MGF
Hormonal and Signaling
ABOUT
Mechano-growth factor (MGF) refers to an IGF-1 splice-variant concept. Human exercise studies measure MGF-related mRNA expression, while synthetic MGF-peptide findings are principally cell and animal research; one independent in-vitro replication study found no apparent effect on human or mouse myoblast proliferation or differentiation.
EVIDENCE OVERVIEW
Reasoned from mechanism, not measured in people
WHAT THIS MEANS
Theoretical. Review the research and limitations before relying on this record.
IDENTITY
HALF-LIFE
HOW IT IS THOUGHT TO WORK
Mechano growth factor is the IGF-1Ec splice variant produced locally in muscle after mechanical loading. It arises from alternative splicing that gives a different 3-prime exon and C-terminal sequence. Compared with liver-derived systemic IGF-1 it is not glycosylated, is smaller, has a shorter unbound half-life and different binding-protein and receptor affinities. It is credited with high potency for inducing local protein synthesis and preventing apoptosis.
PHARMACOKINETICS
The only pharmacokinetic statement in the literature is comparative and qualitative: a shorter half-life than systemic IGF-1 in the unbound state. No quantitative human value exists, and the endogenous peptide acts locally where it is produced, which is not the same exposure as an injected dose.
REVIEW
PUBLISHED PAIR RECORDS
with IGF-1 LR3
Overlapping IGF-1 pathway activityIGF-1 LR3 and MGF are both IGF-1-pathway analogues or splice variants, so their activity converges on IGF-1 receptor signalling rather than on separate mechanisms. Regulatory labelling for recombinant IGF-1 records insulin-like hypoglycaemic effects arising from IGF-1 receptor homology with the insulin receptor. No human study has characterised these specific research analogues in combination, so the size of any combined effect is uncharacterised rather than known to be small. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 19 Aug 2026with IGF-1 DES
Overlapping IGF-1 pathway activityIGF-1 DES and MGF are both IGF-1-pathway analogues or splice variants, so their activity converges on IGF-1 receptor signalling rather than on separate mechanisms. Regulatory labelling for recombinant IGF-1 records insulin-like hypoglycaemic effects arising from IGF-1 receptor homology with the insulin receptor. No human study has characterised these specific research analogues in combination, so the size of any combined effect is uncharacterised rather than known to be small. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 19 Aug 2026with peg-mgf
Overlapping IGF-1 pathway activityMGF and PEG-MGF are both IGF-1-pathway analogues or splice variants, so their activity converges on IGF-1 receptor signalling rather than on separate mechanisms. Regulatory labelling for recombinant IGF-1 records insulin-like hypoglycaemic effects arising from IGF-1 receptor homology with the insulin receptor. No human study has characterised these specific research analogues in combination, so the size of any combined effect is uncharacterised rather than known to be small. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 19 Aug 2026with follistatin-344
Converging on muscle growth from two different directionsFollistatin-344 antagonises myostatin and activin A, removing a brake on skeletal-muscle growth through the SMAD2/3 pathway. MGF pushes the accelerator instead, acting on IGF-1-receptor signalling. These are genuinely distinct pathways converging on the same tissue outcome, which is why the combination is attractive in principle and why its size cannot be predicted from either alone. The evidence does not support treating it as characterised: human follistatin data comes from AAV-delivered gene therapy in open-label muscular-dystrophy trials of a handful of patients, not from injected follistatin protein, and a case series reported central serous chorioretinopathy in bodybuilders using subcutaneous FS-344. Growth factors affecting muscle regeneration are prohibited at all times in sport. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026HUMAN EVIDENCE
No human clinical trial of MGF or its E-domain peptide has been conducted; human studies measure MGF-related mRNA expression after exercise rather than testing an administered peptide. Animal work shows motoneuron survival benefits over IGF-1 in mice. The most important result is an independent replication attempt that failed: the synthetic MGF peptide had no apparent effect on myoblasts or primary muscle stem cells, human or mouse. Trials of IGF-1 itself in ALS produced conflicting results, and none of that evidence is about MGF.
REPORTED EFFECTS
No human safety data exists. Growth factors affecting muscle regeneration are prohibited at all times in sport. No regulator has approved this substance for the use described here, so there is no label-verified dose, purity standard, or safety monitoring requirement behind it.
RESEARCH LIMITATIONS
Endogenous transcript observations do not validate a manufactured MGF peptide as a treatment. There is no curated clinical efficacy or safety profile for the marketed peptide products represented by this record.
CURATED SOURCES · 4