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Research onlyGrowth hormoneSubcutaneousEvidence 2/5

IGF-1 LR3

Also known as: Long R3 IGF-1

A modified IGF-1 that binds IGF binding proteins far more weakly than native IGF-1, leaving it free to act as a potent, long-acting agonist at the IGF-1 receptor.

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IGF-1 LR3
Drug class
IGF-1 analog / IGF-1 receptor agonist (research reagent)
Primary targets
IGF-1R
Dose reference
No validated human dose; research reagent only
Half-life
~20-30 hours (reported, non-clinical estimate)
Developer / origin
GroPep Ltd (Adelaide, Australia)
Reference year
1992
Evidence score
2/5 - Preclinical / reagent only
Evidence 2/5

Preclinical / reagent only

IGF-1 LR3 is well characterized as a cell-culture supplement and in animal infusion studies, but there is essentially no controlled human therapeutic data.

Mostly animal, ex vivo, cell, or indirect evidence.

Evidence basis

  • Reduced IGFBP affinity with retained IGF-1R binding
  • Validated potency in serum-free cell culture
  • Animal infusion studies showing disproportionate organ growth
  • No published controlled human therapeutic trials

How to read this entry

Dose references and half-life values are pulled from trial protocols, labels, reviews, or published summaries where available. They are context for research and comparison, not a personal dosing recommendation.

Status matters: approved drugs have regulated indications; investigational compounds are still being studied; research-only peptides do not have established human dosing, safety, or efficacy for consumer use.

IGF-1 LR3 guides

Read the matching guide or adjacent research pages for more context.

IGF-1 LR3 Peptide: Long R3 IGF-1 Research Facts and SafetyIGF-1 LR3 is a modified IGF-1 analogue built as a research reagent. Its reduced IGFBP binding raises potency in the lab, but human therapeutic data is essentially absent.Sermorelin: What the GHRH Analog Does — and What It Doesn'tSermorelin is a GHRH (growth-hormone-releasing hormone) analog — not a GLP-1, despite being searched alongside them. What it does to growth hormone, and where it stands legally.GHRP-2 Peptide: Pralmorelin, GH Secretagogue Science and SafetyGHRP-2, or pralmorelin, is a ghrelin-receptor growth hormone secretagogue approved in Japan only as a GH-deficiency diagnostic, not as a consumer therapeutic.HGH Fragment 176-191 Peptide: Lipolysis Claims and Honest EvidenceHGH Fragment 176-191 is the C-terminal lipolytic fragment of growth hormone with animal data, but no convincing human fat-loss evidence.

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Research & educational purposes only

The information on PeptideStat is for educational and research purposes only and is not medical advice. Many peptides discussed are research compounds not approved for human use. Always consult a qualified healthcare professional before making any health decisions. Articles may contain affiliate links — we may earn a commission at no extra cost to you.