Understand the source comparison
IGF-1 LR3 vs Native IGF-1: Mechanism Comparison
IGFBP Binding Affinity 600× lower than native IGF-1 High affinity. Binds >95% of circulating IGF-1 LR3's reduced binding allows systemic bioavailability; native form remains sequestered Half-Life ~13 hours 10–12 minutes Extended half-life enables once-daily do
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- IGFBP Binding Affinity
- 600× lower than native IGF-1
- High affinity. Binds >95% of circulating IGF-1
- LR3's reduced binding allows systemic bioavailability; native form remains sequestered
- Half-Life
- ~13 hours
- 10–12 minutes
- Extended half-life enables once-daily dosing and sustained receptor activation
- Signaling Pattern
- Systemic. Activates receptors throughout body
- Autocrine/paracrine. Local tissue effects only
- LR3 produces whole-body anabolic signaling; native IGF-1 acts tissue-specifically
- Insulin Receptor Activation
- 5–10% of insulin's binding affinity
- <1% cross-reactivity
- LR3 creates measurable glucose partitioning effects; native form does not
- Research Dosing
- 50–100mcg/day subcutaneous
- Not used exogenously in most protocols
- LR3 is the preferred analog for anabolic research due to pharmacokinetic stability