IGF-1 LR3: How It Works, What It's Studied For & Safety
IGF-1 LR3 is a modified analog of insulin-like growth factor-1 with a longer half-life and reduced binding to IGF-binding proteins, studied historically in cell-culture research and in research-informed body-composition protocols. Clinicians consider it for cell-culture and preclinical anabolic-signaling research (its primary historical use). Not FDA-approved; dispensed by Wells Pharmacy Network only after a clinician evaluation.
Also known as: Long R3 IGF-1, Insulin-like Growth Factor-1 Long R3
How does IGF-1 LR3 work?
IGF-1 LR3 is recombinant IGF-1 with an N-terminal 13-amino-acid extension and an Arg substitution at position 3, giving it a longer plasma half-life and weaker binding to IGFBPs - so a higher fraction is bioavailable. It engages the IGF-1 receptor, driving anabolic protein synthesis and glucose uptake similar to native IGF-1.
What is IGF-1 LR3 studied for?
- Cell-culture and preclinical anabolic-signaling research (its primary historical use)
- Adjunct in clinician-directed body-composition protocols (off-label, investigational)
- Research on IGF-1 receptor pharmacology
How is IGF-1 LR3 taken?
Compounded as a subcutaneous injection in clinician-directed protocols. Not FDA-approved as a finished drug. The FDA-approved native IGF-1 product (mecasermin) is approved only for severe primary IGF-1 deficiency in children.
Is IGF-1 LR3 FDA-approved? Is it safe?
Not FDA-approved for the prevention, treatment, or cure of any condition. Used inside research-informed, clinician-directed protocols only. Hypoglycemia is a known IGF-1 effect and is more pronounced with LR3 because of reduced IGFBP buffering. Theoretical concerns about promotion of occult tumors require clinician judgment in patients with cancer history. Compounded prescription-only preparations are dispensed by Wells Pharmacy Network. Eligibility is decided by a licensed clinician based on intake and labs, not by checkout. Compounded products on this site are not FDA-approved and are not generic equivalents of any branded medication.
In the Regen Therapy catalog
This compound does not currently appear in an active Regen Therapy protocol. Browse the full catalog for adjacent options.
What does the research say about IGF-1 LR3?
Used as a research-grade ligand for decades. Controlled human-outcome trials of LR3 itself are not available; safety inferences are extrapolated from native IGF-1 (mecasermin) data.
Citations & further reading
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