IGF-1 LR3
high riskAlso: Long R3 IGF-1 · Insulin-like growth factor 1 LR3
IGF-1 LR3 is a recombinant analog of IGF-1 with an N-terminal extension (13 amino acids) and Arg substitution that reduces IGF binding protein affinity, extending half-life from ~10 min to ~20 hours. Potently anabolic in animal models. Human data limited; WADA-prohibited.
Reported Benefits
Anabolic / muscle growth
Consistent anabolic effects in animal models. Human performance data largely anecdotal/extrapolated.
Mechanism of Action
IGF-1 receptor agonist with reduced binding protein affinity; activates PI3K-Akt-mTOR and MAPK pathways driving protein synthesis, cell proliferation, and satellite cell activation.
Hypoglycemia Risk
IGF-1 LR3 has meaningful insulin-like activity. Co-administration with insulin can cause life-threatening hypoglycemia. This is not a theoretical risk — documented severe hypoglycemia cases exist in the performance enhancement community.
Oncogenic Concern
IGF-1 receptor signaling is a primary driver of proliferation in multiple cancers (breast, prostate, colorectal). Chronic IGF-1R upregulation in individuals with undiagnosed malignancies is a serious concern.
Regulatory Status
Research OnlySafety Profile
Side Effects
- •Hypoglycemia
- •Jaw/facial bone growth
- •Soft tissue swelling
- •Potential oncogenic risk (IGF-1R promotes tumor growth)
- •WADA-prohibited
Contraindications
- •Active malignancy
- •Cancer history
- •Insulin-dependent diabetes
- •Acromegaly
Drug Interactions
- •Insulin (severe hypoglycemia risk)
- •Anabolic steroids
Primary Uses
Weekly Briefing
Regulatory updates + new study breakdowns.
For Practitioners
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