IGF-1 LR3

Long R3 IGF-1 · LR3-IGF-1

Growth HormoneNot ApprovedAnimalResearchSubQIM

Popular for:Muscle protein synthesis, extended half-life IGF-1, anabolic

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Registered Trials

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Trial Publications

10

PubMed References

Animal

Evidence Level

Overview

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified version of IGF-1 with an extended half-life of approximately 20-30 hours compared to minutes for native IGF-1. The short version: people usually care about it for muscle protein synthesis, extended half-life igf-1, anabolic, but the strength of the evidence depends heavily on indication and study type.

IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified version of IGF-1 with an extended half-life of approximately 20-30 hours compared to minutes for native IGF-1. The modifications include an arginine substitution at position 3 and a 13-amino acid extension at the N-terminus, which reduce binding to IGF binding proteins (IGFBPs).

IGF-1 is a critical mediator of growth hormone's anabolic effects. While GH triggers IGF-1 production in the liver, IGF-1 LR3 provides direct IGF-1 receptor activation with enhanced potency and duration. It is one of the most potent anabolic research compounds available.

Research Snapshot

What the evidence says

Animal

IGF-1 LR3 currently shows 0 registered trials from ClinicalTrials.gov, 0 PubMed trial publications (0 RCT-tagged), and 10 PubMed references matching the stored source query. Treat PubMed references as literature surface area, not a count of clinical trials.

Known vs uncertain

Known signals

  • 0 registered trials are tracked from ClinicalTrials.gov intervention records.
  • 0 PubMed clinical-trial publications are indexed.
  • 0 PubMed randomized controlled trial publications are indexed.
  • 10 PubMed references are tracked separately from trial counts and can include animal, in-vitro, review, mechanism, or clinical records.

Open questions

  • Evidence strength may vary by indication, route, formulation, and population.
  • Public anecdotes can highlight interest or concern but do not establish clinical efficacy.
  • Regulatory status and compounding access can change independently from the research literature.

Mechanism of Action

IGF-1 LR3 binds to IGF-1 receptors throughout the body, activating the PI3K/Akt signaling pathway which promotes protein synthesis, cell proliferation, and anti-apoptotic signaling.

Key Research Benefits

Extended half-life (20-30 hours vs minutes for native IGF-1)
Potent stimulator of muscle protein synthesis
Studied for muscle growth and recovery
Activates satellite cells for muscle repair
Nutrient partitioning effects (directs nutrients toward muscle)

Clinical Evidence Summary

Research Pipeline

Preclinical
Animal
Phase I
Phase II
Phase III
Approved

0

Registered Trials

0

Trial Publications

0

RCT Publications

10

PubMed References

ClinicalTrials.govPubMed ESearchExact-name queryChecked May 3, 2026

Registered trials are ClinicalTrials.gov intervention records. Trial publications are PubMed records tagged as clinical trials or randomized controlled trials. PubMed references are broader source-query matches and can include animal studies, in-vitro work, reviews, mechanism papers, and trial publications.

0

Registered trials

0

Trial publications

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RCT publications

10

PubMed references

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Reviews

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Meta-analyses

Registered trials source

Jun 1, 2026

IGF-1 LR3

Uses the exact compound name as a ClinicalTrials.gov intervention query.

View source

Publication counts source

May 3, 2026

IGF-1 LR3

Uses the exact display name.

View source

Not FDA-approved. Research compound. Related to FDA-approved mecasermin (Increlex) which is recombinant IGF-1 for growth failure. WADA prohibited substance. High regulatory scrutiny.

Key PubMed References

Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice.

In Vitro

Engel MG, Narayan S, Cui MH, et al. · Journal of Alzheimer's disease : JAD · 2025

PMID: 39610283

Revolutionary decellularized Alstroemeria stem-based nerve conduit integrated with GelMA and controlled IGF-1 LR3 release for enhanced rat sciatic nerve regeneration.

Animal Study

Yavuz E, Sağır MS, Ercan A, et al. · International journal of biological macromolecules · 2025

PMID: 41015370

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep.

Review

White A, Stremming J, Wesolowski SR, et al. · American journal of physiology. Endocrinology and metabolism · 2025

PMID: 39679943

Attenuated glucose-stimulated insulin secretion during an acute IGF-1 LR3 infusion into fetal sheep does not persist in isolated islets.

Review

White A, Stremming J, Brown LD, et al. · Journal of developmental origins of health and disease · 2023

PMID: 37114757

Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris.

Review

Lu Z, Liu N, Huang H, et al. · Applied microbiology and biotechnology · 2023

PMID: 37261455

Anecdotes & Sentiment

Public discussion, not clinical evidence

This section summarizes what people are talking about in public sources. It can be useful for spotting questions, hype cycles, and recurring concerns, but it is separate from the evidence sections above.

No curated public-discussion themes are live for IGF-1 LR3 yet.

Side Effects & Safety

- Hypoglycemia (IGF-1 has insulin-like effects) - Joint pain and swelling - Potential organ growth with prolonged use - Theoretical cancer concerns (promotes cell proliferation) - Jaw and hand growth at high doses

Hypoglycemia (IGF-1 has insulin-like effects)
Joint pain and swelling
Potential organ growth with prolonged use
Theoretical cancer concerns (promotes cell proliferation)
Jaw and hand growth at high doses

Known Interactions

No curated interaction entry is live for IGF-1 LR3 yet.

Until the interaction table is fully populated, use the interaction checker and related peptides below to explore adjacent compounds and likely research pairings.

Comparison Pages

Comparison pages

All

No comparison page is linked yet.

Frequently Asked Questions

Research Disclaimer

This page is for research and educational purposes only. The information presented is based on published scientific literature and does not constitute medical advice, diagnosis, or treatment recommendations. Regulatory status can vary by compound, formulation, indication, and jurisdiction. Check official labeling, registry records, and qualified professional guidance before making any health-related decision. The studies referenced are linked to their original PubMed sources for verification.