Priapism, kidney failure, ICU stays, and the melanoma problem nobody can count: melanotan II is the one gray-market peptide with a deep published harm file — because people have been injecting it since the 1990s.
Why this compound’s file is different
Most pages in this section have to say “no human harm record exists.” Melanotan II is the exception. It has been sold online longer than almost any other gray-market peptide, and the case literature shows it: this is what a harm record looks like when a compound has had thirty years to accumulate one. Case reports are single cases — they establish that something can happen, never how often. Printed at that size, melanotan II’s file is still the richest of any cosmetic peptide.
Documented in published case reports
- Priapism requiring emergency treatment — multiple published case reports of ischemic priapism after melanotan II use; in one, erectile function had not recovered at four weeks. Priapism is a time-critical emergency: tissue damage is measured in hours.
- Rhabdomyolysis and renal impairment — a poison-center case report describes sympathomimetic toxicity with muscle breakdown and kidney injury after a single large self-administered amount bought online; the patient’s muscle-damage marker was massively elevated and he spent three days in intensive care.
- Renal infarction — a 2020 case report judged kidney infarction (tissue death from lost blood flow) most likely caused by melanotan II.
- Systemic effects in the early studies — the 1990s pilot literature itself records nausea, flushing, and blood-pressure effects. This compound was never inert; it was abandoned as a drug candidate and adopted as a cosmetic.
Moles, melanoma, and the surveillance problem
The human literature since the pilot studies consists largely of harm reports. One review’s count of the published cases: melanoma (2 cases), melanoma in situ (1), eruptive dysplastic nevi (4), rapid change in existing nevi (5), and a mucosal melanoma after a melanotan nasal product (1).
The newest entry: a September 2026 JAAD Case Reports report — a 46-year-old man whose product came from a gym; multiple moles changed within weeks; biopsy found early-stage melanoma. The authors could not exclude unrelated causes — he had prior skin cancer, a family history, and heavy tanning-bed use — and we print that confounder at full size. FDA’s own compounding-risk page states that published case reports for melanotan II “discuss serious adverse events including melanoma.”
The deeper problem is structural, and it does not depend on whether melanotan II causes melanoma — which is unproven and, without epidemiology, unprovable today. A compound that darkens skin and changes moles degrades the exact visual signal that patients and dermatologists use to catch melanoma early. Eruptive and changing moles after use are documented. A user with many moles is, measurably, making their own cancer surveillance worse while believing they look healthier. That masking effect is the strongest sentence in this compound’s file.
The official record
- The UK’s MHRA received 13 suspected adverse-reaction reports for melanotan II between 2011 and 2021 (Yellow Card system).
- FDA lists melanotan II among compounds that may present significant safety risks in compounding, citing immunogenicity from aggregation and impurities alongside the case reports.
- Gray-market melanotan II was in the falsified-product set of the Belgian public-health lab study (Janvier et al., Talanta, 2018) — the set in which two-thirds of products fell below 95% purity.
Get medical care now if
- An erection lasting more than four hours — this is an emergency, not an embarrassment. Go to an emergency department and say what you took.
- Muscle pain with weakness, dark or cola-colored urine, or sharply reduced urination after use — the rhabdomyolysis pattern; kidneys are the stake.
- Chest pain, severe headache, or fainting.
- Any mole that changes — size, shape, color, border, symptoms — after melanotan use: a dermatologist, promptly, and tell them about the melanotan. The disclosure is what lets them interpret what they see.
If you were harmed, report it to FDA MedWatch — for a compound sold entirely outside the medical system, case reports and adverse-event filings are the only surveillance there is.
The bottom line
Melanotan II is the control case for this entire site: it is what the other compounds’ files will look like in twenty years if their use continues at scale without surveillance — a stack of single cases, each one someone who read that serious outcomes were rare. See also Cancer and Peptides and Contaminated Products & Forged Lab Reports.
Educational information only — not medical or legal advice. Status as of November 9, 2026. See Our Legal Mandate.