IGF-1 LR3
Muscle Research only Animal studies
Also called Long R3 IGF-1, Long Arg3 IGF-I
A lab-made version of insulin-like growth factor 1, rebuilt with a 13-amino-acid extension and one substitution so it mostly escapes the binding proteins that normally mop up IGF-1. The result stays active far longer than the natural hormone.
Why people take it
What studies report
- Potent activation of the IGF-1 receptor in cultured cells
- Longer activity than native IGF-1 because it evades IGF-binding proteins
- Standard reagent for serum-free cell culture
In practice Unapproved use
- Used in bodybuilding, typically post-workout and in short runs
- Short runs are deliberate — the community treats long exposure as risky
Reported real-world use, not evidence and not a recommendation.
Worth knowing: Essentially all data is cell culture, where it is sold as a laboratory reagent. IGF-1 signalling drives cell growth broadly, so sustained elevation carries a real theoretical cancer concern, and it can cause low blood sugar.
Status: Sold as a cell-culture reagent. Not approved for human use.
- Route
- Subcutaneous injection, from reconstituted lyophilised powder
- Molecular weight
- 9111.5 (≈9.1 kDa)
- CAS
- 143045-27-6
- Available as
- 10 mg
Educational information only. Nothing here is medical advice, a dosing protocol, or a recommendation to use any compound. Most entries describe substances not approved for human use. Talk to a licensed clinician before acting on anything you read here. How to read these entries.