Last evidence review: August 27, 2026
Melanotan II, also called MT-II, is a synthetic cyclic peptide studied as a melanocortin-receptor agonist. FDA’s substance record identifies it as a distinct N-acetylated cyclic heptapeptide with an amidated C-terminus.[1]
Melanotan II is not Melanotan I or afamelanotide. It is also not bremelanotide, the active ingredient in the FDA-approved finished drug Vyleesi. Similar names and related melanocortin pharmacology do not make these molecules or products interchangeable.
Direct human evidence for Melanotan II is limited to small early studies. No FDA-approved finished Melanotan II drug was identified. This page separates molecular identity, early human research, and current FDA compounding records. It does not provide medical advice or use instructions.
Identity at a glance
| Field | Evidence-checked record |
|---|---|
| Preferred name | Melanotan II |
| Common alias | MT-II |
| FDA UNII | UPF5CJ93X7 |
| Molecular class | N-acetylated cyclic heptapeptide |
| Parent formula | C50H69N15O9 in the FDA GSRS record |
| Related form | FDA also maintains a related Melanotan II acetate record |
| U.S. status | No FDA-approved finished drug identified |
| Catalog-material status | Exact form and lot identity require separate verification |
A UNII identifies a substance record. It is not FDA approval, evidence of purity, or verification of a seller’s product.
How does Melanotan II differ from Melanotan I and bremelanotide?
Melanotan I/afamelanotide is a linear 13-residue alpha-MSH analogue. Melanotan II is a shorter cyclic peptide. Bremelanotide is another distinct cyclic peptide with different terminal chemistry and is the active ingredient in a named FDA-approved finished drug; FDA maintains separate substance records for Melanotan II and bremelanotide.
Those structural and regulatory differences mean evidence cannot be borrowed across the three records. A result for afamelanotide or bremelanotide is not a result for Melanotan II.
What has been studied in laboratory and animal models?
Melanotan II is used in receptor, cell, and animal experiments examining melanocortin signaling. Depending on the model, researchers have measured pigmentation, feeding, neuroendocrine, or behavioral endpoints.
These studies can help characterize a pathway. They do not establish a clinical use, long-term human outcome, or the identity and performance of a commercial sample.
Evidence tier: E, Laboratory evidence or D, Animal evidence, depending on the experiment.
What did the first human pilot study examine?
A 1996 single-blind, placebo-controlled pilot enrolled three healthy male volunteers and measured pigmentation and short-term physiological observations.[2]
Three participants are insufficient for a reliable estimate of benefit, risk, generalizability, or long-term outcomes. The study should be described as early human-exposure evidence, not proof of a clinical or cosmetic claim.
Evidence tier: C, Limited human evidence.
What did the placebo-controlled erectile-response study find?
A double-blind, placebo-controlled crossover study enrolled ten men with psychogenic erectile dysfunction and measured short-term penile rigidity. The study reported a difference on the instrumented endpoint and more transient symptoms after Melanotan II.[3]
The evidence remains preliminary. The trial was tiny, observed a short window, enrolled a narrow population, and measured a physiological surrogate rather than a broad patient-centered outcome. It did not establish an approved use, comparative effectiveness, or a long-term benefit-risk profile.
Evidence tier: C, Limited human evidence.
What is the current FDA status?
No FDA-approved finished drug containing Melanotan II was identified. FDA enforcement records have described the substance as unapproved. FDA’s current compounding safety-risk page also says compounded drugs containing Melanotan II may present immunogenicity concerns related to aggregation or peptide impurities and points to serious-event reports in the literature.[4][5]
FDA’s May 2026 bulk-substance update says Melanotan II was removed from Category 2 because the nominations were withdrawn and that FDA intends to consult the Pharmacy Compounding Advisory Committee about potential inclusion on the 503A Bulks List.[6]
That procedural removal is not FDA approval, endorsement, or a finding that Melanotan II is safe or effective.
Status checked: August 27, 2026.
Important evidence limits
- The direct human studies were extremely small and short.
- Human physiological or pigmentation measurements are not evidence of broad clinical benefit.
- Receptor and animal studies cannot be treated as human outcomes.
- Melanotan II, afamelanotide, and bremelanotide are distinct molecules and regulatory records.
- A withdrawn compounding nomination does not establish approval or safety.
- No cited paper establishes the identity, quantity, purity, stability, sterility, or performance of a Serum Research lot.
Frequently asked questions
Is Melanotan II the same as Melanotan I?
No. Melanotan II is a shorter cyclic peptide. Melanotan I is an older name mapped to afamelanotide, a linear 13-residue analogue.
Is Melanotan II the same as bremelanotide or PT-141?
No. They are distinct molecular records. Evidence and regulatory status for bremelanotide do not transfer to Melanotan II.
Is Melanotan II FDA approved?
No FDA-approved finished Melanotan II drug was identified in the current review. FDA has described it in unapproved-drug and compounding-risk records.
Does a UNII mean FDA approved?
No. A UNII is an identity code. FDA states that UNII availability does not imply regulatory review or approval.
What kind of human evidence exists?
The direct published record includes very small early studies measuring pigmentation, short-term physiological observations, and erectile-response endpoints. Those studies are preliminary and do not support broad claims.
Does this page explain how to use Melanotan II?
No. It is an evidence and identity summary and intentionally includes no personal-use instructions.
Primary and official sources
- FDA UNII record for Melanotan II, UPF5CJ93X7
- Pilot phase 1 study, PMID 8637402
- Double-blind placebo-controlled crossover study, PMID 9679884
- FDA compounding safety-risk page
- FDA warning letter describing the approval and compounding boundary
- FDA 503A bulk-substance category update, May 14, 2026
- FDA UNII record for bremelanotide, 6Y24O4F92S
- FDA Vyleesi approval letter, NDA 210557
Suggested internal links after publication: Research Library hub; how we review evidence; Melanotan I and afamelanotide; bremelanotide/PT-141; approved drug versus research material; quality testing. No catalog link until the gate below passes.