Description
MGF (Mechano Growth Factor) is a splice variant of the IGF-1 gene that is specifically expressed in mechanically stressed skeletal muscle tissue. Structurally, MGF is the product of an alternative splice reaction of the IGF-1 precursor (IGF-1Ec in humans), which contains an E-domain peptide absent in classical IGF-1. This E-domain is considered central to the distinct activity of MGF.
The research mechanism differs from standard IGF-1: while IGF-1 primarily addresses long-term hypertrophy and differentiation, MGF in preclinical studies is associated with acute activation of satellite cells (muscular stem cells) and the early repair cascade after mechanical stress. This characteristic makes MGF a distinct research tool within the IGF-1 family.
The E-domain itself shows independent activity in research models, independent of the IGF-1 receptor. The exact molecular targets of the E-domain are still under characterization in research literature.
The half-life of MGF is very short (in the range of a few minutes), making the compound a tool for locally limited research applications. For longer duration of action, the PEGylated variant PEG-MGF exists.
In research setups, MGF is typically applied locally after a mechanical loading phase to enable repair cascade studies.
MGF is available in 2mg vials as 10-vial packs.
This information is for research and educational purposes only. No medical recommendations.
Risks & Safety
MGF is considered well tolerated per study reports. As a locally acting IGF-1 splice variant with a very short half-life, systemic exposure is low, which keeps the profile mild.
Observed in research and user reports:
- Injection site: mild redness, pressure or transient irritation at the injection site is the most common observation with local subcutaneous use.
- Very short half-life: MGF is degraded within a few minutes, requiring frequent application intervals - the low systemic exposure also limits observations.
- Anabolic pathway activation: because MGF triggers proliferative repair cascades in studies, the literature discusses a theoretical concern that existing abnormal tissue could also be co-stimulated. No evidence supports this.
- Occasionally brief fatigue or a mild feeling of warmth shortly after application is reported.
- No long-term data: robust long-term human studies do not exist. The molecular targets of the E-domain are still under characterization in research literature.
This classification does not replace medical advice. Risk and responsibility for any actual use lie entirely with the buyer.
Studies
- Different roles of the IGF-I Ec peptide (MGF) and mature IGF-I in myoblast proliferation and differentiation - FEBS Letters 2002: Cell study: the E domain of MGF increased myoblast proliferation and inhibited terminal differentiation, unlike mature IGF-I and apparently via a different receptor.
- Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage - Journal of Physiology 2003: After local muscle damage in rats, MGF mRNA was expressed rapidly and only for a few days, in parallel with markers of satellite cell activation, while IGF-IEa followed with a delay.
- Expression of IGF-I splice variants in young and old human skeletal muscle after high resistance exercise - Journal of Physiology 2003: After high-resistance exercise, MGF mRNA rose in the muscle of young but not elderly subjects, while IGF-IEa was unchanged in both groups.
- Minireview: Mechano-growth factor: a putative product of IGF-I gene expression involved in tissue repair and regeneration - Endocrinology 2010: Critical minireview: distinguishes the IGF-I splice variant from the synthetic 24-amino-acid MGF peptide and notes that no corresponding natural peptide has so far been identified in cells or tissues.
- Mechano-growth factor peptide, the COOH terminus of unprocessed insulin-like growth factor 1, has no apparent effect on myoblasts or primary muscle stem cells - American Journal of Physiology - Endocrinology and Metabolism 2014: Replication attempt by two pharmaceutical labs: the MGF peptide neither increased proliferation of myoblasts or muscle stem cells nor inhibited their differentiation, calling the physiological role of MGF into question.
