Peptide Database
265 therapeutic peptides with research summaries, clinical findings, and regulatory status.
Melanotan II
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 (Long-Arg3)
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)
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.
MGF (Mechano Growth Factor)
Mechano Growth Factor is a splice variant of the IGF-1 gene expressed in response to mechanical stress on muscle tissue. The peptide contains a unique C-terminal domain resulting from alternative splicing that distinguishes it from systemic IGF-1. MGF is proposed to act locally in skeletal muscle to activate satellite cells and promote muscle fiber repair and hypertrophy following mechanical loading or injury.
PEG-MGF
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.
Follistatin-344
Follistatin-344 is a 344-amino acid glycoprotein that functions as a binding protein and endogenous antagonist of myostatin and other members of the TGF-beta superfamily. By sequestering myostatin, follistatin removes inhibitory signals that limit skeletal muscle growth, thereby permitting increased muscle fiber hypertrophy and hyperplasia. The peptide also modulates activin and bone morphogenetic protein signaling pathways.
ACE-031 (Ramatercept)
ACE-031 is a recombinant fusion protein combining the extracellular domain of the activin receptor type IIB with a human IgG1 Fc domain. This soluble receptor acts as a decoy to bind and neutralize myostatin, activin, and other negative regulators of muscle growth. By inhibiting these TGF-beta superfamily ligands, ACE-031 was designed to promote muscle hypertrophy in conditions characterized by muscle wasting.