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IGF-1LR3 1mg

Research Specifications

Full Name:
Long R3 Insulin-like Growth Factor-1
Modification:
13 aa N-terminal extension + Arg3→Glu3 substitution
Molecular Weight:
9,117 Da
Form:
Lyophilized powder
Purity:
≥98% (SDS-PAGE and HPLC verified)
Storage:
−80°C ideal; −20°C acceptable; 4°C up to 7 days reconstituted
Reconstitution:
Acetic acid (0.1%) or bacteriostatic water with 0.1% BSA carrier

IGF-1LR3 1mg

Long R3 IGF-1 — 83-amino acid analogue of insulin-like growth factor-1 with 3× longer half-life. Researched for skeletal muscle protein synthesis, satellite cell activation, and lean mass accrual.

~20-30h

Half-life (vs 15 min native)

IGFBP-independent activity

83

Amino Acids

+13 N-terminal extension

9.1 kDa

Molecular Weight

LR3 analogue

Receptor Targets

IGF-1R↑ protein synthesis (mTOR), ↑ satellite cell activation, ↑ glucose uptake
IR (partial)Modest insulin receptor cross-reactivity — monitor glucose
$79.99In Stock
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≥98% Purity Verified Free Shipping $200+ HPLC Tested

IGF-1 Receptor Agonism & PI3K/mTOR Activation

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a recombinant analogue of human IGF-1 with an N-terminal 13-amino acid extension and an Arg→Glu substitution at position 3. These modifications dramatically reduce its affinity for IGF binding proteins (IGFBPs), which normally sequester ~98% of circulating IGF-1. The result is a half-life of ~20-30 hours vs ~15 minutes for native IGF-1. IGF-1 LR3 binds the IGF-1 receptor (IGF-1R), activating the PI3K/Akt/mTOR and Ras/MAPK pathways — driving skeletal muscle protein synthesis, satellite cell (muscle stem cell) activation and differentiation, anti-apoptotic signaling, and glucose uptake into muscle tissue.

Research Highlights

Skeletal Muscle Hypertrophy Research

IGF-1 LR3 activates mTORC1 via PI3K/Akt, the central regulator of muscle protein synthesis. In rodent models, IGF-1 overexpression or exogenous IGF-1 LR3 produces dose-dependent muscle hypertrophy, increased fiber cross-sectional area, and satellite cell proliferation. The extended half-life of LR3 vs native IGF-1 amplifies these effects over a research window.

Satellite Cell Activation

IGF-1 signaling is a primary regulator of satellite cell (muscle stem cell) quiescence/activation. IGF-1 LR3 in vitro and in vivo promotes satellite cell entry into the cell cycle, differentiation into myoblasts, and fusion with existing myofibers — the cellular mechanism of muscle repair and hypertrophy. This makes it particularly relevant to research examining muscle regeneration after atrophy.

Lean Mass Preservation in Caloric Restriction Research

In caloric restriction models where GLP-1 agonists reduce total body weight, IGF-1 signaling supports the preservation of lean mass. Research protocols pairing IGF-1 LR3 with tirzepatide or retatrutide investigate whether exogenous IGF-1 activity can maintain anabolic signaling in muscle during significant caloric deficit — directly relevant to body composition outcomes in looksmaxxing research.

Research FAQ

What is the difference between IGF-1 and IGF-1 LR3?
Native IGF-1 (70 aa) is rapidly bound by IGF binding proteins (IGFBP-1 through -6), reducing its free concentration to ~2% of total. The half-life is ~15 minutes for free IGF-1. IGF-1 LR3 has ~1000-fold lower IGFBP affinity due to its N-terminal extension and Arg3→Glu3 substitution, giving a half-life of 20-30 hours and substantially higher bioavailability for receptor engagement.
Does IGF-1 LR3 affect blood glucose?
IGF-1R and the insulin receptor share structural homology. IGF-1 LR3 has partial insulin receptor cross-reactivity and can lower blood glucose in research settings — this must be monitored in protocols. Its glucose-lowering effect is significantly weaker than insulin but non-negligible, particularly at higher research doses.
How should IGF-1 LR3 be reconstituted?
Standard protocol: reconstitute in 0.1% acetic acid (1mg in 1mL = 1mg/mL), then dilute to working concentration using PBS or saline with 0.1% BSA (bovine serum albumin) to stabilise the protein. BSA prevents adsorption to plastic surfaces. Store reconstituted at −20°C; use working solution within 24-48 hours at 4°C.
How does IGF-1 LR3 complement retatrutide or tirzepatide protocols?
GLP-1/GIP/glucagon agonists reduce fat mass and appetite. IGF-1 LR3 activates the mTOR/protein synthesis pathway in muscle. The combination addresses both sides of body recomposition: reducing fat (GLP-1 axis) while supporting muscle anabolic signaling (IGF-1 axis). This mechanistic pairing is the basis for their inclusion in advanced body recomposition research stacks.

Research Use Only. This product is intended for in-vitro laboratory research only. Not for human consumption, injection, or therapeutic use. Not medical advice. Always consult applicable regulations in your jurisdiction.

Price Comparison

SupplierPurityPriceShipping
Apollo (via ClavTides)>98% HPLC$79.99Free over $200
Generic Research SuppliersVaries (often <95%)Similar–HigherVaries
Pharmaceutical (Rx only)Pharmaceutical gradeNot available for researchRx required

IGF-1LR3 1mg

$79.99

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