At a glance
- Class
- IGF-1 receptor agonist (growth-factor analogue)
- Receptor targets
- IGF-1R
- Length
- 83 amino acids
- Molecular mass
- ≈ 9.1 kDa
- Origin
- Recombinant analogue of human IGF-1
- Research area
- Growth-hormone axis
- Also known as
- Long R3 IGF-1, LR3 IGF-I
What IGF-1 LR3 is
IGF-1 LR3 has an arginine in place of glutamate at position 3 and a 13-residue extension at the N-terminus. Both changes reduce binding to IGF-binding proteins, so more of the molecule stays free to act on the IGF-1 receptor in culture.
It is far larger than most compounds on this site, closer to a small protein than a short peptide. Its main established use is as a medium supplement for growing mammalian cell lines, including those that produce recombinant biologics.
What the research literature studies
- IGF-1 receptor signalling and cell-proliferation assays
- Effect of IGF-binding-protein affinity on potency in culture
- Serum-free media formulation for biologics manufacturing
Evidence rating: 1/5
Limited, preclinical or single-group. Established as a cell-culture reagent. No published therapeutic trials of the LR3 analogue that we know of. See our methodology for how levels are assigned.
- Potency in culture says nothing about activity in a living organism.
- Large recombinant proteins need activity assays and mass confirmation, not only a purity figure.
Regulatory status
IGF-1 LR3 is not an approved medicine with the MHRA, EMA or FDA. Mecasermin, a different IGF-1 product, is approved for a rare form of growth failure, and that approval does not extend to LR3. Research-grade material must not be used in people or animals.
Reviewed November 2026.
IGF-1 LR3 at Nordapep: sizes and price per mg
Every size, its price and the cost per milligram, so you can choose the best-value vial for your protocol.
Not currently listed at Nordapep.
Compare IGF-1 LR3
IGF-1 LR3 FAQ
Is IGF-1 LR3 a peptide?
At 83 residues and about 9.1 kDa it is usually called a protein or growth-factor analogue, although it is often sold alongside peptides.
What does 'LR3' mean?
'Long' refers to the 13-residue N-terminal extension and 'R3' to the arginine at position 3.
Where can I buy IGF-1 LR3 for research?
Nordapep does not currently list IGF-1 LR3. You can ask Nordapep about availability, or compare related compounds that are in stock.
Is IGF-1 LR3 approved?
IGF-1 LR3 is not an approved medicine with the MHRA, EMA or FDA. Mecasermin, a different IGF-1 product, is approved for a rare form of growth failure, and that approval does not extend to LR3. Research-grade material must not be used in people or animals.
Key terms for IGF-1 LR3
Cite this page
peptide.wiki. (2026). IGF-1 LR3: research peptide profile. peptide.wiki. https://www.peptide.wiki/peptides/igf-1-lr3