Track IGF‑1 LR3 in Peptimes™
IGF-1 LR3 is a modified form of human insulin-like growth factor 1 (IGF-1): arginine in place of its third amino acid, plus a 13-amino-acid extension at the start, 83 amino acids in all. (Source: FDA's substance registry (GSRS).)
Is IGF-1 LR3 FDA-approved?
No. IGF-1 LR3 isn't FDA-approved, and Drugs@FDA lists no application with it as an active ingredient. It isn't mecasermin (Increlex).
IGF-1 LR3
Also: Long Arginine 3-IGF-1, LR3-IGF-1, Long R3 IGF-I
- Status label in the Peptimes Library
- Not FDA-Approved
- Routes in Peptimes
- SubcutaneousIntramuscular
- Updated
- 1 Nov 2026
US regulatory status
What studies have looked at
Each point says who or what was studied and what the study reported, with its source and the date we checked it. These are findings from the sources cited, not advice or a promise of any result.
- In animals or the lab
IGF-1 bound IGF-binding proteins about 1,000 times more strongly than LR3 IGF-1. LR3 IGF-1 was 5 to 10 times as potent in rat muscle cells and about 6 times as potent for growth in female rats, but it was cleared from the blood much faster than IGF-1. Animal and cell data.
Source: PMID 7683526, checked 1 Nov 2026
- In animals or the lab
In pigs, IGF-1 variants that bind poorly to IGF-binding proteins, including LR3 IGF-1, lowered blood glucose 2 to 3 times more potently than IGF-1 and kept it lower for longer. Animal data.
Source: PMID 9415072, checked 1 Nov 2026
How to track it in Peptimes
Add IGF-1 LR3 in My Protocols and set the schedule you already follow: days of the week, times of day and a start date. Peptimes never suggests an amount when you log or schedule a dose. Its Library entry shows the status label “Not FDA-Approved”.
- Routes: subcutaneous or intramuscular. Choose the one that matches each dose.
- Logging: the amount you took, the route and how you feel.
- Injection sites: subcutaneous and intramuscular doses record the site, and Insights shows where you’ve injected and how recently. It never suggests where to inject next.
- Reminders and history: reminders at your times, Dose History, the Calendar and CSV or JSON export work as described on the peptide tracker app page.
Peptimes is a tracking app, not medical advice. Talk to a licensed clinician about your treatment. Peptimes doesn’t sell IGF-1 LR3 or any other compound.
More sources
- FDA, Global Substance Registration System, Long-(Arg3)insulin-like growth factor-I, checked 1 Nov 2026: its sequence of 83 amino acids and the names IGF-1 LR3 and long R3 IGF-I.
- FDA, Drugs@FDA, BLA 021839 (Increlex, mecasermin), checked 1 Nov 2026: the FDA-approved IGF-1 product, which is a different substance.