PepWisePepWise
App Store Google Play
Start free

Peptide Encyclopedia / IGF-1 LR3

Encyclopedia

IGF-1 LR3

IGF-1 LR3 is a synthetic insulin-like growth factor 1 analog engineered to resist the binding proteins that limit IGF-1, so it circulates as free hormone and activates the IGF-1 receptor. No controlled human trials support it, it is not FDA-approved, and WADA bans it at all times. Below you'll find reported dosing, reconstitution, safety, and legal status. Educational only, not medical advice.

Track IGF-1 LR3 →Dose tools
CategoryGrowth Hormone
Regulatory statusNot FDA-approved for any human indication.

Mechanism

A synthetic analog of insulin-like growth factor 1 with an Arg substitution at position 3 and a 13-amino-acid N-terminal extension, which greatly reduces binding to IGF-binding proteins so it circulates mostly as free, active hormone and directly activates the IGF-1 receptor to drive cell growth and protein synthesis.

Half-life

Reported in the range of ~20-30 hours (vendor/research figures); robust human pharmacokinetic data are limited. It is a peptide/protein analog, not a small molecule.

Regulatory status

Not FDA-approved for any human indication. Sold as a research chemical / for laboratory use only. Exogenous IGF-1 and its analogs are prohibited at all times by WADA.

Safety

Commonly cited concerns include hypoglycemia, edema, jaw/organ growth, and a theoretical increase in cancer risk via IGF-1 receptor signaling. Long-term human safety is essentially unstudied for this analog.

Evidence

No controlled human trials of the LR3 analog for performance/anti-aging; primarily preclinical/cell-culture data plus anecdotal use.

Track IGF-1 LR3 in PepWise

Log every dose and injection site, get the reconstitution and units math automatically, follow your cycle, and record how you feel, then export a provider report. IGF-1 LR3 tracker, free to start.

Sources

  1. Yoshida T, Delafontaine P. Mechanisms of IGF-1-Mediated Regulation of Skeletal Muscle Hypertrophy and Atrophy. Cells. 2020;9(9):1970. https://pubmed.ncbi.nlm.nih.gov/32858949/
  2. Barton-Davis ER, et al. Contribution of satellite cells to IGF-I induced hypertrophy of skeletal muscle. Acta Physiol Scand. 1999;167(4):301-305. https://pubmed.ncbi.nlm.nih.gov/10632630/
  3. Tomas FM, et al. 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. J Endocrinol. 1997;155(2):377-386. https://pubmed.ncbi.nlm.nih.gov/9415072/
  4. Conlon MA, et al. Long R3 IGF-I infusion stimulates organ growth but reduces plasma IGF-I in the guinea pig. J Endocrinol. 1995;146(2):247-253. https://pubmed.ncbi.nlm.nih.gov/7561636/

PepWise is an informational and educational tracking tool, not medical advice and not a medical device. IGF-1 LR3 may be experimental, restricted, or prescription-only; many research peptides are not FDA-approved. Consult a licensed healthcare provider before starting, changing, or stopping any protocol. Operated by STC Consulting, Inc.