Research Comparison

IGF-1 LR3 vs PEG-MGF

In Short

IGF-1 LR3 is igfbp-resistant long-acting igf-1 analog (n-terminal 13-aa extension + arg3 substitution); PEG-MGF is igf-1 splice variant / mechano growth factor (e-domain peptide); pegylated analog. Both are supplied as lyophilized powders for laboratory and in-vitro research use only. The table below compares their molecular data, half-life and research focus side by side.

	IGF-1 LR3	PEG-MGF
Classification	IGFBP-resistant long-acting IGF-1 analog (N-terminal 13-aa extension + Arg3 substitution)	IGF-1 splice variant / mechano growth factor (E-domain peptide); pegylated analog
Molecular formula	—	—
Molecular weight	9117.5 g/mol	—
CAS number	946870-92-4	—
Research half-life	Substantially longer than native IGF-1 (whose circulating free half-life is only minutes) because of greatly reduced IGFBP binding; commonly cited as on the order of ~20-30 hours, but this figure is approximate and not rigorously established for humans.	Native MGF E-peptide is very short-lived (minutes) in solution; PEGylation is intended to extend solution stability. Precise pegylated half-life is not well characterized in peer-reviewed literature.
Primary research focus	Cell proliferation and hyperplasia studies	Muscle satellite cell activation research
Form	Lyophilized powder	Lyophilized powder
Price from	$89.99	$48.62

IGF-1 LR3

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified 83-amino acid analogue of human IGF-1 in which glutamic acid at position 3 is replaced with arginine, and a 13-amino acid N-terminal extension peptide is added. These modifications significantly reduce binding to IGF-binding proteins (IGFBPs), resulting in a much higher proportion of free, bioactive peptide in circulation compared to native IGF-1. The mechanism of action involves binding to the IGF-1 receptor (IGF-1R), a tyrosine kinase receptor that activates the PI3K/Akt and MAPK/ERK signaling cascades to promote cell proliferation, differentiation, and survival. Research demonstrates that IGF-1 LR3 has approximately 2-3 times the potency of native IGF-1 in cell culture proliferation assays due to its reduced IGFBP sequestration (Francis et al., Journal of Molecular Endocrinology, 1992). In muscle biology research, IGF-1 signaling promotes satellite cell activation and myofiber hypertrophy while simultaneously inhibiting myostatin-mediated atrophy pathways. Studies also indicate IGF-1 LR3 promotes both hyperplasia (new cell formation) and hypertrophy (cell enlargement), distinguishing it from GH secretagogues that primarily drive hypertrophy. Compared to native IGF-1, LR3 has a significantly extended half-life of approximately 20-30 hours versus 12-15 minutes, making it substantially more practical for research applications. Store lyophilized powder at -20C; reconstitute with 0.1M acetic acid or bacteriostatic water and refrigerate at 2-8C, using reconstituted material within 30 days. IGF-1 LR3 is studied by cell biology laboratories, muscle physiology researchers, cancer biology departments investigating IGF-1R signaling, and metabolic research institutions.

Full IGF-1 LR3 research guide

PEG-MGF

PEG-MGF (pegylated mechano growth factor) is a stabilized analog of the MGF peptide, a splice variant of insulin-like growth factor-1 produced by mechanically stressed muscle tissue. The native MGF E-domain peptide is thought to play a role in activating muscle satellite (stem) cells and initiating repair following exercise-induced damage. PEGylation extends the molecule's half-life in solution, making it a more practical tool for research into muscle regeneration, hypertrophy signaling, and local tissue repair pathways. Supplied as a lyophilized powder for in-vitro and laboratory research use only.

Full PEG-MGF research guide

Frequently Asked Questions

What is the main difference between IGF-1 LR3 and PEG-MGF?

IGF-1 LR3 is classified as igfbp-resistant long-acting igf-1 analog (n-terminal 13-aa extension + arg3 substitution), while PEG-MGF is igf-1 splice variant / mechano growth factor (e-domain peptide); pegylated analog. They are distinct research compounds with different mechanisms — the comparison table above sets out the molecular and pharmacokinetic differences side by side.

Can IGF-1 LR3 and PEG-MGF be studied together?

Some research protocols evaluate related peptides in combination, and research blends exist. Combination study design depends entirely on the research question and model. Both compounds are supplied for laboratory and in-vitro research use only — not for human use.

Are IGF-1 LR3 and PEG-MGF legal to buy for research?

Both are sold in the United States as research chemicals for laboratory and in-vitro use only. Neither is FDA-approved for human use. Researchers are responsible for compliance with all applicable regulations.

Buy IGF-1 LR3

From $89.99 — ≥98% HPLC, COA included.

Buy PEG-MGF

From $48.62 — ≥98% HPLC, COA included.

Research Use Only. This comparison summarizes published research. It is not medical advice. Neither compound is for human consumption or FDA-approved.