The human IGF-1 gene can be spliced into more than one protein product. IGF-1Ea is the systemic form, produced mainly in the liver and released into circulation — this is the basis for both native IGF-1 and the engineered IGF-1 LR3 analog discussed throughout this site. IGF-1Ec, by contrast, is expressed locally in tissues, including skeletal muscle, and is commonly known by its research nickname: mechano growth factor, or MGF.
Because both trace back to the same parent gene, they are sometimes discussed together in general peptide conversation — but the biology from that point forward diverges considerably.
IGF-1 (and its LR3 analog) acts systemically: it circulates in the bloodstream and can, in principle, reach IGF-1 receptors throughout the body, subject to the IGF-binding-protein regulation discussed elsewhere on this site. MGF, in contrast, is documented in the literature as acting locally — produced and active largely within the tissue that generates it, particularly in response to mechanical loading, which is the origin of its "mechano" name.
This local-versus-systemic distinction is the core reason the two are studied as separate research questions rather than interchangeable growth factors, even though both ultimately connect to IGF-1 receptor biology.
MGF has a distinct C-terminal peptide sequence not shared with IGF-1Ea, a structural difference arising from the alternative gene splicing itself rather than any laboratory engineering. IGF-1 LR3, by contrast, is a deliberately engineered N-terminal modification of the IGF-1Ea sequence, designed specifically to reduce IGF-binding-protein affinity — an entirely different kind of structural change, targeting a different research problem.
Synthetic MGF fragments used in research are themselves separate laboratory constructs, distinct from IGF-1 LR3 despite the shared gene ancestry.
IGF-1 LR3, as covered extensively elsewhere on this site, is used where researchers need sustained systemic-style IGF-1 receptor engagement — for example, in extended cell-proliferation assays. MGF research, by comparison, has generally focused on tissue response to mechanical loading, particularly in muscle biology, as a locally-acting signal distinct from systemic growth-factor exposure.
Neither compound is an approved human or veterinary therapeutic. Both exist in the research literature purely as tools for studying different aspects of IGF-1-related biology.
This comparison is published as general research information only. Neither IGF-1 LR3 nor MGF is part of REVIVE LAB UAE's catalog, and this article contains no dosing, administration, or protocol guidance for either compound.
Researchers with genuine interest in either compound should consult the primary scientific literature and their own institution's research-chemical sourcing and safety protocols rather than general web content.