The melanocortins (MCs) are a family of multifunctional peptidergic hormones. Several superpotent, prolonged acting, enzymatically resistant, MC analogs have been designed and synthesized to help clarify the nature and role of MCs and their receptors (MCRs) in physiological functions. Two of these analogs, a linear peptide, melanotan I, and a cyclic truncated peptide, melanotan II (MTI and MTII, respectively) have been patented and tested clinically for studies on tanning of the skin (MTI) and for diagnosis and treatment of male erectile dysfunction (MTII).The effects of melanotan-II, a non-specific agonist of melanocortin receptors, on erection and its possible sites of action were investigated in anesthetized rats. Erectile events were of higher amplitude in rats treated with melanotan-II i.t. (0.2 microg) delivered at the L6-S1 level than in animals treated with the vehicle i.t. delivered. Erectile responses elicited by cavernous nerve stimulation were increased after i.v. melanotan-II (1 mg/kg), thereby exerting facilitator effect on erection. These results lead to the conclusion that central and peripheral melanocortin pathways are recruited by melanotan-II, depending on its route of delivery, to exert both inducer and facilitator activities on erection. Melanotan II (MTII), can enhance sexual function in human males (erectile activity) and females (increased levels of sexual desire and genital arousal). Unlike other sexual-enhancement drugs, MTII works at the level of the brain, thus eliciting a rather natural sexual response with minimal or no undesirable side effects. The actions of the peptide were discovered accidentally while studying the effects of the peptide and related analogs on human skin pigmentation (tanning). Effective dosages were shown to be 0.02mg - 0.03mg per kilogram(2.2 pounds) of body weight. Adverse effects such as nausea, lethargy, and priapism were experienced by some who used a dosage higher than 0.03mg/kg. Effective cycle duration for tanning was shown to vary between skin types. Using the Fitzpatrick Skin Type Scale effective cycle length for type I, II, and III. No notable effects were shown for those with skin types IV or greater. Type I showed best results with a cycle duration of 15-18 subcutaneous injections, one per day, at desired concentration. Type II showed best results with a cycle duration of 12-15 subcutaneous injections, one per day, at target concentration. Finally, type III skin showed best results with a cycle duration of 9-12 subcutaneous injections, one per day, at target concentration. Melanotan II does degrade quickly at room temperature so unused powder should always be stored in the freezer and once constituted any unused portions need to be refrigerated and used fairly quickly there after. Bibliography: Giuliano F, Clement P, Droupy S, Alexandre L, Bernabe J. 2006. Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat Neuroscience.138(1):293-301. Epub 2005 Dec 19. Hadley ME. 2005. Discovery that a melanocortin regulates sexual functions in male and female humans. Peptides. Oct;26(10):1687-9. Hadley ME, Dorr RT. 2006. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides. Apr;27(4):921-30. Lam CW, Perretti M, Getting SJ. 2006. Melanocortin receptor signaling in RAW264.7 macrophage cell line. Peptides. Feb;27(2):404-12. Epub 2005 Nov 15. Menyhert J, Wittmann G, Hrabovszky E, Keller E, Liposits Z, Fekete C. 2006. Interconnection between orexigenic neuropeptide Y- and anorexigenic alpha-melanocyte stimulating hormone-synthesizing neuronal systems of the human hypothalamus. Brain Res. Mar 3;1076(1):101-5. Epub 2006 Feb 13. Pfaus, James G. , Annette Shadiack, Tanya Van Soest, Maric Tse, and Perry Molinoff. 2004. Selective facilitation of sexual solicitation female rat by a melanocortin receptor agonist. PNAS. July 6(101): 10201-10204 Silva AA, Kuo JJ, Tallam LS, Liu J, Hall JE. 2006. Does obesity induce resistance to the long-term cardiovascular and metabolic actions of melanocortin 3/4 receptor activation? Hypertension. 2006 Feb;47(2):259-64. Epub 2005 Dec 27. Melatonin.org Made In the USA According to USP guidelines!! Cutting Edge Labs Melanotan II reaches purity of 98.7%(HPLC). Shipped in pharmaceutical temperature control packaging.