Melanotan II (MT-2)

Melanotan II (MT-2) is a synthetic cyclic α-MSH analog with broader melanocortin receptor binding than Melanotan I, producing skin pigmentation, sexual function effects, and appetite suppression through engagement of multiple melanocortin receptors. It is the parent compound from which PT-141 (bremelanotide) was derived as the FDA-approved selective MC4R agonist for sexual desire disorder. Important regulatory update: Melanotan II was removed from the FDA's Category 2 bulk substances list on April 22, 2026 and is scheduled for PCAC review in early 2027.

What is Melanotan II and how does the broad melanocortin receptor mechanism work?

Melanotan II is a synthetic cyclic 7-amino-acid α-MSH analog (cyclic via lactam bridge) that binds multiple melanocortin receptors: MC1R (melanocyte pigmentation), MC3R (energy homeostasis), MC4R (sexual function, appetite), and MC5R (exocrine function). The broad receptor engagement produces multiple effects including skin pigmentation, sexual arousal, appetite suppression, and occasional nausea/flushing. The cyclic structure differentiates MT-2 from the linear Melanotan I.

Evidence level: preclinical extensive; community/cosmetic use extensive; PT-141 (MT-2-derived) FDA-approved

What does the research show for Melanotan II?

Preclinical studies have demonstrated the broad melanocortin receptor effects across pigmentation, sexual function, and appetite. Melanotan II's own human record is small and dates to the 1990s University of Arizona program: in a double-blind, placebo-controlled crossover study, subcutaneous MT-II (0.025 mg/kg) initiated erections in 8 of 10 men with psychogenic erectile dysfunction — mean duration of ≥80% rigidity 38.0 minutes vs 3.0 on placebo — with nausea, stretching and yawning, and decreased appetite as the reported side effects. MT-II itself was never taken through to approval. Development shifted to the closely related compound PT-141 (bremelanotide), which completed Phase 3 and earned FDA approval as Vyleesi (2019) for hypoactive sexual desire disorder in premenopausal women; the Vyleesi label describes bremelanotide as a nonselective melanocortin-receptor agonist whose MC1R and MC4R activity is most relevant at therapeutic doses. Melanotan II itself has not advanced to formal regulatory approval; it remains widely used in community and cosmetic contexts. The Melanotan II MC1R/MC4R science article covers the receptor pharmacology in depth.

Sources: Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study, Wessells H., Fuciarelli K., Hansen J., Hadley M.E., Hruby V.J., Dorr R., Levine N., J Urol, 1998; VYLEESI (bremelanotide injection) — US Prescribing Information, Cosette Pharmaceuticals (labeler), via DailyMed · Evidence level: preclinical extensive; community/cosmetic use; MT-2-derived PT-141 FDA-approved

How does Melanotan II compare to Melanotan I and PT-141?

Melanotan II is the broad-receptor cyclic analog from which the selective MC4R agonist PT-141 was derived; it differs from Melanotan I by cyclic structure and broader receptor binding. The Melanotan 1 vs Melanotan 2 comparison walks the differences receptor by receptor.

What are the documented side effects of Melanotan II?

Common side effects in community use include nausea, flushing, mild hypertension, and occasional spontaneous penile erection (a melanocortin pathway effect). The broad receptor binding produces a more variable side effect profile than the selective MC4R agonist PT-141. Melanoma risk is a theoretical concern given melanocyte stimulation, with case reports of new or changing nevi documented in community use. Long-term safety at sustained dosing is not characterized at Western RCT standards.

Evidence level: small 1990s trial safety data; published case reports of serious harms (rhabdomyolysis, priapism, renal infarction, PRES, melanoma); long-term unestablished

What is the regulatory status of Melanotan II?

Melanotan II is not approved for any medical or cosmetic indication anywhere in the world as of August 2026. On April 22, 2026 (notice April 15, effective within seven days), Melanotan II was one of twelve peptides removed from the FDA's Category 2 bulk-substances list because — in FDA's words — their nominations were withdrawn by the nominators; FDA's "nominated but withdrawn" table still flags that compounded melanotan II "may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation or peptide-related impurities." It is slated for Pharmacy Compounding Advisory Committee (PCAC) consideration before the end of February 2027, alongside LL-37, dihexa acetate, injectable GHK-Cu, and PEG-MGF. Removal from Category 2 does not authorize compounding pharmacy production. Outside the US the direction of travel is enforcement, not accommodation. In Australia, melanotan I and II are Schedule 4 prescription-only medicines, selling or advertising them as tanning products is illegal, the TGA has warned consumers against melanotan tanning products, and in May 2026 it fined one NSW-based supplier A$101,412 across 27 infringement notices for alleged unlawful supply of Melanotan II. In the UK, the MHRA treats melanotan products marketed with medicinal claims as unlicensed medicines and states it has "repeatedly taken action to remove melanotan products… from sale for over 10 years." Current status in FDA peptide regulation 2025–2026 timeline.

Sources: FDA Announces Removal of 12 Peptides from Category 2 (nominations withdrawn by the nominators) and Schedules PCAC Meetings, Orrick (legal analysis of the FDA notice), via Orrick Insights; FDA 503A bulk drug substances (Category 1/2) page; FDA Pharmacy Compounding Advisory Committee meeting scheduled before end of February 2027 — 503A bulks consideration (LL-37, dihexa acetate, injectable GHK-Cu, PEG-MGF, melanotan II), FDA; Illegal tanning nasal sprays pushed by social media influencers, CHOICE (quoting TGA spokesperson; A/Prof D. Sebaratnam), via choice.com.au; Don't risk using tanning products containing melanotan (TGA blog + enforcement), TGA, via tga.gov.au; MHRA FOI 21/1237 — melanotan II: regulatory status, enforcement history, Yellow Card reports, MHRA, via gov.uk (FOI response PDF)

Why does Melanotan II vendor verification matter?

Melanotan II is widely sold in research-grade markets but with substantial quality variance and occasional mislabeling — including substitution with the related but distinct PT-141. Mass spectrometry identity confirmation distinguishes the two. Independent HPLC purity testing is the standard quality signal. The gray market's track record here is measured, not hypothetical: a peer-reviewed LC-UV-MS/MS analysis of melanotan II products bought online found vials containing 4.32–8.84 mg against a uniform "10 mg" label claim, with unknown impurities reaching 4.1–5.9% in products from two of three shops. Identity testing has a subtlety unique to this compound family: MT-II (1,024.2 Da) and PT-141/bremelanotide (1,025.2 Da) differ by roughly one Dalton — a C-terminal amide versus free acid — so distinguishing them takes quality mass-spectrometry work, not a casual HPLC pass. Compare vendors against the independent Melanotan II lab tests on file, and see the where to buy Melanotan II purity and identity checks guide for the full framework. Guidance in how-to-test-peptides hub.

Sources: Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet, Breindahl T., Evans-Brown M., Hindersson P., McVeigh J., Bellis M.A., Stensballe A., Kimergård A., Drug Test Anal, 2015; Melanotan II — compound identity, PubChem (NCBI), PubChem, 2026; Bremelanotide — compound identity, PubChem (NCBI), PubChem, 2026

How does Peptigrity verify Melanotan II vendors?

Peptigrity collects independent third-party Certificates of Analysis for Melanotan II from shops' official channels and verifies each for authenticity before publishing. Because shops choose which COAs to publish, results reflect the batches shops have made public rather than every production batch — a selection bias we state openly. A community-funded Testing Grant to purchase and test vials anonymously is in development. Tests in the database come from independent labs such as Janoshik Analytical, Freedom Diagnostics, and Chromate. Methodology in how we calculate trust scores.

Frequently asked questions

What does Melanotan II do?

Melanotan II binds multiple melanocortin receptors producing skin pigmentation, sexual function effects (including spontaneous erection in some users), and appetite suppression. The broad receptor engagement produces a complex effect profile.

Is Melanotan II legal to purchase?

In many jurisdictions Melanotan II is sold as a research chemical for laboratory use, but it is not approved for human consumption anywhere, and "legal to buy" is shrinking: Australia treats melanotans as prescription-only medicines and fines suppliers who sell them as tanning products, and the UK's MHRA has acted against melanotan sales for over a decade. The April 22, 2026 US Category 2 removal reflects withdrawn nominations, not a safety clearance — it does not authorize compounding; PCAC consideration is slated before the end of February 2027. Country breakdown in peptide legal status guide.

Sources: Illegal tanning nasal sprays pushed by social media influencers, CHOICE (quoting TGA spokesperson; A/Prof D. Sebaratnam), via choice.com.au; MHRA FOI 21/1237 — melanotan II: regulatory status, enforcement history, Yellow Card reports, MHRA, via gov.uk (FOI response PDF); FDA Pharmacy Compounding Advisory Committee meeting scheduled before end of February 2027 — 503A bulks consideration (LL-37, dihexa acetate, injectable GHK-Cu, PEG-MGF, melanotan II), FDA

When will the FDA decide on Melanotan II?

No decision date exists. The FDA has said it will convene its Pharmacy Compounding Advisory Committee before the end of February 2027 to consider Melanotan II for the 503A bulks list. PCAC votes are advisory — FDA staff opposed the peptides considered at the July 2026 meeting, and no recommendation has been finalized into rulemaking — so committee consideration is not an approval, and compounding remains unauthorized meanwhile. Track developments in FDA peptide regulation 2025–2026 timeline.

Source: FDA Pharmacy Compounding Advisory Committee meeting scheduled before end of February 2027 — 503A bulks consideration (LL-37, dihexa acetate, injectable GHK-Cu, PEG-MGF, melanotan II), FDA

Does Melanotan II cause melanoma?

Causality is not established, but the concern is no longer only theoretical: published case reports document melanoma diagnosed after MT-II use — including melanoma in a 20-year-old following a 3–4-week MT-II course combined with sunbeds — and darkening or eruption of naevi is repeatedly reported. Dermatologists note the mechanistic worry directly: stimulating melanocytes could, hypothetically, promote conversion to melanoma. Long-term formal safety studies are absent. Mole changes during or after use warrant a dermatologist visit. Anyone considering Melanotan II use should consult a licensed physician about the underlying melanocortin biology and have any new or changing skin lesions evaluated.

Sources: Melanoma Associated with the Use of Melanotan-II, Hjuler K.F., Lorentzen H.F., Dermatology, 2014; Illegal tanning nasal sprays pushed by social media influencers, CHOICE (quoting TGA spokesperson; A/Prof D. Sebaratnam), via choice.com.au

How does Melanotan II differ from PT-141?

Melanotan II binds multiple melanocortin receptors broadly; PT-141 (Bremelanotide, Vyleesi) was derived from MT-2 as a selective MC4R agonist with FDA approval for hypoactive sexual desire disorder. PT-141 has the focused mechanism and regulatory approval; MT-2 has broader effects without approval.

How can I verify a Melanotan II vendor is selling real product?

Independent third-party HPLC certificate of analysis from a lab the vendor does not own or pay, with mass spectrometry identity confirmation. Mass spec distinguishes MT-2 from related compounds including PT-141. COA interpretation in red flags in peptide certificates of analysis.

Does Peptigrity recommend a Melanotan II dose?

No. Melanotan II is not approved for human consumption and Peptigrity is an independent review platform, not a medical authority. Community-use dosing varies widely. Anyone considering use should consult a licensed physician.

This section is for educational and informational purposes only and does not constitute medical advice. Melanotan II is not approved by the FDA or equivalent regulators for human use. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.