Comparison

Ipamorelin vs MGF

Function

While Ipamorelin is investigated for producing moderate, physiologic-like GH pulses useful for studying anabolic, body-composition, and recovery effects with a relatively clean endocrine side-effect profile compared with earlier GHRPs16, MGF is upregulated in muscle after mechanical overload, where it supports tissue repair and growth; recombinant forms are studied for regenerative and performance-enhancement effects22138.

Mechanism

While Ipamorelin works as a third-generation pentapeptide growth hormone secretagogue that selectively agonizes the ghrelin (GHSR-1a) receptor to trigger controlled, GH-specific pituitary release with minimal effects on cortisol or prolactin16269596, MGF is a 24-amino-acid E-peptide splice variant of IGF-1 (IGF-1Ec) produced in mechanically stressed or damaged muscle that activates IGF1R and local anabolic pathways involved in muscle repair and hypertrophy22138144.

Length and Sequence

Ipamorelin is 5 amino acids long, whereas MGF is longer as it has a length of 24 amino acids. Ipamorelin is made up of a sequence of Aib, Histidine, D-2-Nal, Phenylalanine, Lysine. MGF is made up of a sequence of Tyrosine, Glutamine, Proline, Proline, Serine, Threonine, Asparagine, Lysine, Asparagine, Threonine, Lysine, Serine, Glutamine, Arginine, Arginine, Lysine, Glycine, Serine, Threonine, Phenylalanine, Glutamic acid, Glutamic acid, Arginine, Lysine.

Receptor

Ipamorelin

Ghrelin/growth hormone secretagogue receptor type 1a (GHSR-1a)169596104

MGF

Insulin-like growth factor 1 receptor (IGF1R) 134139

Organism or Origin

Ipamorelin

Fully synthetic peptide ghrelin mimetic16

MGF

Endogenous human IGF-1 splice variant (IGF-1Ec) 2213897

Gene

Ipamorelin

GHSR

MGF

IGF1

Sources

16Ipamorelin peptide: A gentle pulse, but is it strong enough?, https://oathpeptides.com/2025/11/05/ipamorelin-peptide-a-gentle-pulse-but-is-it-strong-enough/
96Growth Hormone Secretagogue Receptor - ScienceDirect.com, https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/growth-hormone-secretagogue-receptor
22Mechano growth factor - Wikipedia, https://en.wikipedia.org/wiki/Mechano_growth_factor
97IGF1 Gene - Insulin Like Growth Factor 1, https://www.genecards.org/cgi-bin/carddisp.pl?gene=IGF1
134Insulin-like growth factor 1 receptor - Wikipedia, https://en.wikipedia.org/wiki/Insulin-like_growth_factor_1_receptor
138A Splice Variant of IGF-1 within the Growth Plate | PLOS One, https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0076133
139IGF1 receptor signaling pathways, https://pubmed.ncbi.nlm.nih.gov/29535161/
144Insulin-like growth factor 1 - Wikipedia, https://en.wikipedia.org/wiki/Insulin-like_growth_factor_1