Melanotan II: The Human Dose Base Is Three Men, and the Injuries Are Published
Four trials, forty-three men, all finished by 2000. Almost everything published in people since is a case report of something going wrong, which makes this the rare compound here with a safety file rather than an empty one.
What it is
Melanotan II is a synthetic cyclic lactam heptapeptide analogue of alpha-melanocyte stimulating hormone, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, formula C50H69N15O9, molecular weight 1024.2. Seven amino acids closed into a ring. It is a non-selective melanocortin receptor agonist (PMID 31953620), so it does not act on the pigment receptor alone, and its reported human effects span pigmentation, spontaneous penile erection and sexual stimulation rather than pigmentation by itself.
Melanotan-1 is a different compound, and the co-inventors say so: melanotan I was tested clinically for tanning of the skin, melanotan II for male erectile dysfunction (PMID 16412534).
What the trials found
Subcutaneous, the word in every one of these papers, means into the fat just under the skin rather than into a vein or a muscle.
Dorr and colleagues, Life Sciences 1996, gave melanotan II to three normal male volunteers by subcutaneous injection, single-blind, alternating-day and placebo-controlled, with melanotan II or saline running Monday to Friday for two weeks on alternate days, so each man received five active doses in total (PMID 8637402). Dosing opened at 0.01 mg/kg and climbed in 0.005 mg/kg increments to 0.03 mg/kg in two of them and 0.025 mg/kg in the third, and a week after dosing ended two of the three showed increased pigmentation in the face, upper body and buttock.
Three men. Five active injections each. That is the whole published human record for melanotan II and skin colour that I could find.
The 1996 paper's conclusion is the sentence the grey market rests on: "The recommended single MT-II dose for future Phase I studies is 0.025 mg/kg/day", subcutaneously, about 1.75 mg for a 70 kg adult, and the dose used in all three later human trials.
It is advice on how to dose the next study, written by the people who had just finished the first one, and it became the number a retail market runs on.
What the erection trials measured
Double blind means neither the men nor the people running the study knew who had the drug and who had the salt water on a given day, and a crossover means each man took both turns.
Ten men with psychogenic erectile dysfunction got 0.025 mg/kg subcutaneously in a double-blind placebo-controlled crossover, erections developed in eight of them, and mean duration of tip rigidity greater than 80 percent ran 38.0 minutes against 3.0 minutes on placebo (PMID 9679884). The same dose in ten men with organic erectile dysfunction risk factors gave erections after 12 of 19 injections against 1 of 21 placebo doses, and severe nausea after 4 of those 19 (PMID 11018622). A randomized crossover in twenty men produced erection in 17 of 20 without sexual stimulation, desire up after 68 percent of doses against 19 percent of placebo doses, severe nausea in about 13 percent (PMID 11035391).
Now go to PubMed, search melanotan II, and filter to the clinical trial publication type. Four records, published between 1996 and 2000 by one University of Arizona group, 43 male subjects in total, and no melanotan II clinical trial I could find in the twenty-six years since.
The registry record that calls itself an example
ClinicalTrials.gov carries NCT07437560, a Phase 2 record listing melanotan II as an adjunct to NB-UVB phototherapy for repigmentation in stable nonsegmental vitiligo, sponsored by Hudson Biotech at Peking University Shenzhen Hospital, 60 participants, first posted 27 February 2026, still marked recruiting. It declares itself fictional in its opening words, summary and detailed description alike beginning "This example interventional study record describes a randomized Phase 2 clinical trial".
Morgan McSweeney, PhD, documented it on 31 July 2026 as one of eight fabricated registrations under that sponsor, all at the same Shenzhen hospital (Dr Noc). I ran the same sponsor query and got the same eight, 3,399 participants between them, two carrying Eli Lilly trial and compound names under a sponsor that is not Lilly. Searching by intervention and by term returned only that record, so I found no genuine registered melanotan II trial there.
How it compares
| Approved? | Human trials behind it | What that evidence covers | |
|---|---|---|---|
| Melanotan II | No, not for anything | Four, 43 men, 1996 to 2000 | Erections in men. Skin colour, in three of them |
| PT-141 | Yes, since 2019, for one group | Two phase 3 trials, 1,267 women | A desire questionnaire in premenopausal women |
| KPV | No | None, in any species | Gut inflammation in rodents and cells in a dish |
The last column is the one to read. The middle row's approval is real, and it is an approval for desire in premenopausal women, which is not who is holding the vial.
Where it stands with regulators
Melanotan II holds no FDA approval for any indication. It is not named anywhere on the 2026 WADA Prohibited List either, and falls under the S0 catch-all for substances with no current approval by any governmental regulatory health authority for human therapeutic use, prohibited at all times.
FDA wrote to Tailor Made Compounding LLC of Nicholasville, Kentucky on 1 April 2020, reference 594743, after an inspection running 20 August to 24 October 2018, and under the heading "Failure to Meet the Conditions of Section 503A" it lists Melanotan II among the bulk drug substances the firm had compounded with, the stated reason being the three-part 503A test: not the subject of an applicable USP or NF monograph, not a component of an FDA-approved human drug, and not on the 503A bulks list. That is eligibility for a statutory exemption rather than a finding about safety or effect, and the letter went to one pharmacy about its own compounding, so read it as a document about that firm rather than an action against melanotan II itself or against anyone else selling it.
Where the dose came from
What circulates on protocol pages is a loading phase of 250 to 500 mcg subcutaneously daily, up to 1,000 mcg on some as nausea tolerance improves, then maintenance at 500 mcg twice weekly or 250 mcg once or twice weekly, usually paired with UV exposure. Convention, reported as convention. The ultraviolet exposure in that sentence means a sunbed or the sun, the pairing that turns up in almost every harm report below. The three later trials used 0.025 mg/kg, about 1.75 mg for a 70 kg adult, and the 1996 phase I ran 0.01 to 0.03 mg/kg, roughly 0.7 to 2.1 mg at that weight, so what circulates is between a seventh and a third of what anybody was given.
I could not trace it to a derivation. One page says the figures are extrapolated from the published research range, then names no publication for them; another concedes in its fine print that "No FDA-approved dose exists. Loading and maintenance models are community-derived and informed by small early-phase studies."
What could go wrong
What follows is every published human harm I could locate, counted carefully.
A 39-year-old man injected 6 mg of internet-purchased melanotan II subcutaneously, six times the recommended starting dose, and developed sympathomimetic toxicity with heart rate to 146 bpm, creatinine 2.25 mg/dL and creatine phosphokinase peaking at 17,773 IU/L, which is muscle dissolving and passing through the kidneys. Sympathomimetic toxicity is the body behaving as though flooded with adrenaline. Three days in intensive care (PMID 23121206).
Priapism means an erection that will not go down on its own; aspiration means drawing the blood back out with a needle. One case describes acute ischemic priapism after a subcutaneous injection that failed aspiration, irrigation and intracavernous phenylephrine and needed operative penoscrotal decompression, whose authors note that priapism after melanotan II had been reported only twice before (PMID 33460908). A separate case reports low-flow priapism after an abdominal subcutaneous injection, managed with aspiration, irrigation and intracavernosal phenylephrine (PMID 30796078), and I cannot tell whether that one is among the two the first was counting, so do not read three separate men into this paragraph. Two more stand alone: a renal infarction attributed to melanotan II, the authors framing that attribution as possible rather than established (PMID 31953620), and posterior reversible encephalopathy syndrome, Kaski and colleagues in Annals of Internal Medicine in 2013 (PMID 23648958). A renal infarction is a piece of kidney dying because its blood supply closed off.
Then the pigment cells. Naevi are moles, and dysplastic means abnormal looking under a microscope. A 2017 review of unregulated alpha-MSH analogue use counted four case reports of melanomas emerging from existing moles during or shortly after melanotan use, and named changes in existing moles and newly emerging dysplastic naevi as the characteristic skin complication (PMID 28266027). A 20-year-old woman with fair skin was diagnosed with biopsy-confirmed melanoma in the gluteal region after three to four weeks of self-injection alongside sunbed use (PMID 24355990). A 22-year-old woman developed a mass in the anterior maxilla, histologically malignant melanoma, after using melanotan II nasal spray to tan (PMID 40210573); that spray is sold commercially and I found no human study of melanotan II by that route. And a 2026 report describes five separate primary melanomas in situ in one patient, within severely dysplastic naevi, in someone using melanotan I and II products labelled research use only alongside tanning beds and anabolic hormones (PMID 42328529).
Those may overlap, since I cannot tell which cases the 2017 review's four already counted, so I am not adding them up.
What nobody knows
Whether the drug caused any of the cases above. No cohort, no case-control, no registry analysis, and nearly every reported patient also used a sunbed or chased the sun. A cohort follows a group of users forward and records what happens; a case-control starts with the people who got the disease and looks back.
How long a dose lasts in a person is the other thing I could not find. The only pharmacokinetic study I located was in rats, 0.3 mg per kilogram intravenously (PMID 7981427), and the half-life numbers on vendor pages have no human source I could locate. Pharmacokinetic means how fast a dose is taken up, spread through the body and cleared again. Intravenously means straight into a vein, not the route on any protocol page.
Whether it does anything in a woman. Go back to the four published trials. All four enrolled men only, and I found no trial in women.
Whether the amounts people actually inject do anything at all. Every published dose sits well above what circulates, and I found no study of the smaller figures.
My take
For most entries here I end up writing that nobody looked. This time they did, and what came back is above: intensive care, surgery after drug treatment failed, and melanoma in young fair-skinned people who were also using sunbeds. None of that establishes cause. But an empty file and a file with things in it are two different kinds of unknown, and this is the one where I want the cohort study.
The other thing I keep turning over is that it worked. Seventeen of twenty men, no stimulation required. Rather than develop melanotan II, the programme went to bremelanotide, sold as VYLEESI, which differs from it only at one end of the molecule, a free acid where melanotan II carries an amide. Approved in 2019, and it now ships in an autoinjector. I found no published account of why. And the only registered melanotan II trial I could find on ClinicalTrials.gov is a piece of fiction that says so in its first sentence, still recruiting five months after posting.
If you have run melanotan II, did anyone photograph your moles before you started?
Frequently asked
Does melanotan II actually make you tan?
The published human record for skin colour is three men. That is the whole of it that I could find.
Is melanotan II approved by the FDA?
No. Melanotan II holds no FDA approval for any indication.
Does melanotan II cause melanoma?
That question has not been settled by a study. I could find no cohort or case-control study, and nearly every reported patient also used a sunbed, so none of it establishes cause.
This content is for educational and informational purposes only and is not medical advice. Peptides discussed are research compounds and may not be approved for human use. Nothing here should be used to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any peptide, supplement, or protocol. Individual responses vary. Do not self-administer compounds without proper medical supervision.
Registrations not to cite
- NCT07437560
Melanotan II (MT-II) as an Adjunct to NB-UVB Phototherapy for Repigmentation in Stable Nonsegmental Vitiligo
The registry lists it as recruiting, Hudson Biotech, first posted 27 February 2026.
Declares itself fictional in its own opening words: the summary and description both begin as an example interventional study record. Hudson Biotech, Shenzhen.
Registry details are from ClinicalTrials.gov, the United States government trial registry, as it read on 14 September 2026.
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