An 83-amino-acid engineered variant of human IGF-1 with two modifications: an N-terminal 13-amino-acid extension peptide and an arginine-to-glutamic acid substitution at position 3. These modifications reduce IGF binding protein (IGFBP) affinity by >100-fold, dramatically increasing free IGF-1 bioavailability and extending the functional half-life from ~15 minutes (native IGF-1) to 20–30 hours.
Research FocusIGF-1 signaling without IGFBP buffering, muscle hypertrophy, cell proliferation, PI3K/Akt pathway
ReconstitutionAcetic acid (0.1M) or bacteriostatic water — 100 mcg/mL
Stability28 days at 2–8°C; acid-reconstituted preferred
Key distinction: >100-fold reduced IGFBP binding delivers free IGF-1 directly to receptors — enabling study of unsequestered IGF-1R activation not achievable with native IGF-1.
Scientific Evidence
Published Research
[1]
Francis GL 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 potency. J Mol Endocrinol 1992;8:213-223 — PubMed 1381175
[2]
Tomas FM et al. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins. Am J Physiol 1993;264:E361-E367 — PubMed 7681259
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