Melanotan II and PT-141 together
Melanotan II and PT-141 come from the same family of synthetic melanocortin agonists. One became an approved drug with a label full of cautions; the other never got past tiny studies. Taking them together does not combine a tanning peptide with a libido peptide so much as double up on the same receptors.
As sold, one vial: Melanotan II 10 mg, PT-141 10 mg. Statuses as of October 3, 2026. Reviewed by the Grey Peptides Editorial Board. Nothing here is a recommendation or a dose, and no seller is named or linked.
Each component at a glance
From our encyclopedia and FDA's July 2026 Pharmacy Compounding Advisory Committee record. Evidence grades follow the rubric on our methodology page.
| Component | Evidence | FDA status | PCAC, July 2026 | WADA 2026 | WADA 2027 | Interactions |
|---|---|---|---|---|---|---|
| Melanotan II | Low | Research Chemical | Not voted on | Prohibited under S0 (not named) | Prohibited under S0 (not named) | Not yet reviewed |
| PT-141 | High | FDA Approved | Not voted on | Not on the List | Not on the List | Fully reviewed |
What one vial contains: the ratio arithmetic
The vial holds 20 mg in total. Whatever volume of water is added and however much is drawn, every draw carries the components in the same proportions. The table expresses each as a share of the vial, as a multiple of the smallest component (Melanotan II), and as a concentration if the whole vial were dissolved in 2 mL or 3 mL of water. These are arithmetic illustrations of what is in the vial, not suggested volumes or doses.
| Component | In the vial | Share | × Melanotan II | In 2 mL | In 3 mL |
|---|---|---|---|---|---|
| Melanotan II | 10 mg | 50.0% | 1 | 5 mg/mL | 3.33 mg/mL |
| PT-141 | 10 mg | 50.0% | 1 | 5 mg/mL | 3.33 mg/mL |
The Blend & Stack Calculator runs the same arithmetic for any volume and draw, with this composition as a preset (Melanotan II and PT-141, 20 mg (10/10), example composition).
Melanotan II on its own
Melanotan II is an unselective synthetic agonist of melanocortin receptors, the family that controls skin pigment, appetite and sexual function1. Its human evidence is tiny. In three healthy men given injections on alternate days for two weeks, two developed increased pigmentation (human study, three people)2. Crossover studies in 20 men with erectile dysfunction reported erections without sexual stimulation in 17 of 20, with nausea and yawning common (small human studies)3. It is not approved anywhere4.
Its safety record comes mostly from people using it outside trials. A 2020 case report attributed a kidney infarction to it and reviewed earlier reports of rhabdomyolysis and kidney failure, without establishing a mechanism (case reports)5; forum posts from 205 users described tanning before holidays and competitions, often with sunbeds, and the authors flagged pigmented skin lesions, injection infections and contaminated products as risks (qualitative study)6. Vials sold online as 10 mg contained 4.32 to 8.84 mg, some with unknown impurities (laboratory analysis)7.
PT-141 on its own
PT-141 is bremelanotide, approved by FDA as Vyleesi for premenopausal women with acquired, generalised hypoactive sexual desire disorder; the label excludes postmenopausal women, men and use to enhance performance8. In two trials of 1,267 women it improved desire and reduced distress by small amounts over placebo (randomised trials)9. Its label warns of transient blood pressure rises, focal hyperpigmentation in 1% of women using up to eight doses a month, and nausea in 40%8. Our PT-141 guide covers the trials in detail.
Why combining them doubles up
The two are related: both are synthetic melanocortin agonists derived from the α-MSH family, and both act on several of the same receptors101. The idea behind the stack is usually 'a tan from one, libido from the other', but each already does some of both. Melanotan II alone produced sexual effects in its small studies3, and PT-141 alone darkens skin in some users, which is why its label caps monthly use8. Adding them together stacks the shared effects, including nausea, blood pressure changes and pigmentation, without any study of how much. We found no study of the pair in people or animals.
What the ratio means
With 10 mg of each in our example, as the table above shows, each milligram of one comes with a milligram of the other. Their potencies and durations differ, so equal milligrams are not equal effects, and a combined injection makes it impossible to tell which peptide caused a reaction. Our Blend Calculator shows the arithmetic for any composition; it describes content, not a dose.
Interactions and cautions
The Vyleesi label advises against use in people at high cardiovascular risk or with uncontrolled high blood pressure, notes that it may slow stomach emptying and reduce absorption of some oral medicines, and says it should be avoided with oral naltrexone8. In 397 women, ambulatory monitoring after two doses found small blood pressure rises (randomised trial)11. Melanotan II's interactions have not been formally reviewed in our matrix4. Anyone with kidney disease should note the case reports above.
Regulatory status in the United States
PT-141 is approved only as Vyleesi, prescribed for its labelled use. Melanotan II is not approved for any use. A research vial of either, or of both, is not the approved product48.
For tested athletes
PT-141 is not on the WADA Prohibited List; melanotan II, as an unapproved substance, falls under S0 by inference in our tracker4.
What to check before anything else
For low desire in a premenopausal woman who fits the label, the approved product exists and a doctor can prescribe it. For tanning, melanotan II has no approval and a record of serious case reports, and sun protection remains the safer path. Ask whether a certificate of analysis names and quantifies each peptide separately, and remember that online melanotan II vials have been found under-filled and impure7.
Sources
- Tomassi, S., et al. (2022). CLIPSing Melanotan-II to Discover Multiple Functionally Selective hMCR Agonists. J Med Chem, 65. PubMed 35188390 ↗
- Dorr, R. T., et al. (1996). Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci, 58. PubMed 8637402 ↗
- Wessells, H., et al. (2000). Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. Int J Impot Res, 12 Suppl 4. PubMed 11035391 ↗
- Grey Peptides encyclopedia entries for melanotan II and PT-141 (FDA status, WADA status, interaction coverage). Read October 3, 2026.
- Peters, B., et al. (2020). Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep, 9. PubMed 31953620 ↗
- Gilhooley, E., et al. (2021). Melanotan II User Experience: A Qualitative Study of Online Discussion Forums. Dermatology, 237. PubMed 34464955 ↗
- Breindahl, T., et al. (2015). Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug Test Anal, 7. PubMed 24771717 ↗
- VYLEESI (bremelanotide injection) US prescribing information: Indications and Usage with Limitations of Use, Warnings and Precautions 5.1-5.3, Drug Interactions 7.1-7.2. DailyMed version 1, effective November 13, 2025; read October 1, 2026.
- Kingsberg, S. A., et al. (2019). Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol, 134. PubMed 31599840 ↗
- Dhillon, S., et al. (2019). Bremelanotide: First Approval. Drugs, 79. PubMed 31429064 ↗
- White, W. B., et al. (2017). Usefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotide. J Hypertens, 35. PubMed 27977473 ↗
Related: the blends and stacks hub, the Name Decoder, the COA Decoder and the Interaction Matrix. Last updated October 3, 2026.