MT-II

What MT-II Is and How It Works Structure and Identity MT-II is a cyclic heptapeptide: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. Formula C50H69N15O9, molecular weight about 1,024, CAS 121062-08-6. The ring is formed by a lactam bridge between aspartic acid and lysine. That ring, plus the D-phenylalanine and norleucine substitutions, protects it from the enzymes that break down natural alpha-MSH within minutes. Where It Came From MT-II came out of a University of Arizona program in the 1980s that set out to build more stable versions of alpha-MSH. The team produced two compounds. Melanotan I is a straight-chain analog. MT-II is the smaller, cyclic one. The rights were later licensed to Palatin Technologies, which ended MT-II development in 2000. The Receptors It Binds MT-II is non-selective. It binds four of the five melanocortin receptors: MC1R, MC3R, MC4R and MC5R. MC1R sits mainly on pigment-producing cells in the skin. MC3R and MC4R sit mainly in the brain, especially the hypothalamus. Because it hits all of them at once, its effects in lab models are broad and hard to separate. That lack of selectivity is the main reason later research moved toward more targeted compounds Its Place in the Melanocortin Family MT-II sits in a family of related molecules. Afamelanotide, formerly Melanotan I, is approved in the EU and US for erythropoietic protoporphyria, a rare light-sensitivity disorder. Bremelanotide, also sold as PT-141, differs from MT-II by a single end group and is approved in the US for one specific indication. MT-II itself has no approval anywhere.

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MT-II has an unusual research history. It was developed with a specific goal, then abandoned, and then became widely used outside of any research setting. That combination is why regulators treat it differently from most compounds in our catalog.

The formal research is small. The University of Arizona group ran a handful of small human studies in the 1990s before development stopped. Since then, most of the published work has been receptor pharmacology, meaning which melanocortin receptors it binds and how strongly. It’s also used as a reference compound when designing more selective molecules.

A second body of literature isn’t research at all. It’s case reports written by doctors treating people who used unlicensed MT-II products. Those reports are the main source of what’s known about its risks, and they are summarized in the next section.

No regulator has approved MT-II for any indication. It holds no registro sanitario with Costa Rica’s Ministerio de Salud. It is supplied here as a research material and nothing else.

Questions about MT-II pricing, vial size, batch documentation, storage, or delivery inside Costa Rica? Our team can confirm current stock, bulk pricing and what the Certificate of Analysis covers before you order.

MT-II is a well-characterized cyclic peptide and a standard reference compound in melanocortin receptor research, with a long published history and a clearly stated regulatory position.

We supply high-purity MT-II and other research peptides with consistent quality, transparent pricing, and reliable local delivery. Every order ships from inside Costa Rica — no customs delays, no import duties.