MGF (Mechano Growth Factor)

A synthetic cyclic analog of alpha-melanocyte stimulating hormone (alpha-MSH) that non-selectively activates melanocortin receptors MC1R through MC5R. Melanotan II stimulates melanogenesis for skin tanning via MC1R, modulates sexual arousal through MC3R/MC4R in the hypothalamus, and reduces appetite through central MC4R activation. It is not FDA-approved and carries significant safety concerns.

IGF-1 LR3 is a synthetic analogue of insulin-like growth factor 1 with an N-terminal extension of 13 amino acids and a substitution of arginine for glutamic acid at position 3. These modifications reduce binding to IGF-binding proteins, resulting in an extended half-life and increased bioavailability compared to native IGF-1. The peptide promotes anabolic processes including muscle protein synthesis, glucose uptake, and cellular proliferation. IGF-1 LR3 is not approved for human use and is primarily available as a research reagent, though it is sometimes misused in athletic and bodybuilding contexts.

IGF-1 DES (1-3) is a truncated analogue of insulin-like growth factor 1 lacking the first three N-terminal amino acids (glycine-proline-glutamate). This structural modification prevents binding to IGF binding proteins in serum, resulting in a shorter half-life but significantly increased potency at the IGF-1 receptor compared to native IGF-1. The peptide is hypothesized to promote localized muscle hypertrophy and tissue repair through enhanced receptor activation in target tissues.

PEG-MGF is a pegylated derivative of Mechano Growth Factor designed to extend systemic half-life through the addition of polyethylene glycol moieties. Pegylation reduces renal clearance and proteolytic degradation, theoretically allowing for less frequent dosing and broader tissue distribution compared to unmodified MGF. The modified peptide retains the proposed satellite cell activation properties of native MGF.