MGF
Also known as: mechano growth factor, IGF-1Ec
Status
No approved product. No FDA-approved labeling exists, and no approval elsewhere is listed in this entry's sources. It is sold labelled as a research-use-only chemical; that label is not an approval for human use, and it does not mean any regulator has checked the identity, purity or content of the product.
What it is
The mechano growth factor splice variant of IGF-1, described in laboratory work as short-lived in its unmodified form.
What published research measured
The 24-amino-acid C-terminal E-peptide produced when the IGF-1 gene is alternatively spliced under mechanical load, first cloned by Yang and colleagues in 1996 and also called IGF-1Ec. Human muscle biopsy work (Philippou and colleagues) shows MGF messenger RNA rises sharply and briefly after exercise-induced muscle damage, then falls as the other IGF-1 isoforms rise — that much is well established about the body's own splice variant. What is contested is whether giving the synthetic peptide from outside does anything. Cell-culture studies on primary human muscle reported that the 24aa E-peptide extended the proliferative lifespan of satellite cells and delayed their senescence, though notably not in cells taken from older adults (Kandalla 2011), and that it raised progenitor cell numbers in healthy, dystrophic and ALS muscle (Ates 2007). Against that, an independent laboratory publishing in the American Journal of Physiology in 2013 found the same peptide had no apparent effect on myoblasts or primary muscle stem cells at all — a direct replication failure that the field has not resolved. No randomized controlled trial of exogenous MGF in humans has been completed. Unmodified MGF is described in laboratory work as short-lived, which is the stated reason the pegylated form is sold separately; its half-life in people has not been established. Prohibited at all times in sport under WADA class S2.
Source
Yang et al. 1996, original cloning of the IGF-1Ec splice variant · Ates et al. 2007, Journal of the Neurological Sciences — MGF E peptide and progenitor cells in ALS, dystrophic and normal muscle · Kandalla et al. 2011, Mechanisms of Ageing and Development — MGF-24aa-E peptide and human muscle progenitor cells across ages · Philippou et al. 2009, In Vivo — IGF-1 isoform expression after exercise-induced muscle damage in humans · Fornaro et al. 2013, American Journal of Physiology: Endocrinology and Metabolism — MGF peptide had no apparent effect on myoblasts or primary muscle stem cells (replication failure) · Goldspink 2005, British Journal of Sports Medicine — MGF, training and doping potential · WADA Prohibited List, class S2
Sources
No linked primary source is on file for this entry yet.
Educational use only, never medical advice. No doses.