Melanotan II Half-Life: How Long It Stays in Your System

Melanotan II half-life

Half-life: no published half-life found (PubMed search, 2 Oct 2026). A half-life depends on the route (under the skin, into a vein, by mouth or nasal spray), so we report it per route with the study it came from.

What half-life means

Half-life is the time it takes for the amount of a drug in the blood to fall by half. After one half-life, about 50% is left; after two, about 25%; after four to five, only a few percent remain.

• A long half-life lets a drug be dosed less often, for example once a week.
• A short half-life means levels rise and fall quickly, which is why some peptides are given daily or more often.
• Effects can outlast blood levels, so half-life alone does not tell you how long a drug works.

What it means for dosing frequency

Dosing intervals used in published studies of Melanotan II:

• daily Monday to Friday, subcutaneous (Human controlled trial; Life sciences 1996, PMID 8637402)
• 10 min before each paced mating test, intravenous (Animal · rat; Pharmacology, biochemistry, and behavior 2006, PMID 17113634)

Changing the interval changes how much drug builds up between doses, so it is not a free choice.

Drug tests and sport

Melanotan II: This is not named on the 2026 list. The catch-all class S0 prohibits any drug with no approval anywhere for human use, so it would be banned if no health authority has approved it, but we have not verified that for this substance.

Anti-doping labs use tests built for specific substances. Whether a given test detects Melanotan II, and for how long, is not reported in the anti-doping literature we checked (as of 2 Oct 2026).