Body Composition Research Guide

IGF-1 LR3: Dosage, Benefits & Research Guide

Key Facts

IGF-1 LR3 is a body composition research peptide. Extended-activity IGF-1 analogue for cell proliferation and tissue repair research. It is supplied as a lyophilized powder for laboratory and in-vitro research use only — not for human consumption.

Classification	Extended-activity IGF-1 analogue for cell proliferation and tissue repair research.
Molecular Weight	9117.5 g/mol
CAS Number	946870-92-4
Research Half-Life	Not established in published literature
Form	Lyophilized powder
Research Category	Body Composition

What is 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.

IGF-1 LR3 Research Applications

In published and preclinical research, IGF-1 LR3 has been studied across the following areas:

Cell proliferation and hyperplasia studies
Metabolic function and diabetes research
Muscle preservation and myostatin inhibition
Longevity and anti-aging research

IGF-1 LR3 in Research: Reconstitution & Study Concentrations

IGF-1 LR3 is supplied as a lyophilized powder. For laboratory research it is reconstituted with bacteriostatic or sterile water; the solvent volume sets the working concentration. Published studies select concentrations specific to the assay or model system — there is no human dose, as IGF-1 LR3 is not approved for human use. Researchers should reference the primary literature for the model in question and document the exact lot COA.

Worked example: a 1mg vial reconstituted with 2 mL of bacteriostatic water yields 0.50 mg/mL.

Open the reconstitution calculator

IGF-1 LR3 — Frequently Asked Questions

What is IGF-1 LR3 and how does it work?

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is an 83-amino acid analogue of human IGF-1 with an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications dramatically reduce binding to IGF binding proteins (IGFBPs), increasing its bioavailability and half-life compared to native IGF-1. It acts through the IGF-1 receptor to promote cell proliferation, protein synthesis, and glucose uptake in research models.

What research has been done on IGF-1 LR3?

Published research in Endocrinology demonstrated that IGF-1 LR3 has approximately three times the potency of native IGF-1 due to reduced IGFBP sequestration. Studies in the Journal of Cellular Physiology showed enhanced myoblast proliferation and differentiation. Additional research has explored its role in satellite cell activation for muscle repair, pancreatic beta-cell proliferation, and neuroprotective mechanisms in CNS injury models.

How does IGF-1 LR3 compare to native IGF-1 or MGF?

Native IGF-1 is rapidly bound by IGFBPs (especially IGFBP-3), reducing its free fraction and bioactivity. IGF-1 LR3's structural modifications keep it largely unbound, resulting in higher and more sustained IGF-1 receptor activation. MGF (Mechano Growth Factor) is a splice variant of IGF-1 that acts locally in damaged tissue. IGF-1 LR3 has a more systemic action profile, making it useful for different research questions.

What is the recommended reconstitution protocol for IGF-1 LR3?

For this 1mg vial, add 1 mL of bacteriostatic water to yield a concentration of 1.0mg/mL. Draw 5 units on a 1mL insulin syringe for a 50 mcg dose. Inject BAC water slowly along the inner vial wall — do not shake. Allow the powder to dissolve fully (2–5 minutes). Administer in the AM for 10 days in a row, then take 4 weeks off before the next cycle. Refrigerate reconstituted solution at 2–8°C and use within 30 days.

Is IGF-1 LR3 legal to buy for research?

IGF-1 LR3 is sold in the United States as a research chemical for laboratory and in-vitro use only. It is not approved by the FDA for human use and is not sold for human consumption. Researchers are responsible for compliance with all applicable federal, state, and institutional regulations.

How is IGF-1 LR3 reconstituted for research use?

IGF-1 LR3 ships as a lyophilized (freeze-dried) powder and is reconstituted with bacteriostatic or sterile water before use in research. The volume of solvent added determines the working concentration — use the Elyte reconstitution calculator to derive the exact concentration for a given vial size and solvent volume.

Does IGF-1 LR3 come with a Certificate of Analysis?

Yes. Every batch of IGF-1 LR3 from Elyte Peptides ships with a third-party Certificate of Analysis (COA) documenting identity and HPLC purity (≥98%), so research results can be traced to a verified lot.

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