Category
Muscle & Anabolic
Anabolic peptides and growth factors studied for muscle accrual.
ACE-031
ACE-031 (Ramatercept) — Soluble Activin Receptor Type IIB Fc Fusion
Recombinant fusion protein combining the extracellular domain of activin receptor IIB with human IgG1 Fc. Phase 2 trials in Duchenne muscular dystrophy halted due to bleeding events. Development discontinued.
Apitegromab
Apitegromab (SRK-015)
Scholar Rock selective inhibitor of myostatin activation, Phase 3 SAPPHIRE in spinal muscular atrophy met primary endpoint; received FDA CRL.
Follistatin
Follistatin 344
Myostatin- and activin-binding protein investigated for muscle growth; sold as research peptide with no human RCT data.
Follistatin-315
Follistatin-315 (FS-315) — Soluble Follistatin Isoform
Soluble 315-amino-acid isoform of natural follistatin. Binds and neutralizes myostatin, activin A, and related TGF-beta superfamily ligands. WADA-prohibited.
IGF-1 DES
IGF-1 DES (1-3) IGF-1, des-amino IGF-1 truncated 67-amino-acid IGF-1 analog
Truncated 67-amino-acid IGF-1 missing the N-terminal Gly-Pro-Glu tripeptide. 5-10x higher IGF-1 receptor affinity than native IGF-1. Short half-life enables site-specific local effects. Research chemical, no FDA approval, WADA-banned.
IGF-1 LR3
IGF-1 LR3 (Long R3 IGF-1, 83-amino-acid IGF-1 analog with N-terminal extension and Arg3 substitution)
An 83-amino-acid modified IGF-1 with N-terminal 13-aa extension and Arg3 substitution. Reduced IGFBP binding produces 3x increased bioavailability. Half-life 20-30 hours versus 12-15 minutes for native IGF-1. Research chemical. WADA-banned.
MGF
MGF (Mechano Growth Factor, IGF-1Ec)
A splice variant of the IGF-1 gene expressed in muscle after mechanical loading. The 24-amino-acid E-peptide activates muscle satellite cells. No human clinical trials. Off-label use in bodybuilding.
PEG-MGF
PEG-MGF (Pegylated Mechano Growth Factor, pegylated IGF-1Ec C-terminal 24-aa E-peptide)
Pegylated 24-amino-acid C-terminal E-peptide of IGF-1Ec (mechano growth factor). Half-life extended from 5-7 minutes (native) to 24-72 hours via PEG conjugation. Research chemical with no published human clinical trials. WADA-banned.
Peptides for Muscle Growth
Peptides for muscle growth is a category covering compounds studied for skeletal muscle hypertrophy, strength, and recovery. The category attracts heavy user interest. The clinical-trial evidence in healthy adults is thin.
IGF-1 LR3 (Long R3 IGF-1) is a stabilized analog of insulin-like growth factor 1 with extended half-life. Studied for muscle protein synthesis, satellite-cell activation, tissue repair, and growth in young animal models. No human trial has tested IGF-1 LR3 for athletic muscle gain. Its primary use sits outside any regulatory framework.
Mechano growth factor (MGF) is an IGF-1 splice variant produced locally in response to mechanical loading. The mechanism is well characterized in animal models. Synthetic MGF as a research peptide has no completed human trial.
Follistatin-344 and Follistatin-315 are myostatin-binding proteins studied for muscle wasting and Duchenne muscular dystrophy. ACE-031 (a soluble activin receptor IIB) was developed for the same target and discontinued in Phase 2 after two epistaxis events.
Apitegromab is a Phase 3 anti-myostatin antibody in development for spinal muscular atrophy. The myostatin pathway is one of the most studied targets in this category. None of the muscle-pathway compounds has FDA approval for athletic or anti-aging use.
Doping flag. IGF-1 LR3, MGF, follistatin, and all myostatin pathway modulators are on the World Anti-Doping Agency prohibited list under section S2. Use in competitive sport is an anti-doping rule violation. Several have been the subject of athlete investigations.