Melanotan II, PT-141 & Kisspeptin

Melanotan II, PT-141 and Kisspeptin are research peptides that act on receptors of the hormonal system. Melanotan II and PT-141 belong to the melanocortin peptides and are closely related in structure. Kisspeptin is a signalling peptide of the reproductive axis. This category contains all three as lyophilised powder for laboratory research.

Melanocortin and Kisspeptin peptides in this category

• Melanotan II 10 mg: a cyclic analogue of the hormone alpha-MSH. It activates several melanocortin receptors, including MC1R, which controls the pigment melanin in skin cells.
• PT-141 10 mg: also called Bremelanotide, a metabolite of Melanotan II. It acts mainly on the MC4R receptor in the brain. Bremelanotide is an approved medicine in the US for one specific indication.
• Kisspeptin 5 mg: a peptide that controls the release of GnRH in the hypothalamus. It is studied in reproductive endocrinology and puberty research.

Melanotan II vs PT-141: the difference

Melanotan II and PT-141 share most of their structure. PT-141 differs by one chemical group, and this small change shifts its receptor profile. Melanotan II activates MC1R strongly, which is why it is studied for pigmentation. PT-141 has little effect on MC1R and acts mainly on MC4R, which is why it is studied in the nervous system. For receptor research, the pair is a useful comparison of how a small change in structure changes the biological target.

Kisspeptin is not a melanocortin peptide. It is included here because it is studied in the same field of hormonal signalling and is often requested together with the other two.

Handling of these research peptides

All three compounds are supplied as lyophilised powder in sealed vials. Melanotan II and PT-141 are relatively stable peptides. Kisspeptin is supplied in a smaller 5 mg vial because it is active at low amounts. All are dissolved before use with bacteriostatic water, as explained in our guide on how to reconstitute peptides.

Regulatory status of Melanotan II and PT-141

Melanotan II is not an approved medicine in any country, and several health authorities have issued warnings about unregulated products. Bremelanotide is approved in the US, but the research compound sold here is not a pharmaceutical product. All products in this category are sold for laboratory research use only and are not intended for human or veterinary use.