IGF-1 LR3
Insulin-like growth factor 1 (Long R3)
Long-acting growth factor.
Half-life
~ longer than native IGF-1
Mol. weight
9200 g/mol (approx)
Sequence
Modified IGF-1 (Long R3 analog)
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Overview
A modified analog of insulin-like growth factor 1 with an extended half-life and reduced affinity for IGF-binding proteins, researched for muscle growth and recovery. Where GH secretagogues stimulate the top of the GH axis, IGF-1 LR3 delivers the downstream mediator directly — producing potent anabolic signaling but also genuine insulin-like metabolic effects including hypoglycemia risk.
Mechanism of action
IGF-1 LR3 binds IGF-1 receptors to promote cell proliferation and muscle hypertrophy. The 'Long R3' modifications — an arginine substitution at position 3 and an extended N-terminal — reduce its binding to IGF-binding proteins (IGFBPs), leaving more free, active peptide compared to native IGF-1. This extends its functional half-life and increases receptor exposure, which amplifies the anabolic signal but also the insulin-like metabolic effects (glucose uptake), the source of its hypoglycemia risk.
Researched benefits
- Studied for muscle hypertrophy and cell proliferation
- Extended activity vs native IGF-1
- Reduced binding-protein sequestration
Considerations
- Potent insulin-like effects — real hypoglycemia risk
- Suppresses the natural GH→IGF-1 axis
- Strictly research context; medical supervision essential
Key Academic Literature & Studies
Search more in PubMedPeer-reviewed citations and clinical trials evaluating IGF-1 LR3 in scientific literature.
Query PubMed for recent peer-reviewed preclinical and clinical publications on IGF-1 LR3:
View IGF-1 LR3 index on PubMed (NCBI)