Melanotan II

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10 mg per vial
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This product is prepared for LABORATORY RESEARCH USE ONLY and may not be used for other purposes.


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Molecular Formula C50H69N15O9
Molecular Weight 1024.2
Monoisotopic Mass 1023.54026884
Polar Area 385
Complexity 1950
XLogP 0
Heavy Atom Count 74
Hydrogen Bond Donor Count 13
Hydrogen Bond Acceptor Count 11
Rotatable Bond Count 17
Physical Appearance Fine White Lyophilized Powder
Stability Lyophilized protein is to be stored at -20°C. It is recommended to aliquot the reconstituted (dissolved) protein into several discrete vials in order to avoid repeated freezing and thawing. Reconstituted protein can be stored at 4°C
PubChem LCSS Melanotan II Laboratory Chemical Safety Summary


CID 92432
CAS 121062-08-6
InChI InChI=1S/C50H69N15O9/c1-3-4-16-36(59-29(2)66)44(69)65-41-25-42(67)55-20-11-10-18-35(43(51)68)60-47(72)39(23-31-26-57-34-17-9-8-15-33(31)34)63-45(70)37(19-12-21-56-50(52)53)61-46(71)38(22-30-13-6-5-7-14-30)62-48(73)40(64-49(41)74)24-32-27-54-28-58-32/h5-9, 13-15, 17, 26-28, 35-41, 57H, 3-4, 10-12, 16, 18-25H2, 1-2H3, (H2, 51, 68)(H, 54, 58)(H, 55, 67)(H, 59, 66)(H, 60, 72)(H, 61, 71)(H, 62, 73)(H, 63, 70)(H, 64, 74)(H, 65, 69)(H4, 52, 53, 56)/t35-, 36-, 37-, 38+, 39-, 40-, 41-/m0/s1
Isomeric SMILES CCCC[C@@H](C(=O)N[C@H]1CC(=O)NCCCC[C@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](NC(=O)[C@@H](NC1=O)CC2=CN=CN2)CC3=CC=CC=C3)CCCN=C(N)N)CC4=CNC5=CC=CC=C54)C(=O)N)NC(=O)C
IUPAC Name (3S, 6S, 9R, 12S, 15S, 23S)-15-[[(2S)-2-acetamidohexanoyl]amino]-9-benzyl-6-[3-(diaminomethylideneamino)propyl]-12-(1H-imidazol-5-ylmethyl)-3-(1H-indol-3-ylmethyl)-2, 5, 8, 11, 14, 17-hexaoxo-1, 4, 7, 10, 13, 18-hexazacyclotricosane-23-carboxamide

2D Structure

Generated by Extreme Peptide with Open Babel, version 2.3.1, (accessed May 20, 2024)

Melanotan II 2D molecular structure vector generated with oBabel


Melanotan II is a synthetic variant of the naturally occurring peptide hormone alpha-melanocyte stimulating hormone (α-MSH)1, which acts to stimulate the production of melanin in the skin – the molecule responsible for hair and skin pigmentation – through a process called melanogenesis2. Naturally occurring α-MSH has also been shown to play a role in feeding, the maintenance of useable and stored energy, and sexual activity through its action as an agonist of melanocortin receptors MC1, MC3, and MC4; MC1 being responsible for skin pigmentation effects, and MC3 and MC4 being responsible for effects on appetite, metabolism, and sexual activity3.

Melanotan II is a cyclic heptapeptide originally developed as a defense against the potential cancer-causing effects of the sun’s ultraviolet radiation through its action of stimulating natural melanin production in the absence of sunlight4, which allows for the sunless darkening of skin tone.

In addition to its promotion of skin tanning, Melanotan II has been shown to be a lipolytic (fat cell-destroying) agent5, a suppressant of appetite6, and a stimulant of libido in animal test subjects7. Melanotan II has demonstrated great efficacy in reducing caloric intake, while eliminating cholesterol and fat stores in obese mice through its targeted metabolic action8.

Product Comparison

Melanotan II and Melatonan I, both synthetic analogues of α-MSH, produce similar effects in terms of skin tanning by binding the MC1 receptor9, though Melanotan II is unique in this family of agents in that it stimulates an aphrodisiac effect (MC3 and MC4), improving libido significantly in test subjects.

PT-141 is structurally similar to the biosynthetic peptide hormone Melanotan II, but has shown to be a potent binding agent of MC3 and MC4 only, showing no affinity for MC1. In animal tests, PT-141 has proven quite effective at correcting sexual dysfunction7, while Melanotan II induces an additional effect on skin tone.

Unlike other agents that have an effect on erectile response, Melanotan II performs no action on the vascular system, but rather induces arousal and heightens sexual desire via the nervous system – binding important receptors in the brain10.


Melanotan 2; Melanotan-2; MT-2; MT-II; Melanotide; Tanexin

Peer-Reviewed Sources:

  1. Dorr, R. T., Lines, R., Levine, N., Brooks, C., Xiang, L., Hruby, V. J., & Hadley, M. E. (1996). Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life sciences, 58(20), 1777-1784. ↩︎
  2. Hadley, M. E., Hruby, V. J., Blanchard, J., Dorr, R. T., Levine, N., Dawson, B. V., & Sawyer, T. K. (1998). Discovery and development of novel melanogenic drugs. In Integration of Pharmaceutical Discovery and Development (pp. 575-595). Springer US. ↩︎
  3. King, S.H.; Mayorov AV; Balse-Srinivasan P; Hruby VJ; Vanderah TW; Wessells H. (2007).“Melanocortin Receptors, Melanotropic Peptides and Penile Erection”. Curr Top Med Chem. 7(11): 1098–1106. ↩︎
  4. Pawelek, J. M. (2001). Approaches to increasing skin melanin with MSH analogs and synthetic melanins. Pigment cell research, 14(3), 155-160. ↩︎
  5. Brito, M. N., Brito, N. A., Baro, D. J., Song, C. K., & Bartness, T. J. (2007). Differential activation of the sympathetic innervation of adipose tissues by melanocortin receptor stimulation. Endocrinology, 148(11), 5339-5347. ↩︎
  6. Vergoni, A. V., & Bertolini, A. (2000). Role of melanocortins in the central control of feeding. European journal of pharmacology, 405(1), 25-32. ↩︎
  7. Allard, J., & Giuliano, F. (2001). Central nervous system agents in the treatment of erectile dysfunction: how do they work?. Current urology reports, 2(6), 488-494. ↩︎
  8. Chen, A. S., Metzger, J. M., Trumbauer, M. E., Guan, X. M., Yu, H., Frazier, E. G., & Van der Ploeg, L. H. (2000). Role of the melanocortin-4 receptor in metabolic rate and food intake in mice. Transgenic research, 9(2), 145-154. ↩︎
  9. Schiöth, H. B., Muceniece, R., Mutulis, F., Prusis, P., Lindeberg, G., Sharma, S. D., & Wikberg, J. E. (1997). Selectivity of cyclic [D-Nal 7] and [D-Phe 7] substituted MSH analogues for the melanocortin receptor subtypes. Peptides,18(7), 1009-1013. ↩︎
  10. Wessells, H., Fuciarelli, K., Hansen, J., Hadley, M. E., Hruby, V. J., Dorr, R., & Levine, N. (1998). Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. The Journal of urology, 160(2), 389-393. ↩︎

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