IGF-1 LR3
Insulin-like Growth Factor-1 Long R3
Modified IGF-1 with 3x longer half-life. Directly stimulates muscle protein synthesis and satellite cell activation independent of the GH axis. Significant cancer risk concern.
Mechanism of action
Binds IGF-1 receptors on muscle cells directly bypassing the GH-pituitary axis. Activates PI3K/Akt/mTOR pathway driving protein synthesis. Stimulates satellite cell proliferation for muscle fiber repair. Half-life extended to several hours vs minutes for natural IGF-1.
Effects in the body
IGF-1 LR3 acts downstream of GH directly at the muscle cell level. This makes it additive to GH secretagogue protocols rather than redundant. Used in athletic recovery and muscle wasting research but significant safety concerns limit clinical development.
Pros & cons (from the literature)
- Direct muscle protein synthesis stimulation independent of GH axis
- Satellite cell activation for repair
- Additive to GH secretagogue protocols
- Longer half-life than natural IGF-1
- Significant cancer promotion risk via IGF-1R activation
- Hypoglycemia risk — serious concern
- Currently RUO not compoundable
- Very high potential for athletic enhancement misuse
- Potency means dosing errors dangerous
Protocol summary (from published research)
Dosing ranges reproduced from published research literature. Not a prescription, not medical advice.
FDA & regulatory status
Evidence base
Mechanism well established. Preclinical data strong. Human clinical data limited due to cancer risk concerns. Not a compound for general wellness research.
Primary research sources
Peer-reviewed literature referenced throughout this profile is drawn from PubMed, Cell Metabolism, and clinical trial registries cited in the evidence base above.