Melanotan 2 Dosage: What the Studies Used

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This page reports Melanotan 2 dosage only as a record of how published studies were run. It is not a protocol and not advice. Melanotan 2 is not approved for human use anywhere ^[3], and nothing here tells anyone to take anything.

When a number appears below — a milligram-per-kilogram figure, a route, a schedule — it describes the design of a specific experiment in a specific species. Read "0.025 mg/kg subcutaneously" as "this is what one trial administered," not as a dose to copy. Doses in animals are often given by routes (such as injection straight into the brain) that have nothing to do with how the compound is used outside the lab. The point of the page is to show what has actually been measured and how, not to instruct.

Doses used in the human studies

The controlled human data come from two small early studies. In the pilot Phase I pigmentation study, 3 male volunteers received subcutaneous Melanotan 2 escalated from 0.01 to 0.025-0.03 mg/kg, dosed every other weekday for two weeks; the authors noted dose-limiting somnolence (drowsiness) at 0.03 mg/kg and proposed 0.025 mg/kg/day as the dose for future Phase I work ^[1]. In the erectile-dysfunction crossover study, 10 men received a single subcutaneous dose of 0.025 mg/kg ^[2]. These are study-design facts. No larger or later-phase trial established any dose, and the compound has no approved dose in any jurisdiction ^[3].

Doses used in the animal studies

Animal work used routes and amounts specific to each experimental question. For appetite, mice received 0.1, 0.3, or 1 nmol microinjected directly into the nucleus accumbens ^[5]. Rat appetite and axis studies used central (intracerebroventricular) co-infusion ^[10]. A physicochemical study reported an oral bioavailability of only 4.6% in the rat, which is why oral dosing is not a practical research route ^[7]. None of these amounts translates to a human dose; they are tools for probing a mechanism in a model organism.

Melanotan 2 injections

Across the literature, Melanotan 2 injections mean subcutaneous (under-the-skin) administration — the route used in both human studies ^[1], ^[2] and the primary route in self-administration case reports. Intravenous dosing appears in rodent pharmacokinetic and behavioral work ^[9], and intranasal sprays are documented in unlicensed self-administration reports. The injectable route exists because the peptide is almost inactive by mouth (about 4.6% oral bioavailability in the rat) ^[7]. The case-report harms — priapism, renal infarction, rhabdomyolysis — are all reported in the context of self-administered injections ^[4], ^[25], underscoring that injecting an unregulated product carries risk independent of any intended effect.

Melanotan 2 half life

No validated human pharmacokinetic half-life has been published for Melanotan 2 itself. A rat intravenous study showed biphasic, rapid multi-compartment plasma clearance ^[41]. By way of comparison, the closely related linear analog Melanotan I (afamelanotide) in humans had an absorption half-life of roughly 0.07-0.79 hours and a beta-phase (elimination) half-life of roughly 0.8-1.7 hours after subcutaneous dosing.

The key point is that the visible effect long outlasts the molecule. In both compounds, pigmentation persists for weeks after the peptide has cleared, because melanin synthesis continues downstream once the receptor signal has fired. A short chemical half-life does not mean a short-lived effect — the tan, and the mole changes, can persist well after dosing stops, which the discontinuation reports on the Melanotan 2 effects page describe.

Stability as reported

Melanotan 2 is described as a lyophilized (freeze-dried) powder that is stable kept cold and dry; reconstituted solutions are typically refrigerated at about 4 °C per general peptide-laboratory practice. Its lactam-bridged cyclic structure — an internal chemical bond closing the peptide into a ring — gives it more resistance to enzymes than linear alpha-MSH. Preformulation data report pKa values of 6.54 (histidine) and 11.72 (arginine) and an octanol/water log partition coefficient of 2.82 ^[7]. These are laboratory handling characteristics, not preparation instructions.