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Research peptide — not a dietary supplement
Melanotan-2 is a research compound, not a regulated dietary supplement. It is typically administered by injection and sold “for research use only.” The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Most Melanotan-2 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 1996–2026 with a typical study size of 1 participants.
Based on 12 studies · 2 RCTs · 28 total participants
Confidence
LowBy outcome
The current evidence for Melanotan-2 is insufficient to assign an evidence score, based on 12 indexed studies. An unapproved, grey-market injectable melanocortin peptide sold illegally online as a 'tanning' agent (and for erections). Honest framing first: melanotan-2 is NOT an approved medicine anywhere — it is an unlicensed, unregulated research chemical with no quality control. Its documented harms are serious: new and changing moles, case reports of MELANOMA, rhabdomyolysis, priapism, nausea/flushing, renal infarction, and posterior reversible encephalopathy. It does NOT replace sun protection and may mask or accelerate skin cancer. Do not confuse it with bremelanotide (PT-141 / Vyleesi), the FDA-approved melanocortin relative — they are different compounds, and melanotan-2 has nothing comparable to bremelanotide's phase-3 evidence. Representative study: PMID 41890775.
The commonly studied dose of Melanotan-2 is No legitimate or recommended dose — melanotan-2 is an unapproved, illegal grey-market injectable with no quality control. We do NOT provide a dosing protocol. Grey-market vials are typically self-injected subcutaneously, but contents are unregulated and harms are documented.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
PT-141
Mostly mechanism / observationalA melanocortin-receptor (MC4R) agonist peptide for low sexual desire. Important honest framing: unlike most 'research peptides', bremelanotide is an FDA-APPROVED prescription drug — Vyleesi, approved 2019 — for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, self-injected subcutaneously on-demand. It has real phase-3 RCTs (the RECONNECT program). The catch: the approved-trial benefit was statistically significant but small (a fraction of a point on desire scales), nausea is very common, and it transiently raises blood pressure. Grey-market 'PT-141' vials sold online are NOT the approved drug and are unregulated.
Last reviewed June 2026 · evidence from 12 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Melanotan-2 (Melanotan II)
An unapproved, grey-market injectable melanocortin peptide sold illegally online as a 'tanning' agent (and for erections). Honest framing first: melanotan-2 is NOT an approved medicine anywhere — it is an unlicensed, unregulated research chemical with no quality control. Its documented harms are serious: new and changing moles, case reports of MELANOMA, rhabdomyolysis, priapism, nausea/flushing, renal infarction, and posterior reversible encephalopathy. It does NOT replace sun protection and may mask or accelerate skin cancer. Do not confuse it with bremelanotide (PT-141 / Vyleesi), the FDA-approved melanocortin relative — they are different compounds, and melanotan-2 has nothing comparable to bremelanotide's phase-3 evidence.
Very low score reflects an unapproved grey-market peptide whose efficacy rests only on tiny decades-old pilot/crossover studies, while the dominant literature is case reports of serious harms including melanoma, rhabdomyolysis, and priapism.
Melanotan-2 (melanotan II, MT-II) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone (alpha-MSH) and a potent, non-selective agonist of the melanocortin receptors (MC1R, MC3R, MC4R, MC5R).
It was originally developed in the 1990s at the University of Arizona as an investigational 'sunless tanning' agent — the idea being that stimulating MC1R on melanocytes drives eumelanin synthesis (tanning) and so might reduce UV exposure and skin-cancer risk.
Early human work was small: a phase-I pilot in 3 male volunteers (Dorr 1996) showed it produced facial/body pigmentation after just five low subcutaneous doses, and a series of double-blind crossover studies in men with erectile dysfunction (Wessells 1998/2000) found it initiated spontaneous erections and increased sexual desire — an off-target consequence of central MC4R agonism.
Crucially, melanotan-2 itself was never approved as a drug; only the structurally related, separately-developed bremelanotide (PT-141, Vyleesi) reached FDA approval, and only for hypoactive sexual desire disorder.
Despite that, melanotan-2 is widely sold online as a grey-market injectable for cosmetic tanning (and bodybuilding-scene use), bypassing all regulatory oversight. This is where the honest read turns sharply negative.
First, the product is unregulated: analyses of vials bought online found under-dosing and unknown impurities, and melanotan-2 is a recurrent target of peptide-drug falsification — buyers have no guarantee of identity, purity, or sterility.
Second, the harm literature is genuinely worrying and dominated by case reports rather than trials: eruptive and changing melanocytic nevi (new/darkening moles), multiple published case reports of cutaneous MELANOMA temporally associated with melanotan-2 use (often alongside sunbed tanning), priapism (prolonged painful erection, a urological emergency), systemic sympathomimetic toxicity with rhabdomyolysis and acute kidney injury, renal infarction, and posterior reversible encephalopathy syndrome (PRES).
Because melanocyte stimulation darkens skin and can cause existing moles to change, melanotan-2 may also mask or delay recognition of an evolving melanoma. It does not provide reliable photoprotection and is not a substitute for sun protection.
Given the absence of any approved indication, the unregulated supply chain, and a real and serious adverse-event literature, the honest evidence and safety verdict is strongly cautionary: this entry exists to inform, not to recommend, and the compound is sandboxed out of all goal- and stack-based recommendations.
Melanotan-2 is an alpha-MSH analogue that activates the melanocortin-1 receptor (MC1R) on melanocytes, stimulating eumelanin synthesis and skin darkening. This is the mechanism behind its grey-market use as a 'tanning' injection — but melanocyte stimulation can also cause existing moles to enlarge/darken and new nevi to erupt, which is central to its skin-cancer safety concern.
As a non-selective melanocortin agonist, melanotan-2 also activates MC4R (and MC3R) in the hypothalamus, where melanocortin signaling modulates central sexual arousal. This is why early ED studies and many grey-market users report spontaneous erections and increased desire — and why priapism is a documented harm.
Because it hits all melanocortin receptors with no selectivity, melanotan-2 drives effects far beyond tanning: sympathomimetic toxicity, blood-pressure/vascular effects, nausea/flushing, and — in case reports — rhabdomyolysis, renal infarction, and posterior reversible encephalopathy. Combined with an unregulated supply chain, these off-target actions define the compound's risk profile.
How Melanotan-2 works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Tap node to isolate • Pinch to zoom • Tap edge for research
No legitimate or recommended dose — melanotan-2 is an unapproved, illegal grey-market injectable with no quality control. We do NOT provide a dosing protocol. Grey-market vials are typically self-injected subcutaneously, but contents are unregulated and harms are documented.
Can be taken without food
| Form | Type |
|---|---|
| 💊None — unapproved grey-market injectable | Recommended |
There is no legitimate pharmaceutical form. Do not confuse melanotan-2 with bremelanotide (PT-141 / Vyleesi), a separate, FDA-approved melanocortin drug. The only evidence-supported way to darken skin safely remains sunless self-tanning lotions (DHA); melanotan-2 provides no reliable photoprotection.
Minimum: 1 weeks
Optimal: 1 weeks
Cycling: Not required
Note: No approved or validated timing. Melanotan-2 is an unapproved, illegal injectable; this library does not endorse or schedule its use.
Dose-response data unavailable. The current published research for Melanotan-2 does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Stimulates eumelanin synthesis and darkens skin — the reason it is bought online. Demonstrated in a tiny early human pilot; in practice it also causes diffuse, sometimes patchy hyperpigmentation and new/darkening moles.
Central MC4R agonism produces spontaneous erections and increased sexual desire — seen in small early ED crossover studies and reported by users. This is also the basis of the priapism risk.
Nausea, facial flushing and a stretching/yawning complex are very common after dosing; severe nausea occurred in a meaningful fraction of subjects in the early human studies.
Eruptive and changing melanocytic nevi are reported, and several case reports describe cutaneous melanoma temporally associated with melanotan-2 use. Pigment darkening can also mask an evolving melanoma. This is the most serious documented concern.
Published case reports include priapism (urological emergency), rhabdomyolysis with acute kidney injury, renal infarction, and posterior reversible encephalopathy syndrome (PRES). These are uncommon but severe.
Avoid entirely — melanocyte stimulation and case-report melanoma associations make this group especially high-risk.
Avoid — sympathomimetic and vascular adverse events (including renal infarction and PRES) are documented.
Avoid — priapism is a documented emergency; the approved option for relevant indications is a prescribed, regulated drug under medical care, not grey-market melanotan-2.
Contraindicated — not studied; avoid entirely.
Melanotan-2 has produced a sympathomimetic toxidrome (tachycardia, hypertension, agitation) with rhabdomyolysis; combining with stimulants could compound cardiovascular and muscle toxicity.
Central pro-erectile melanocortin activity plus a PDE5 inhibitor could increase the risk of priapism, a documented urological emergency with melanotan-2.
Tip: Common in the early human studies; severe nausea occurred in a meaningful fraction of subjects. No safe-use protocol is endorsed.
Tip: Have any new or changing pigmented lesion assessed by a dermatologist; pigment change can mask an evolving melanoma.
Tip: Several published case reports of melanoma associated with use. Seek urgent dermatological review for any suspicious lesion.
Tip: Urological emergency — seek immediate care; documented in case reports, sometimes with lasting erectile dysfunction.
Timing is flexible for Melanotan-2 — consistent daily use matters more than the time of day. There is no approved or validated dosing schedule.
Melanotan-2 should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are nausea and flushing, new, darkening, or changing moles (melanocytic nevi), cutaneous melanoma (case reports). Use caution if any of these apply to you: Not an approved medicine — unlicensed, illegal grey-market injectable; do not self-source; Personal or family history of melanoma, dysplastic nevi, or many moles; Pregnancy and breastfeeding.
Gonadorelin
Mostly mechanism / observationalA synthetic copy of gonadotropin-releasing hormone (GnRH), the hypothalamic decapeptide that drives the pituitary to release LH and FSH. Honest appraisal: it has genuine, trial-backed roles as a diagnostic agent (the GnRH/gonadorelin stimulation test) and — delivered in pulses by an infusion pump — for inducing ovulation in hypothalamic amenorrhea and spermatogenesis in men with congenital hypogonadotropic hypogonadism. Its now-trendy use in men's TRT clinics (compounded, to 'maintain testosterone/fertility' alongside testosterone, often replacing hCG) is largely off-label and has NOT been validated in controlled trials for that purpose.
Melanocortin agonism can affect blood pressure and vascular tone; unpredictable interactions in people on cardiovascular therapy.
Tip: Reported after overdose/use with sympathomimetic toxicity; requires emergency treatment.
Tip: Reported in a case report; possible thrombotic/toxic mechanism. Emergency condition.
Tip: A serious neurological syndrome reported in association with melanotan use; seek emergency care for severe headache, visual change, seizures or confusion.
Tip: Unsterile/contaminated products and shared injecting carry infection risk; identity and purity are not guaranteed.