# IGF-1 LR3

*Also known as: Long R3 IGF-1, LR3*

Long-acting IGF-1 analog engineered to resist binding proteins; muscle-growth research compound.

## Overview

IGF-1 LR3 (Long R3 IGF-1) is a modified analog of insulin-like growth factor 1, engineered with an arginine substitution at position 3 and an extended N-terminal. That modification sharply reduces binding to IGF-binding proteins, leaving more free, active hormone to stimulate the IGF-1 receptor and drive anabolic and muscle-growth signaling. Compared with native IGF-1, the LR3 variant is more potent and longer-acting. Its estimated half-life is roughly 12 hours with around 60% bioavailability, longer than the native peptide. The honest evidence picture is that human pharmacokinetic data is essentially absent and IGF-1 LR3 is not an approved medication. Most of what is known comes from in vitro potency work, animal studies, and the broader IGF-1 literature.

## Pharmacokinetics

- **Model tier:** simple
- **Half-life:** 0.5 days (12 hours)
- **Bioavailability:** 60%

## Dosing

- **Default dose:** 0.05 mg
- **Typical range:** 0.02–0.1 mg
- **Units:** ng/mL

## Source

- **Label:** Estimated
- **Notes:** Arginine-substituted analog with reduced binding proteins and extended half-life.

**Tags:** muscle-building

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**Canonical URL:** https://anabolicdex.com/compounds/igf-1-lr3
**Plot:** https://anabolicdex.com/plot?compound=igf-1-lr3