HomePeptides › IGF-1 LR3

IGF-1 LR3

Long R3 IGF-1

Tier 4 · Preclinical Only
Class
IGF-1 analog
Molecular target
IGF-1 receptor
Sequence / structure
83-aa analog: Arg3 substitution plus 13-aa N-terminal extension
Evidence tier
Tier 4 — Preclinical Only
Category
Growth Hormone Axis

Biology & mechanism

An engineered insulin-like growth factor-1 analog. The Arg3 substitution sharply reduces affinity for IGF binding proteins, and the N-terminal extension further limits sequestration — so far more free peptide reaches the IGF-1 receptor, and potency and duration rise substantially versus native IGF-1. It is a laboratory reagent designed for cell culture, not a therapeutic.

What the research actually shows

Ubiquitous as a cell-culture supplement. There are no controlled human trials. Human use is entirely extrapolated from IGF-1 biology and anecdote.

Regulatory status

Not FDA-approved. Sold as a laboratory reagent. Prohibited in sport (WADA S2).

Safety signals

The most acutely hazardous peptide in this library. IGF-1 receptor agonism produces insulin-like effects — severe hypoglycaemia is a real and rapid risk. IGF-1 signalling is mitogenic, and sustained elevation is epidemiologically associated with certain cancers. Cardiac and renal hypertrophy are documented in animal models.

No usage guidance is published here

Forge Bioenergy does not publish dosing, reconstitution, or administration protocols for any peptide. See our editorial policy for why. If you are considering any substance on this page, that conversation belongs with a licensed physician.

References & further reading

Regulatory status changes. This page reflects our reading of public sources as of July 2026 and should be independently verified before it is relied upon.

Important notice Forge Bioenergy publishes scientific reference information only. Nothing on this site is medical advice, a therapeutic claim, or a recommendation to use any substance in humans. Many peptides described here are not approved by the FDA for any use, and several are approved only for narrow indications under prescription. We do not publish dosing, administration, or usage protocols. Consult a licensed physician before making any medical decision.