IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3) is a synthetic, modified analog of the naturally occurring hormone IGF-1, which is produced primarily in the liver in response to growth hormone (GH) stimulation. The “LR3” refers to a structural modification: an arginine (R) substitution at position 3 and a 13-amino-acid extension at the N-terminus. This alteration extends its half-life from ~20 minutes (for natural IGF-1) to 20-30 hours, making it more potent and longer-acting.

Key Properties and Mechanism

• Structure: 83 amino acids (vs. 70 in native IGF-1). The changes reduce binding to IGF-binding proteins (IGFBPs), allowing more free hormone to interact with IGF-1 receptors.
• Primary Effects:

Common Uses

• Bodybuilding/Athletics: Injected post-workout (20-100mcg/day, often site-specific into muscles). Stacked with steroids/GH for “recomp” (muscle gain + fat loss).
• Research: Studied for muscle-wasting conditions (e.g., sarcopenia, muscular dystrophy). Patented by GroPep (now part of Teva); not FDA-approved for human use.
• Dosage Example (anecdotal, not medical advice):

Side Effects & Risks

• Common: Hypoglycemia (if overdosed), joint pain, water retention, organ growth (intestines, heart – “GH gut”).
• Serious: Potential cancer promoter (IGF-1 linked to proliferation in prostate/breast cancers; meta-analysis in Lancet Oncol, 2009). Insulin resistance leading to type 2 diabetes.
• Legality: Research chemical in most countries; Schedule 4 in Australia, banned by WADA for athletes. Often sold gray-market (purity varies 50-90%).

Sourcing & Storage

• Purity Check: Reputable labs use HPLC/MS; avoid if not third-party tested (e.g., Janoshik). Reconstitute with acetic acid (0.6%), store lyophilized at -20°C (stable 2+ years), refrigerated solution lasts 30 days.
• Half-Life Math: ~20-30h allows once-daily dosing; steady-state reached in ~5 days.

Evidence Basis: Derived from peer-reviewed sources (PubMed: >5,000 IGF-1 papers), animal/human trials (e.g., J Clin Endocrinol Metab), and pharmacokinetic studies (e.g., Growth Horm IGF Res, 2002). Not medical advice – consult a doctor; self-experimentation carries risks. For protocols, see r/PEDs or MorePlatesMoreDates analyses.