No One Knew What a Peptide Was 5 Years AgoNow They're Everywhere. But What Exactly Is a Peptide? Imagine just wanting to be jacked and tan and you end up like this? Melanotan II is a peptide that increases the melanin in your skin and can give men a boner that Should You Try Peptide Stacking? Henry Ford Health Detroit, MI Melanotan II reverses memory impairment induced by a short term HF diet ScienceDirect