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IGF-1 LR3

Long R3 IGF-1, Long-Arg3-IGF-1

Research useEducational entry
Mechanism

A long-acting analogue of insulin-like growth factor 1 with a 13-amino-acid N-terminal extension and an Arg3 substitution that reduces binding to IGF-binding proteins by roughly 1,000-fold, giving a much longer half-life while it activates the IGF-1 receptor (IGF1R).

Evidence

Characterised mainly as a cell-culture reagent and research analogue; there is no clinical evidence base for human use. Not an approved drug.

Applications
  • Used as a serum-free cell-culture growth supplement
  • Research analogue for sustained IGF1R activation
  • Studied in muscle, bone and metabolic signalling models
Protocol

Educational overview only — no dosing instructions in the public hub.

Risks

Serious hypoglycaemia risk from insulin-like activity; sustained IGF1R activation raises theoretical concerns for tissue overgrowth and oncogenic signalling; prohibited in sport (WADA Prohibited List, class S2); long-term human safety unknown; sourcing/purity is a major practical risk.

Quality

Third-party CoA (purity + quantification + MS) is the minimum verification.

Legal status

Research-use-only; not approved for human use; prohibited in sport under WADA class S2 (peptide hormones/growth factors).

✓ Last reviewed · 2026-07-21

Frequently asked questions

What is IGF-1 LR3 used for?
Used as a serum-free cell-culture growth supplement. Research analogue for sustained IGF1R activation. Studied in muscle, bone and metabolic signalling models. Characterised mainly as a cell-culture reagent and research analogue; there is no clinical evidence base for human use. Not an approved drug.
Is IGF-1 LR3 legal in Europe?
Research-use-only; not approved for human use; prohibited in sport under WADA class S2 (peptide hormones/growth factors).
What are the risks and side effects of IGF-1 LR3?
Serious hypoglycaemia risk from insulin-like activity; sustained IGF1R activation raises theoretical concerns for tissue overgrowth and oncogenic signalling; prohibited in sport (WADA Prohibited List, class S2); long-term human safety unknown; sourcing/purity is a major practical risk.
How is the quality of IGF-1 LR3 assessed?
Third-party CoA (purity + quantification + MS) is the minimum verification.