Myostatin-derived peptide fragment
Myostatin-7
Cited range Preclinical
What it is
Myostatin-7 is a heptapeptide corresponding to a region of the myostatin prodomain. It is sometimes called the “myostatin propeptide fragment.” The concept is that a small fragment of the propeptide can bind mature myostatin and reduce its activity, a different strategy from blocking the receptor.
Benefits in plain language
What researchers and reference users usually mean when they talk about this compound. These are study themes and common claims — not a promise that it will do this in you.
- The pitch is a lighter, injectable take on myostatin inhibition — the same general idea as ACE-031 but with a small peptide.
- Seen in research discussions about muscle hypertrophy without receptor-level blockade.
- Most of the supporting work is rodent, and the studies are sparse even there.
- It is often confused with follistatin-344, which acts on the same pathway by a different mechanism.
If a branded, FDA-approved product exists, that label is the only dose that is actually authorized. Research-chemical vials are a different object.
Mechanism of action
Latent myostatin is held inactive by its prodomain. Peptide fragments from that prodomain can associate with mature myostatin and interfere with receptor binding, reducing SMAD2/3 signaling in muscle. Whether the specific seven-residue fragment achieves this reliably in vivo, at achievable exposure, is not well established.
Possible side effects / caveats
No human safety data are published. Theoretical concerns mirror other myostatin-pathway interventions: effects on tendon and connective tissue, vascular changes seen with receptor-level blockade, and the unknown consequences of chronic pathway suppression. Purity and identity of research material are frequent problems with short fragments.
Protocol ranges
| Source tier | Amount | Frequency / duration | Notes |
|---|---|---|---|
| Cited range | Approximately 100–500 mcg/day | Daily, cycled in community references | Forum-derived; no dose-finding study |
| Preclinical papers | mcg/kg to mg/kg | Model-dependent | Rodent exposures; not directly transferable |