Melanotan II

What the compound is

Melanotan II, often shortened to MT-II or MT-2, is a cyclic peptide analogue investigated for melanocortin-receptor activity. The early development programme examined both pigmentation and erectile responses. It should not be confused with melanotan I / afamelanotide or with bremelanotide: research on a related molecule cannot be assigned to MT-II solely because the names or receptor family overlap. [1][2]

The pigmentation pilot

The 1996 phase 1 pilot involved only three male volunteers. Two showed increased pigmentation, while reported effects included nausea, fatigue, yawning and erections. This demonstrates an early biological signal with tolerability findings. Three participants cannot establish a safe commercial tanning intervention, identify uncommon harm or show protection from ultraviolet damage. [1]

The important distinction is between stimulating pigment and preventing sun-related injury. The study did not establish a substitute for sun protection, and its monitored subcutaneous research protocol does not validate a nasal product.

Other human research

A double-blind crossover study in ten men with psychogenic erectile dysfunction reported erectile responses more often after MT-II than placebo. It also reported nausea and other transient effects. The study’s small size, selected population and short observation window constrain what it can establish. [2]

A later report summarised the investigators’ experience across twenty men, including both psychogenic and organic erectile dysfunction. It provides context for melanocortin signalling but should not automatically be counted as twenty additional independent participants beyond earlier reports. Historical clinical activity is not equivalent to an approved treatment indication. [3]

Vial and nasal spray: different evidence questions

Leni lists a vial and a nasal spray. A shared compound name does not establish equivalent absorption, formulation, delivered amount or quality. The historical studies reviewed here do not test those Leni products. [6]

In August 2026, the TGA reported testing five nasal-spray bottles from a separate supplier: estimated contents ranged from 22 to 54 mg despite a 30 mg label. This is evidence about the seized products, not a test of Leni’s stock. It illustrates why a labelled amount or a convenient delivery format cannot substitute for verified product-specific evidence. [5]

Human-use context and safety

The TGA states that Melanotan II is prescription-only in Australia, that no products containing it are included in the ARTG or approved for supply, and that it is not approved as a tanning agent. It advises consumers against use. These are the relevant Australian boundaries for interpreting the historical research. [5]

A published case report describes renal infarction temporally associated with MT-II exposure and discusses possible mechanisms. A case report can flag a serious safety signal but cannot measure the incidence of harm or conclusively establish causation. [4] Together with adverse effects in the early trials, this makes a positives-only account incomplete. There is no established human-consumption, nasal-spray or tanning protocol that can responsibly be derived from the reviewed sources. [1]