The growth-factor peptides studied for muscle mass, the myostatin "brake", and fat metabolism — grounded in muscle-wasting research. Every claim is sourced on each peptide's guide.
Muscle research runs on two levers. The first is growth-factor signaling: IGF-1 drives the build-and-repair response in muscle tissue. The second is the myostatin pathway — myostatin is the body's built-in brake on muscle growth, and follistatin is what blocks it. AOD-9604 approaches body composition from the other side, as a fragment of growth hormone studied for fat metabolism without GH's growth effects.
The clinical motivation here is muscle-wasting — muscular dystrophy, sarcopenia, and cachexia, where losing muscle is the danger. That framing matters, because the enhancement market has run far ahead of the evidence: none of these is approved for muscle growth, and much of the foundational work is in animals.
Myostatin-blocking protein studied for pronounced muscle-growth effects in animal research.
Growth-factor mediator studied for muscle repair and growth; approved only for a rare pediatric deficiency.
Inhibitors of the myostatin muscle brake, studied for muscle-wasting conditions.
Growth-hormone fragment studied for fat metabolism; early human trials did not match the animal results.
Follistatin has the deepest research base — its gene and protein studies produced some of the most dramatic muscle-growth results on record, including in primates. Myostatin inhibitors tell the same story in reverse: removing the brake produced double-muscled animals, but human translation is early. IGF-1 is the most clinically established — one engineered form is approved for a rare pediatric growth deficiency — while broader use remains research-stage.
AOD-9604 is the honesty check of this pillar: early human obesity trials did not reproduce its animal fat-loss results — a useful reminder that preclinical promise often thins out in people. Treat everything here as research findings about muscle biology, not as proven enhancement.
The most-used peptide combinations, what the research actually says, and where to buy — one page, one email.
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