What the studies show
No human study of any design has given MGF or PEG-MGF. Claims rest on rodent injections and on human studies that only measured natural MGF expression.
Animal studies, cell studies, or anecdotes only. This is where almost every viral peptide sits. Promising and proven are different words for a reason.
- 1Hameed M, Lange KH, Andersen JL, et al. The effect of recombinant human growth hormone and resistance training on IGF-I mRNA expression in the muscles of elderly men.J Physiol, 2004Measures natural MGF expression; nothing administered.
- 2Searches of PubMed and trial registries for administered mechano growth factor or PEG-MGF in humans.LYO literature search, September 2026No human administration study identified.
In context
Mechano growth factor is a splice variant of IGF-1 that muscle makes briefly after loading or damage; its distinctive tail is thought to signal muscle stem cells to divide. PEG-MGF is a synthetic version of that tail with polyethylene glycol attached to make it last longer, sold for muscle repair and growth. No human study has ever administered it: the entire human literature measures how much MGF muscle expresses after exercise, growth hormone or ultrasound. It is not approved anywhere and is named on the Prohibited List.
PEG-MGF is not approved; research reagent. Legal status differs by country — see the regulation section or the jurisdiction pages.
Questions
Is PEG-MGF proven to help with muscle growth or repair?
What studies are behind the grade?
Is PEG-MGF approved for this?
Other outcomes for PEG-MGF
- DMGF expression after exercise (the body's own)Several small physiology studies
- DSafety in humansadverseNone
Written and maintained by LYO Research — how pages are written and checked. Reviewed 10 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →