MGF: Scientific Profile

Publicado el 12 de julio de 2026 · Actualizado el 17 de julio de 2026

MGF (Mechano Growth Factor) is a splice variant of the IGF-1 gene (IGF-1Ec) whose carboxy-terminal E domain acts as a distinct signaling peptide, studied in research for its role in satellite cell activation and the response of skeletal muscle to mechanical damage. Reference peptide compound for research use; without an unequivocally assigned CAS. Its proposed mechanism is the mobilization of myogenic precursors, in parallel to the classic IGF-1 pathway.

MGF (Mechano Growth Factor) is the common name of an alternative splice isoform of the insulin-like growth factor 1 (IGF-1) gene, formally designated IGF-1Ec in humans (and IGF-1Eb in rodents). The IGF-1 gene can be transcribed and processed in different ways; one of those variants retains an exon that introduces a reading-frame shift at the carboxy-terminal end, generating an E domain (E peptide) with a unique sequence that does not appear in the classic systemic IGF-1 isoform. This E peptide, together with the mature portion of IGF-1, constitutes the molecule that the research literature calls MGF. In experimental work, "MGF" usually refers specifically to the synthetic fragment corresponding to the carboxy-terminal E peptide, rather than to the complete protein, which is a frequent source of confusion about its exact molecular identity.

From a structural standpoint, MGF is a single-chain peptide. Unlike well-characterized peptide compounds with defined CAS, molecular formula, and molecular weight, MGF lacks a unique CAS identifier and is often marketed as a fragment of the E domain; for this reason, in this record the molecular formula and molecular weight are kept as not available, and the amino acid sequence is not asserted as definitive. The name "IGF-1Ec" reflects its origin as a splice variant of the IGF-1 locus, and should not be interpreted as meaning that MGF is identical in activity to the mature circulating IGF-1. The category "gh-secretagogues" is approximate: MGF is not a growth hormone secretagogue in the strict sense (it does not stimulate the pituitary), but rather a local factor related to the GH/IGF-1 axis at the tissue level.

The proposed mechanism of action for MGF centers on the response of skeletal muscle to mechanical stress and to damage. The preclinical and cell culture studies historically associated with the group of Geoffrey Goldspink described that the expression of the MGF variant increases transiently in muscle after resistance exercise or injury, preceding the expression of the systemic isoform of IGF-1. The dominant hypothesis is that the E peptide of MGF acts as a signal distinct from the canonical IGF-1 receptor (IGF-1R) pathway: it would favor the activation and proliferation of satellite cells (the quiescent myogenic precursors of muscle), delaying their terminal differentiation and thus expanding the reservoir of nuclei available for the repair and growth of the muscle fiber. It has been proposed that the E peptide exerts part of its effects through a mechanism independent of or only partially dependent on the IGF-1R, possibly through membrane interactions not yet fully characterized, which would explain why its signaling profile differs from that of mature IGF-1. Effects on neuronal and cardiac tissue have also been explored in models, where MGF has been studied in contexts of protection against ischemic or excitotoxic stress.

The documented research applications for MGF are concentrated in skeletal muscle biology: models of muscle hypertrophy and regeneration, study of satellite cell dynamics, and responses to damage from exercise or injury. Outside of muscle, there are lines of preclinical research on neuroprotection (models of neuronal damage and hypoxia) and on the heart (models of infarction and remodeling). It is important to emphasize that most of this evidence comes from studies in animals, cell cultures and specific research groups; the translation of these findings to a validated clinical use is not established.

The level of evidence for MGF must be described honestly as preclinical and limited. There is no approved drug based on MGF, and much of the body of literature on the E peptide derives from a limited number of laboratories. Practical issues relevant to research —such as the stability of the peptide in plasma, its very short half-life, the ambiguity over whether the material corresponds to the E domain or to the complete molecule, and the variability between synthetic batches— mean that conclusions must be taken with caution. For this reason there also exist pegylated variants (PEG-MGF) designed to prolong stability, which constitute distinct compounds with their own considerations.

In summary, MGF is a research peptide derived from a splice variant of IGF-1, whose scientific interest lies in its proposed role as a local signal for muscle repair through the activation of satellite cells. Its exact molecular identity as a research product is less standardized than that of peptides with defined CAS and formula, and its evidence base is fundamentally preclinical.