At a glance
Type
Long-acting IGF-1 analog
Molecular weight
≈9,111 Da
Studied for
IGF-1 receptorCell-culture researchTissue growth
IGF-1 LR3 (Long R3 IGF-1) is an engineered, long-acting analog of insulin-like growth factor 1. It is an 83-amino-acid version of native IGF-1 with two changes — an arginine substitution at position 3 and a 13-amino-acid N-terminal extension — that together make it far more potent in the lab than the natural molecule.
How IGF-1 LR3 works
IGF-1 LR3 binds and activates the IGF-1 receptor just like native IGF-1, but its structural changes drastically reduce how tightly it binds to IGF-binding proteins (IGFBPs) — the carrier proteins that normally sequester circulating IGF-1. With far less of it mopped up, more stays biologically available, giving it a longer effective half-life and roughly threefold greater potency, especially in systems that secrete IGFBPs.
What the research shows
- Foundational characterization (Francis et al., 1992). Long[Arg3]IGF-I analogs showed higher biological potency than native IGF-I, driven by reduced IGFBP interaction.
- Potency by injection (Tomas et al., 1996). LR3 IGF-I kept its superior potency even when given by injection, not just infusion.
- Organ growth in animals (Conlon et al., 1995). LR3 IGF-I infusion stimulated growth of several organs while lowering endogenous IGF and IGFBP levels.
- Cell-culture use (Voorhamme & Yandell, 2006). LONG R3 IGF-I supported serum-free cell growth at concentrations roughly 200× lower than insulin.
A candid note on the evidence: IGF-1 LR3 was engineered as, and is predominantly used as, a cell-culture research reagent; the evidence base is largely laboratory and animal work, and human therapeutic use is not established. Use belongs under a physician’s guidance.
Molecular specification
| Type | Long-acting IGF-1 analog (83 amino acids) |
| Modifications | Arg3 substitution + 13-aa N-terminal extension |
| Molecular weight | ≈9,111 Da (approx.) |
| CAS number | 946870-92-4 |
Quality and sourcing
Every batch of Azzurri Wellness IGF-1 LR3 is compounded through a Registered 503B outsourcing facility under GMP-compliant processes, HPLC-tested for purity and potency, and third-party lab verified. Shipped cold-pack when needed to protect stability.
References
- Francis GL, Ross M, Ballard FJ, et al. Novel recombinant fusion protein analogues of IGF-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. J Mol Endocrinol. 1992;8(3):213–223. PubMed
- Tomas FM, Lemmey AB, Read LC, Ballard FJ. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection. J Endocrinol. 1996;150(1):77–84. PubMed
- Conlon MA, Tomas FM, Owens PC, et al. Long R3 IGF-I infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGFBP concentrations in the guinea pig. J Endocrinol. 1995;146(2):247–253. PubMed
- Voorhamme D, Yandell CA. LONG R3IGF-I as a more potent alternative to insulin in serum-free culture of HEK293 cells. Mol Biotechnol. 2006;34(2):201–204. PubMed
Compiled by the Azzurri Wellness Research Team and checked against the cited literature. Educational only — not medical advice.
