Third-Party Tested by Verum Analytics
IGF-1 LR3
Long R3 IGF-1 — ~3x more potent than native IGF-1 with an extended 20–30 hour half-life for muscle-growth research.
Third-Party Tested by Verum Analytics
Albert's Verdict
The LR3 modification extends the half-life to roughly 20–30 hours versus the native form's minutes — that sustained receptor occupancy is what makes the downstream mTOR and PI3K signaling data so interesting. Worth the wait when it's back in stock.
View COA✓ In stock - Ships same day
Arrives as lyophilized (powder) form
Shipped freeze-dried for maximum stability and shelf life. See laboratory preparation guide for handling instructions.
Product Description
IGF-1 LR3 (Long R3 Insulin-Like Growth Factor-1) is a synthetic 83-amino acid analog of human IGF-1 modified with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These modifications dramatically reduce binding to IGF-binding proteins, resulting in approximately 3x greater potency and a 20–30 hour half-life vs the native peptide.
One of the most powerful research peptides available for muscle-growth studies — animal-model data documents both hypertrophy (larger muscle fibers) and hyperplasia (increased fiber count). A staple of anabolic and tissue-growth research protocols. For research use only. Not for human or veterinary consumption.
Technical Specifications
- Molecular Formula
- C400H625N111O115S9
- Molecular Weight
- 9117.5 g/mol
- Sequence
- 83 amino acid sequence
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Frequently Researched Together
Commonly studied alongside in laboratory settings
Learn More About This Peptide
Research Use Only: This product is intended for laboratory research purposes only. Not for human consumption.
IGF-1 LR3 — clinical & mechanistic profile
IGF-1 LR3 is a synthetic 83-amino-acid IGF-1 analog with an Arg3 substitution and 13-aa N-terminal extension that reduces IGFBP binding, extending half-life from ~15 min to 20-30 hours. Activates PI3K/Akt/mTOR pathway for protein synthesis while suppressing FoxO-mediated ubiquitin-proteasome degradation via GSK3β inhibition.
Research status
preclinical
Molecular weight
9111.2 g/mol
Molecular formula
C400H625N111O115S9
Studied applications
- •Extended half-life: 20-30 hours vs. ~15 min for native IGF-1 due to reduced IGFBP binding
- •PI3K/Akt/mTOR activation: stimulates protein synthesis via mTOR, S6K1, and 4E-BP1 phosphorylation
- •Catabolic suppression: inhibits FoxO transcription factors and E3 ubiquitin ligases, reducing proteolysis
- •GH synergy: co-administration with GH enhances anabolism; GH drives endogenous IGF-1 production
- •Satellite cell activation: stimulates muscle stem cell proliferation and differentiation for hypertrophy
Mechanisms of action
- •IGF-1R activation: binds IGF-1 receptor tyrosine kinase, triggering autophosphorylation and IRS-1 recruitment
- •PI3K/Akt cascade: activates protein synthesis via mTOR, S6K1, 4E-BP1; increases ribosome biogenesis
- •GSK3β inhibition: Akt-mediated inhibition prevents glycogen synthase inactivation and muscle catabolism
- •FoxO suppression: phosphorylation causes nuclear exclusion, reducing atrogene and E3 ligase expression
- •Insulin receptor cross-activation: lower-affinity activation of insulin receptor amplifies effects post-exercise
- •Reduced IGFBP interaction: N-terminal extension and Arg3 substitution prevent binding protein sequestration
- •Not approved for human use in any jurisdiction
- •Prohibited by WADA under S2 category (Peptide Hormones, Growth Factors)
- •Potent growth factor activity raises significant safety concerns including cancer risk
- •No human clinical trials conducted for any indication
- •Hypoglycemia risk due to structural similarity to insulin
Peer-reviewed references
For research use only. This summary is a research-scientific overview compiled from peer-reviewed sources. It is not medical advice and is not intended for human or veterinary consumption.