Melanotan II

What it is

Melanotan II (MT-II) is a synthetic cyclic peptide built from alpha-melanocyte-stimulating hormone (alpha-MSH). It activates several melanocortin receptors in the body rather than just one, which is why it produces two very different effects: it stimulates skin pigment cells to make more melanin (tanning), and, discovered somewhat by accident during early human testing, it also triggers spontaneous erections and increased sexual desire. A small 1996 phase-I study first showed dose-dependent tanning and documented nausea, fatigue, and unprompted erections as side effects. Later placebo-controlled studies specifically tested it as a treatment for erectile dysfunction, with meaningful erection and desire responses but frequent nausea. Despite this research history, melanotan II has never been approved by the FDA or any other medicines regulator for any use; it is sold online as an unregulated 'research chemical' or gray-market 'tan jab,' typically self-injected after reconstituting powder with bacteriostatic water. That unregulated status matters clinically: published case reports describe new or changing moles, dysplastic nevi, and melanoma appearing after melanotan II use, plus at least one case of severe rhabdomyolysis after a high-dose self-injection. Its FDA-approved chemical relative, bremelanotide (PT-141/Vyleesi), uses a related mechanism but is a distinct, regulated product with its own dosing and safety data.

Dose ranges

Study-backed ranges carry a source you can open. Community ranges are widely reported but not clinically established - treat them as what people do, not as advice.

Reconstitution & storage

Melanotan II is sold by research-chemical and peptide vendors as a lyophilized powder that must be reconstituted with bacteriostatic water before subcutaneous injection; no such product is FDA-approved or pharmacopeially standardized. Community and vendor sources commonly describe 5 mg or 10 mg vials mixed with about 1 to 3 mL of bacteriostatic water, with a 10 mg vial plus 2 mL water (yielding roughly 5 mg/mL, or 5,000 mcg/mL) cited most often. These figures are vendor and community practice, not manufacturer specifications, and the purity, sterility, and actual labeled content of such vials cannot be independently verified. [community]

Common stacks

Interactions & cautions

No formal drug-drug interaction studies for melanotan II were located in the peer-reviewed literature; because it is not an approved drug, no regulator-reviewed label or interaction data exists. As a non-selective melanocortin receptor agonist, its published human studies describe centrally mediated effects (spontaneous penile erection, increased sexual desire, nausea, yawning/stretching, facial flushing, fatigue) that are mechanistically related to those of its FDA-approved relative bremelanotide (PT-141/Vyleesi), but no controlled study has evaluated melanotan II's effect on blood pressure, heart rate, or interaction with other medications the way the Vyleesi label does for bremelanotide, so that cannot be extrapolated as established fact. Case reports describe systemic sympathomimetic toxicity (tachycardia, hypertension, mydriasis, tremor) and rhabdomyolysis after high-dose self-injection of unregulated product, which raises theoretical concern about combining melanotan II with stimulants or other sympathomimetic substances, though no formal interaction study confirms this. [study, except where marked community]

Questions people ask

Sources

1. [1]Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study PMID 8637402studyDesign and results of the first human phase-I trial of MT-II: subcutaneous dose escalation from 0.01 to 0.03 mg/kg on alternating days over 2 weeks, dose-dependent skin pigmentation, spontaneous penile erections correlated with a yawning/stretching complex, and side effects of mild nausea and fatigue; recommended 0.025 mg/kg/day for further study. Dorr RT et al., Life Sciences 1996;58(20):1777-1784, doi 10.1016/0024-3205(96)00160-9.
2. [2]Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study PMID 9679884studyDouble-blind, placebo-controlled crossover trial (10 men) at 0.025 mg/kg subcutaneous MT-II: 8 of 10 men achieved clinically apparent erections (mean RigiScan tip rigidity >80% duration 38.0 min vs. 3.0 min placebo, p=0.0045), with nausea, stretching, yawning, and decreased appetite as more frequent side effects than placebo. Wessells H et al., J Urol 1998;160(2):389-393, doi 10.1016/s0022-5347(01)62903-3.
3. [3]Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II PMID 11035391studyReview of the authors' clinical experience with MT-II (0.025 mg/kg subcutaneous) in 20 men with psychogenic and organic erectile dysfunction: erection in 17 of 20 men without sexual stimulation, mean 41 min RigiScan tip rigidity >80%, increased sexual desire after 68% of MT-II doses vs. 19% of placebo doses (P<0.01), and nausea/yawning as the most frequent side effects (severe nausea in 12.9% of subjects at 0.025 mg/kg). Wessells H et al., Int J Impot Res 2000;12(Suppl 4):S74-S79, doi 10.1038/sj.ijir.3900582.
4. [4]Melanotan II injection resulting in systemic toxicity and rhabdomyolysis PMID 23121206studyCase report: a 39-year-old man self-injected 6 mg of unregulated melanotan II (about six times a typical starting dose) and developed tachycardia, hypertension, mydriasis, and tremor, with CPK rising from 1,760 to a peak of 17,773 IU/L (rhabdomyolysis) and myoglobinuria; he improved over 3 ICU days with IV fluids, sodium bicarbonate, and benzodiazepines; product identity was confirmed as melanotan II by mass spectrometry. Nelson ME, Bryant SM, Aks SE, Clin Toxicol (Phila) 2012;50(10):1169-1173, doi 10.3109/15563650.2012.740637.
5. [5]Melanoma associated with the use of melanotan-II PMID 24355990studyCase report of a 20-year-old woman (Fitzpatrick skin type II) diagnosed with melanoma on the gluteal region 3 months after a 3-4 week self-injection course of melanotan II undertaken to augment sunbed tanning; authors caution that melanotan II is unlicensed and incompletely tested, with unknown adverse-effect potential, and recommend counseling at-risk patients. Hjuler KF, Lorentzen HF, Dermatology 2014;228(1):34-36, doi 10.1159/000356389.
6. [6]Eruptive dysplastic nevi following melanotan use PMID 22425244studyCase report of a 25-year-old man (skin phototype II, regular tanning-bed user) who developed a sudden eruption of over 100 melanocytic nevi on his back plus transformation of existing lesions after 4 weeks of subcutaneous melanotan II; histopathology of the 10 most atypical lesions showed dysplastic nevi with severe dysplasia in 3, plus an incidental pigmented basal cell carcinoma; authors advise clinicians to suspect melanotan use when seeing sudden nevus eruption/transformation with disproportionate tanning. Hueso-Gabriel L et al., Actas Dermosifiliogr 2012;103(4):329-331, doi 10.1016/j.ad.2011.10.001.
7. [7]Change in moles linked to use of unlicensed 'sun tan jab' PMID 19174439studyEarly published report (BMJ) documenting transformation of pre-existing melanocytic nevi in patients following use of unlicensed melanotan injections, indexed under pigmented nevus pathology and adverse effects of melanotan-II; full abstract text was not retrievable, so only the report's existence, title, and indexed subject matter are cited here. Langan EA et al., BMJ 2009;338:b277, doi 10.1136/bmj.b277.
8. [8]Melanotan II - DermNet NZreferenceClinical dermatology reference summary: mechanism (non-selective melanocortin peptide mimetic stimulating eumelanin production), unlicensed/untested regulatory status, subcutaneous every-other-day administration pattern, short-term adverse effects (facial flushing, nausea/vomiting, appetite suppression, priapism/spontaneous erections), and long-term concerns (melanoma risk, darkening/new/atypical moles, melanonychia, rhabdomyolysis, encephalopathy, contamination risk from unregulated vials).
9. [9]Tanning, fake tan and MelanotanreferencePublic-health charity summary confirming melanotan II is an artificial melanin-stimulating substance sold as injections/nasal sprays, that it is illegal to sell or supply melanotan injections in the UK, that products are unlicensed and have not been tested for safety, quality, or effectiveness, and may contain undisclosed harmful chemicals.
10. [10]melanotan-II, CID 92432 - PubChem Compound Summary (properties)referenceChemical identity of melanotan II: molecular formula C50H69N15O9, molecular weight 1024.2 g/mol, IUPAC name and canonical SMILES, confirming it as a cyclic (lactam-bridged) heptapeptide.
11. [11]Melanotan-2 Reconstitution: 10mg + 2mL Chart (The Peptide Catalog)communityCommunity-reported reconstitution practice: 10 mg vial plus 2 mL bacteriostatic water yields about 5,000 mcg/mL; a 250 mcg dose equals 0.05 mL (5 units on a U-100 insulin syringe); reconstituted solution should be refrigerated (2-8 C) and used within about 28 days.
12. [12]Melanotan II Dosage, Half-Life & Protocol Guide (Milligram)communityCommunity-reported half-life estimate of approximately 1 hour following subcutaneous injection; community dosing protocols (100-500 mcg/day, 2-3 times weekly, over 8-16 weeks); nausea as the most frequently reported side effect, typically appearing within minutes and lasting 1-2 hours; reconstituted-solution refrigerated storage and 2-4 week use window.