Growth Hormone · Peptide Reference · Updated 2026-05-11

IGF-1 LR3

Modified IGF-1 with a 13-aa N-terminal extension and Arg3 substitution that prolongs half-life (~20 hours vs 10 minutes for native IGF-1) by reducing IGF-binding protein affinity. Used for lean mass support and recovery.

Growth Hormone Evidence grade: C Not FDA-approved
SS
Editorial team
Dr. Sam Saberian · Lead Medical Researcher
Medical review by Alen A. Schwartz, MD · Edited by Julliana Edwards · Last updated 2026-05-11

Key facts

Class
Modified insulin-like growth factor
Half-life
~20 hours (long-acting analog)
Pharmacy pathway
503A compounding
Sports-ban status
WADA prohibited (S2)
Key concern
Hypoglycemia risk; insulin-like action
Common dose
20-40 mcg SC daily
Evidence grade
C (animal studies; bodybuilding-community use)
FDA status
Not FDA-approved

Mechanism of action

Modified IGF-1 with a 13-aa N-terminal extension and Arg3 substitution that prolongs half-life (~20 hours vs 10 minutes for native IGF-1) by reducing IGF-binding protein affinity. Used for lean mass support and recovery.

Standard dosing

Typical clinical use: 20-40 mcg SC daily. Dosing varies by indication and provider protocol; this is reference-only and not a prescribing recommendation. IGF-1 LR3 requires a prescription from a licensed clinician.

Regulatory status & pharmacy pathway

Not FDA-approved. Compounded peptides are dispensed via 503A licensed compounding pharmacies (USP <797> sterile compounding) or 503B FDA-registered outsourcing facilities (cGMP). Patients should request the pharmacy of record and certificates of analysis (USP <71> sterility, USP <85> endotoxin, HPLC potency) for every shipment.

U.S. telehealth providers prescribing IGF-1 LR3

The most commonly cited U.S. telehealth providers for IGF-1 LR3 are Defy Medical, Marek Health, Hone Health, Maximus, and PeterMD — all of which offer prescriber-supervised access with lab integration and 503A pharmacy partnerships. See the full provider directory for complete profiles.

Trade-offs to know

IGF-1 LR3 carries the trade-offs common to all compounded peptide therapeutics: not FDA-approved (when applicable), cash-pay only, no in-network insurance coverage, and pharmacy-quality variation between providers. Choose a prescriber that publishes pharmacy of record, per-vial CoAs, and lab-integrated follow-up.

Related peptides in the growth hormone category

Editorial team

Authored by Dr. Sam Saberian, medically reviewed by Alen A. Schwartz, MD, edited by Julliana Edwards. About our team →