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Moderate Evidence

IGF-1 LR3 (S2)

Insulin-like Growth Factor-1 Long R3

A long-acting analog of IGF-1 with enhanced receptor binding and extended half-life for anabolic and recovery effects.

Prohibited in competition. This compound is on the WADA Prohibited List (class [S0 / S2.3 / S2]), banned at all times, both in and out of competition. Athletes subject to WADA or USADA testing should not use it.

100% 50% · t½ ≈ 20h 25% 0h 20h 40h 60h 80h Serum level Time →
Molecular Weight 9117.5 Da
Half-Life ~20 hours
Typical Dose 20–100 mcg
Cycle Length 4–6 weeks (with breaks)

Description

IGF-1 LR3 is a recombinant analog of insulin-like growth factor-1 with an arginine substitution at position 3 and an N-terminal 13 amino acid extension. These modifications reduce binding to IGF-binding proteins, extending its half-life from ~12 minutes to ~20 hours and enhancing its biological activity.

Key Characteristics

Molecular Formula

C400H625N111O115S9

Molecular Weight

9117.5 Da

Half-Life

~20 hours

Administration Routes

Subcutaneous injection, Intramuscular injection

Typical Dose

20–100 mcg

Frequency

Daily or every other day

Investigated Benefits

  • Enhanced muscle protein synthesis
  • Accelerated muscle recovery
  • Improved body composition
  • Anti-aging effects
  • Neuroprotection

* Benefits based on preclinical/animal research unless otherwise noted.

Mechanism of Action

“A long-acting analog of IGF-1 with enhanced receptor binding and extended half-life for anabolic and recovery effects.”

IGF-1 LR3 binds to IGF-1 receptors throughout the body, activating PI3K/Akt and MAPK signaling pathways that promote cell growth, protein synthesis, and anti-apoptotic effects. It stimulates satellite cell activation for muscle repair and promotes glucose uptake.

Administration Routes

Subcutaneous injection

Intramuscular injection

Dosing Protocol

Typical Dose

20–100 mcg

Frequency

Daily or every other day

Cycle Length

4–6 weeks (with breaks)

Administration

Subcutaneous injection

Protocol Notes

Use in short cycles (4–6 weeks) with equal breaks to prevent receptor desensitization. Post-workout injection maximizes anabolic effects. Monitor blood glucose — can cause hypoglycemia.

Reconstitution Guide

Add 1 mL bacteriostatic water to 1 mg vial → 1000 mcg/mL For 50 mcg dose: draw 0.05 mL (5 units on U-100 syringe)

Storage Information

Lyophilized: refrigerate. Reconstituted: refrigerate and use within 14 days.

Quality & Sourcing Standards

When sourcing IGF-1 LR3 for research purposes, the following quality benchmarks should be verified before use.

Purity:

>98% (verified by HPLC)

Certificate of Analysis (COA):

Must be provided by supplier

Endotoxin Testing:

<0.1 EU/mg (prevents bacterial contamination)

GMP Compliance:

Manufactured in cGMP-certified facility

Third-Party Testing:

Independent lab verification preferred

Storage Information

Lyophilized: refrigerate. Reconstituted: refrigerate and use within 14 days.

FDA Disclaimer

The statements made within this website have not been evaluated by the US Food and Drug Administration. The products and information provided are not intended to diagnose, treat, cure, or prevent any disease. This website is intended for educational and research purposes only. Many peptides described on this site are not approved by the FDA for human therapeutic use and are classified as research chemicals. Nothing on this site constitutes medical advice.

Research Highlights

1

Extended half-life vs native IGF-1 demonstrated in pharmacokinetic studies

2

Enhanced anabolic effects in multiple animal models

3

Neuroprotective effects in CNS injury models

Evidence Level

Moderate Evidence
Multiple animal studies and/or early human trials. Reasonable confidence in mechanism, but human data is limited.

Search PubMed: “IGF-1 LR3” — latest studies
Google Scholar: IGF-1 LR3 research literature

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Quick Reference

Category

Hormone & GH

Status

Research Only

Dose

20–100 mcg

Frequency

Daily or every other day

Cycle

4–6 weeks (with breaks)
  • Research

PubMed: IGF-1 LR3 studies

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Dislcaimer

FDA Disclaimer: The statements made within this website have not been evaluated by the US Food and Drug Administration. The products and information provided are not intended to diagnose, treat, cure, or prevent any disease. This website is intended for educational and research purposes only. Many compounds described on this site are not approved by the FDA for human therapeutic use. Some are available only as compounded preparations or as materials sold for laboratory use, and several are on FDA's Category 2 list for significant safety risks. Nothing on this site constitutes medical advice or a recommendation to use any compound described.