What is IGF-1 LR3?
IGF-1 LR3 (Long Arg3 IGF-1) is a recombinant analog of human insulin-like growth factor 1 (IGF-1). Compared with natural IGF-1 (70 amino acids), it has arginine in place of glutamic acid at position 3, plus a 13-amino-acid extension at the start of the chain, for 83 amino acids in total. These changes mean it binds only weakly to the IGF-binding proteins that normally hold IGF-1 inactive, so it stays active for longer. It is widely used as a growth supplement in cell culture and in research on the IGF-1 receptor.
You may also see it sold as “receptor grade IGF-1 LR3”. That is a supplier label for material intended for cell culture and receptor studies, not a different compound. Check the certificate of analysis for your batch for its tested specification.
IGF-1 LR3 product specifications
- Compound: IGF-1 LR3 (Long R3 IGF-1)
- Structure: human IGF-1 with Glu3 to Arg3 substitution and a 13-amino-acid N-terminal extension (83 amino acids)
- Molecular formula: C400H625N111O115S9
- Molecular weight: about 9,118 g/mol (9.1 kDa)
- Vial sizes: 0.1mg (100mcg) or 1mg
Available sizes: 100mcg and 1mg
IGF-1 LR3 is offered in two vial sizes. Both contain the same compound. The figure is the total amount of protein in the vial, supplied as a dry (lyophilised) powder; it is not a concentration. A concentration only exists once a lab dissolves the powder, and it depends on how much solvent is used.
- 0.1mg (100mcg): the smaller vial. Note that 100mcg and 0.1mg are the same amount, written in different units (1mg = 1,000mcg).
- 1mg (1,000mcg): ten times the material of the small vial, for larger or repeated experiments from one batch.
Choose the size from the options on this page, then contact us on Telegram or by email for availability.
Regulatory status
IGF-1 LR3 is not an approved medicine in the US, UK, EU or Canada. IGF-1 and its analogs are on the World Anti-Doping Agency (WADA) Prohibited List. This product is sold for laboratory research use only.
Related research peptides
- MGF (mechano growth factor) is a peptide based on a splice variant of IGF-1.
- PEG-MGF is a PEGylated form of MGF.
Handling and research-use notice
Store and handle this material as stated on the label and certificate of analysis for your batch; see our guide to storing research peptides. This product is sold for laboratory research use only. It is not a medicine or supplement and is not for human or veterinary use.




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