MGF (Mechano Growth Factor)

MGF is the name given to a splice variant of the IGF-1 gene (IGF-1Ec in humans, IGF-1Eb in rodents) that muscle switches on after loading or damage. The "MGF" sold as a peptide is usually a synthetic 24-amino-acid copy of that variant's unique tail end (the E-domain, sequence YQPPSTNKNTKSQRRKGSTFEEHK), often with a modified C-terminus. It got famous through early lab work from Geoffrey Goldspink's group suggesting it kicks muscle stem cells into action. The honest picture is messier: a careful 2014 pharma replication found no effect on muscle cells at all, nobody has shown the free peptide actually exists in the body, and there are zero human trials.

The idea goes like this. When muscle is stretched or injured, the IGF-1 gene is spliced differently, producing a version with a different C-terminal E-domain. Researchers proposed that this E-domain gets cut off and acts on its own, pushing satellite cells (muscle stem cells) to multiply before mature IGF-1 tells them to fuse and build new fibers. Several studies reported that the E-peptide works without the classic IGF-1 receptor, and in heart cells it was reported to enter the cell, travel to the nucleus, and block the mitochondrial apoptosis pathway. The problem is that nobody has identified MGF's receptor, a 2010 Endocrinology review pointed out that no matching peptide has ever been isolated from cells, tissue or blood, and a 2014 study from Novartis and another drug company could not reproduce the core muscle-cell effects. So the mechanism is a hypothesis built on synthetic-peptide experiments, not established biology.

No, MGF (Mechano Growth Factor) is not currently FDA approved. Current status: Not FDA approved for any use, and not approved by any other regulator we could find. On FDA's 503A bulk substances list (updated May 14, 2026), "Mechano growth factor (MGF)" sits in Category 3, meaning it was nominated for compounding without adequate supporting information, so it is not on the list of substances pharmacies may compound from. No registered clinical trials found on ClinicalTrials.gov. WADA: prohibited at all times under S2.3 (Growth factors and growth factor modulators), which names "Mechano growth factors (MGFs)" explicitly on the 2026 List. Anti-doping labs have already found amidated MGF analogues in black-market products.

Prohibited at all times under WADA S2 (growth factors), where mechano growth factors (MGFs) are named.

Reported side effects include: No human safety data exists, Injection site reactions (expected with any injected peptide), Theoretical growth-promoting risk: MGF E-peptide stimulated prostate cancer cell growth in the lab, Unknown long-term effects, Product identity is uncertain: black-market MGF has been found as modified analogues. Individual responses vary based on dosage, duration, and personal health factors.

Community-reported common dose: No established human dose (Not established). Range: No published human dosing data. Administration: Local injection or infusion into tissue in animal studies; research-market products are injected. Community-reported doses. Not medical advice. Consult healthcare provider.