Growth Factors
IGF-1 LR3
Insulin-like growth factor-1 LR3
Long R3 Insulin-like Growth Factor-1
Research context
IGF-1 LR3 carries an arginine substitution at position 3 and a 13-residue N-terminal extension. Published characterisation reports substantially reduced affinity for IGF binding proteins relative to native IGF-1 — the property that makes it useful in cell culture where binding-protein interference confounds results.
Common assays: IGF-1R binding · IGFBP affinity comparison · Cell proliferation assays
Specification
| Designation | Insulin-like growth factor-1 LR3 |
|---|---|
| Full name | Long R3 Insulin-like Growth Factor-1 |
| Sequence | 83-residue IGF-1 analogue with Arg3 substitution and 13-residue N-terminal extension |
| CAS number | 946870-92-4 |
| Molecular formula | C400H625N111O115S9 |
| Molecular weight | 9111.00 g/mol |
| Formats | 10 mL Vial |
| Solubility | Dilute acetic acid; limited solubility at neutral pH |
| Storage | Lyophilised: −20 °C. Reconstituted: 2–8 °C, use promptly. |
| Regulatory status | Not an approved drug. Not on the FDA 503A interim category lists as of October 2026. 2026 status by compound → |
| Current lot | IGF1VAS0426 → |
IGF-1 LR3 COA: certificates of analysis by lot
One lot of IGF-1 LR3 has a published certificate of analysis from AxisPharm, LLC, an independent laboratory. Each certificate reports the laboratory's results for that lot.
| Lot | Format | Purity (HPLC-UV) | Reported |
|---|---|---|---|
| IGF1VAS0426 | 1 mg Vial | >99.3% | 2026-04-30 |
Published literature
Selected peer-reviewed references describing research involving this compound. Listed for reference only; inclusion is not a claim about any outcome.
- Francis GL, Ross M, Ballard FJ, et al.Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potencyJournal of Molecular Endocrinology · 1992 Find on PubMed ↗
Common questions
Why is IGF-1 LR3 used in cell culture rather than native IGF-1?
Its reduced affinity for IGF binding proteins means less interference from binding proteins present in serum-containing media, giving more consistent receptor engagement.
Why does IGF-1 LR3 require acidic solvent?
Solubility is poor at neutral pH. Dilute acetic acid is standard for stock preparation, with dilution into buffer immediately before use.
Where can I see the IGF-1 LR3 certificate of analysis?
Every published IGF-1 LR3 lot has its own certificate page on this site, listed under "IGF-1 LR3 COA" above. There is one published lot; the most recent, lot IGF1VAS0426, was reported on 2026-04-30 at >99.3% purity by HPLC-UV. The certificates are issued by AxisPharm, LLC, an independent laboratory.
Components, blends and pathway
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