This page compares what is documented about Melanotan I and Melanotan II, rather than ranking them by effect. What each molecule is, the sizes and prices actually carried, what the certificate covers, and how the two differ on the bench. Everything here is research-use-only material and we do not publish outcome, dosing or administration content for any compound in the catalogue.
What is Melanotan I and what is Melanotan II?
Melanotan I. Melanotan I is a linear analogue of alpha-melanocyte-stimulating hormone. It is a distinct molecule from Melanotan II, which is cyclic, and the two are routinely conflated in supplier listings.
Melanotan II. Melanotan II is the original synthetic melanocortin analogue from the University of Arizona programme — still cited as the reference non-selective agonist in receptor studies.
How do Melanotan I and Melanotan II compare on price and size?
| Melanotan I | Melanotan II | |
|---|---|---|
| Sizes carried | 10 mg | 10 mg |
| From | $40.00 | $35.00 |
| Best price per unit | $4.00 / mg | $3.50 / mg |
| Availability | Backordered — waitlist | Backordered — waitlist |
| Certificate | Lot certificate on the product page | Lot certificate on the product page |
| Molecular formula | C78H111N21O19 | C50H69N15O9 |
| Molar mass | 1,646.8 g/mol | 1,024.2 g/mol |
| Source | PubChem CID 16197727 | PubChem CID 92432 |
| Research area | melanocortin receptor pharmacology | melanocortin research |
At their best sizes Melanotan II works out at $3.50 per mg against $4.00 for Melanotan I — 14% more for the mg. Vial prices start at $40.00 and $35.00 respectively, which is the number most people compare and the one that says least, because the two are not sold in the same sizes. Full sizes, tier pricing and the lot certificate sit on the Melanotan I page and the Melanotan II page.
What is each one studied for?
What the published literature investigates, which is a different question from what either will do, and the only one of the two a supplier can answer.
Melanotan I is studied in melanocortin receptor pharmacology research. Melanocortin receptor pharmacology remains an active area, and the structural difference between linear and cyclic analogues is a standard teaching example.
Melanotan II is studied in melanocortin research. Non-selective melanocortin agonists remain standard tools in receptor-pharmacology work, with Melanotan II the most-cited of them.
Studied in the same area does not make two compounds interchangeable, and the research library holds the per-compound documentation.
Melanotan 2 vs Melanotan 1: how they differ on the bench
Melanotan II. MT-II's lactam bridge is what our identity work verifies; the linear precursor is a different compound that a bare mass check can miss.
Melanotan I. Where two products in a category share most of a name, the certificate is the only thing that tells them apart. Ours names the sequence rather than the marketing term.
On naming, because the two are written several ways and the difference is not always obvious: Melanotan I is also written melanotan 1; Melanotan II is also written melanotan 2. They refer to the same materials described here, and the certificate for a lot uses the name on this page. The comparison itself is usually typed Melanotan 1 vs 2.
What actually differs between Melanotan II and Melanotan I
Worth doing the arithmetic before comparing sizes: Melanotan I is 1,646.8 g/mol and Melanotan II is 1,024.2 g/mol, a factor of 1.6. A milligram of Melanotan II therefore contains roughly 1.6 times as many molecules as a milligram of Melanotan I, so two vials of the same labelled mass hold quite different amounts of substance. Equal milligrams are not equal moles, which is what the molarity calculator exists to convert, and it is the reason a price-per-milligram comparison and a price-per-mole comparison can point at different vials.
Identity is the other analytical axis, and it is settled per lot rather than per compound. Melanotan II. Catalogued as Melanotan II, and the certificate's identity test resolves to that.
Both are released against a certificate reporting identity, purity by the stated method and net peptide content, readable before anything is bought.
Which is better, Melanotan 2 or Melanotan 1?
Neither Melanotan 2 nor Melanotan 1 is ranked against the other here, and the refusal is deliberate. Better, safer and stronger are questions about effects in a living system, and we sell neither compound for use in one — why none of these pages ranks two compounds sets out the reasoning in full.
What it does instead, for these two:
- Melanotan II is the cheaper of the two per mg, at $3.50 against $4.00.
- Melanotan I is the heavier molecule by a factor of 1.6, so equal milligrams are not equal moles.
- Both are carried in 1 size, and each lot carries its own certificate.
Every one of those is checkable before you buy.
Common questions
What is the difference between Melanotan II and Melanotan I?
Different molecules before anything else: Melanotan II is C50H69N15O9 and Melanotan I is C78H111N21O19. Melanotan II is the original synthetic melanocortin analogue from the University of Arizona programme — still cited as the reference non-selective agonist in receptor studies. Melanotan I is a linear analogue of alpha-melanocyte-stimulating hormone. It is a distinct molecule from Melanotan II, which is cyclic, and the two are routinely conflated in supplier listings.
Which one should I choose?
Melanotan I is carried in 10 mg and Melanotan II in 10 mg, each lot with its own certificate. Which of those suits the work is yours to decide; everything here is research-use-only rather than guidance for use in a human or an animal.
Do both Melanotan I and Melanotan II come with a certificate of analysis?
Neither is in stock at the moment, so in each case the certificate is the one attached to the lot that arrives. A certificate belongs to a lot, not to a product. It is linked from the product page, and reports identity, purity by the stated method, and net peptide content for the material actually in that lot.
Which is cheaper, Melanotan II or Melanotan I?
Per mg, Melanotan II at $3.50 against $4.00, taking each one's best size. By vial they start at $40.00 for Melanotan I and $35.00 for Melanotan II, which is the comparison most people make and the one that says least, because the two are not sold in the same sizes.
Is a milligram of Melanotan I the same as a milligram of Melanotan II?
By mass yes, by amount of substance no. Melanotan I is 1,646.8 g/mol and Melanotan II is 1,024.2 g/mol, a factor of 1.6, so a milligram of Melanotan II holds roughly 1.6 times as many molecules. Two vials with the same number on the label are not the same amount of substance, which is what the molarity calculator converts.
FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. NOT FOR PERSONAL, MEDICAL, DIAGNOSTIC, THERAPEUTIC, OR RECREATIONAL USE.