Melanocortin & Tone

Melanotan II

Melanocortin Receptor Agonist - Melanocortin agonist studied for pigmentation research.

Melanotan II is a synthetic analog of alpha-melanocyte-stimulating hormone, studied for its non-selective activation of melanocortin receptors in pigmentation research.

Melanotan II is a broadly acting melanocortin agonist, and because it engages several receptors it is studied both for pigmentation (MC1) and other melanocortin-linked endpoints. The FDA has warned about products containing it, underscoring its research-only status here.

Melanotan II specifications

CAS number

121062-08-6

Molecular formula

C50H69N15O9

Molecular weight

1024.18 g/mol

Sequence

Cyclic melanocortin heptapeptide

Residues

7 residues (cyclic)

Presentation

Lyophilized powder

Documented purity

99.59% by HPLC

Available sizes

10mg ($30)

Archived COA lots

4

Intended use

Laboratory research use only. Not for human or veterinary use.

Studied pathways

• Melanocortin agonism - Studied for melanogenesis via melanocortin-receptor activation.

Reported mechanisms in the literature

• MC1-R agonism - A synthetic analog of α-melanocyte-stimulating hormone studied for non-selective melanocortin-receptor activation and melanogenesis signaling. (Hadley et al.)

What Melanotan II is researched for

• Melanogenesis - Studied for melanogenesis via non-selective melanocortin-receptor activation. (Hadley et al.)
• Receptor pharmacology - Investigated as a broadly acting melanocortin agonist in receptor research. (Dorr et al.)

Melanotan II certificates of analysis on file

Every lot below was tested by an independent laboratory and the full report is published as a PDF. Purity is shown exactly as the report states it. The same records are searchable in the COA library and can be checked on the lot verification page.

Published literature on Melanotan II

The mechanisms above trace to peer-reviewed studies indexed on PubMed. These are independent third-party publications, not Aspect Peptides claims. Browse indexed research on PubMed.

Research notes

Research notes: Melanotan II

Background

Melanotan II is a cyclic heptapeptide analog of alpha-MSH, designed to be far more potent and stable than the native hormone. It is a non-selective melanocortin agonist, active at several of the five melanocortin receptors (MC1, MC3, MC4 and MC5), which is why it appears in pigmentation research (MC1) and in other melanocortin-linked endpoints. The development history and early human work are reviewed by Hadley and Dorr (2006), and a pilot phase I evaluation was published in 1996 (Dorr et al.). The FDA has warned consumers about unapproved melanotan products, so this material is supplied strictly for in-vitro laboratory research.

What the Aspect certificates show

There are 3 certificate records for the 10mg vial, all from Freedom Diagnostics, dated 20 February 2026 to 15 September 2026. Reported HPLC purity runs from 99.42% to 99.93%. Identity is confirmed by LC-MS/MS, and the appearance is reported as white lyophilized powder. Each full report is available as a PDF on this page and in the COA library.

How it differs from related compounds

PT-141 is a related cyclic melanocortin analog studied for its MC4 receptor activity, so it is the comparator when receptor selectivity is the question. KPV comes from the same alpha-MSH family but is studied for the opposite property: anti-inflammatory activity without melanocortin-receptor engagement.

Citations

Hadley ME, Dorr RT, Peptides 2006 (PMID 16412534). Dorr RT et al., Life Sci 1996 (PMID 8637402).

Third-party publications are cited for context and are not Aspect Peptides claims. For laboratory research use only.

Melanotan II frequently asked questions

Documented to 99.59% purity by HPLC · third-party COA every lot · from $30 · For laboratory research use only.

Related Melanocortin & Tone compounds

• PT-141 - Bremelanotide - MC4 receptor agonist studied in melanocortin signaling.
• Kisspeptin - Upstream regulator of the reproductive hormone axis.