Bremelanotide (PT-141)

• synthetic peptide analog of alpha-melanocyte stimulating hormone (α-MSH) that is currently being developed as a treatment for sexual dysfunction, specifically erectile dysfunction and sexual arousal disorder (cue a spike in my search traffic, hooray for sexy keywords!)
• α-MSH is a peptide hormone that acts via melanocortin receptors to do interesting things like turn you on and cause your skin to produce more melanin (pigment)
• has been shown to cause a rapid dose-dependent increase in erectile activity in dudes and increase sexual arousal in both the ladies and the gents
  
• derived from melanotan-II (MT-II), a cyclic lactam analog of α-MSH that is being developed as a sunless tanning agent (it was during studies with this compound as a tanning agent that it's ability to cause erections was discovered, much the same way that Viagra was discovered, leading to the development of bremelanotide)
  
• stimulates certain neurons in rat brain (specifically: hypothalamus) that are responsible for signaling erections (induces and facilitates erections) and increases activity in brain regions associated with sexual responses
• doesn't appear to affect the vasculature of the genitals (like Viagra and co.) but instead appears to act directly on brain to increase sexual desire
  

- Diamond LE et al. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist. J Sex Med. 2006 Jul;3(4):628-38.
- Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY. PT-141: a melanocortin agonist for the treatment of sexual dysfunction. Ann N Y Acad Sci. 2003 Jun;994:96-102.