approved outside US | Not named on the list | Intracavernous injection (approved, with phentolamine) |
| Melanotan-2 | MC1R, MC3R, MC4R and MC5R (non-selective) | Two 10-man crossover trials and a 3-man pilot, 1996 to 2000 | Research chemical | Covered by S0 (unapproved substances) | Subcutaneous injection (published studies) |
| Kisspeptin-10 | KISS1R on GnRH neurons | Hormone studies in 4 to 15 people; no outcome trials | In clinical trials | Prohibited in men at all times (S2) | Intravenous bolus or infusion (research) |
Want two of these next to each other on every field? Open the compare tool.
These are the claims you will see online that no human study supports yet. Each one is a gap in the research, not a finding that the peptide fails.
No approved drug in this group is labeled for male desire. The male PT-141 data are small, nasal and from 2004 to 2008.
Postmenopausal women were excluded from the approval trials, and the label says it is not for them.
The evidence is a 3-week hormone study and a 26-man chart review. No randomized trial has counted pregnancies.
Testosterone rose during infusions lasting hours. Constant exposure for 5 days switched the LH response off.
Very little of a nasal dose reaches the fluid around the brain, and no adequate trial has measured sexual function.
The longest controlled exposure to melanotan-2 was 2 weeks. Nobody has studied melanoma risk in a cohort.
Approved as Pitocin for labor, given IV or IM in hospital. No nasal spray is FDA-approved.
WADA: Not named on the listApproved as Pregnyl, Novarel and Ovidrel. A biologic since 2020, so it cannot be compounded.
WADA: Prohibited in men at all times (S2)Approved only as the Scenesse implant for erythropoietic protoporphyria. Not approved for tanning.
WADA: Not named on the listApproved as Vyleesi for premenopausal women with HSDD only. Online "PT-141" is a research chemical, not Vyleesi.
WADA: Not named on the listNot FDA-approved. Licensed for erectile dysfunction in the UK and Denmark.
WADA: Not named on the listNever approved anywhere. FDA cited melanoma, priapism and toxicity reports when it listed it as a safety risk in 2023.
WADA: Covered by S0 (unapproved substances)No approval. On FDA Category 2 (safety risks); advisers voted 11 to 0 against compounding it in 2024.
WADA: Prohibited in men at all times (S2)Each peptide page has a table of the doses used in published trials and on approved labels, with a source for every row. Those tables open with a free account.
Create a free accountOne email when a sexual health or fertility peptide trial reads out, a label changes or the FDA acts on a compounding list. Human evidence first, sources linked.