IGF-1 LR3
Insulin-like Growth Factor 1 Long Arg3
Evidence & Status
- Preliminary / Experimental
- Preliminary
At a Glance
Long R3 IGF-I is a research variant that must be distinguished from native IGF-1, mecasermin, DES(1-3)-IGF-I, and other analogues. The retained evidence is exact-variant-specific nonhuman research.
Plain English
Researchers study Long R3 IGF-I in nonhuman research. It must not be treated as native IGF-1, mecasermin, DES(1-3)-IGF-I, or a verified clinical product, and no established human pharmacokinetics, dose, route, or long-term safety profile is available.
Overview
Long R3 IGF-I is an IGF-I variant distinguished from native IGF-I by an N-terminal extension and an Arg3 substitution. The approved sources identify and study IGF-I variants, including long R(3)IGF-I, in nonhuman models; they do not support generalized human pharmacokinetics, body-composition use, or dosing.
Research Summary
The retained literature reports variant IGF-I effects in rats, pigs, marmosets, and adolescent monkeys. It is nonhuman evidence and must not be presented as clinical evidence for an exact manufactured Long R3 IGF-I product.
Research Areas
- Muscle hypertrophy
- Tissue repair
- Neuroprotection
- GH axis research
- Metabolic regulation
Safety & Risks
Serious Risks
- Long-term human safety data are not established.
Reported Side Effects
- Potential hypoglycemia is described only in analogue- and animal-study context; human safety is not established.
Legal Status by Region
- United States
- Research only
- United Kingdom
- Research only
- Australia
- Research only
- Canada
- Research only
Citations & Sources
- Anabolic effects of insulin-like growth factor-I (IGF-I) and an IGF-I variant in normal female rats.
Tomas FM et al. · Journal of Endocrinology · 1993
PMID 8371075 · DOI 10.1677/joe.0.1370413
- Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection.
Tomas FM et al. · Journal of Endocrinology · 1996
PMID 8708565 · DOI 10.1677/joe.0.1500077
- IGF-I variants which bind poorly to IGF-binding proteins show more potent and prolonged hypoglycaemic action than native IGF-I in pigs and marmoset monkeys.
Tomas FM et al. · Journal of Endocrinology · 1997
PMID 9415072 · DOI 10.1677/joe.0.1550377
- IGF-I but not the IGF-I variant long R(3)IGF-I increases serum IGFBP-3 in adolescent monkeys.
Wilson ME, Lackey SL · Growth Hormone & IGF Research · 2000
PMID 10753591 · DOI 10.1054/ghir.1999.0139