Research-grade compound. Laboratory use only. Not intended for human or animal use, ingestion, or injection. No medical claims are made or implied.
≥98% PurityIn-House HPLC & MS Tested
Growth FactorsSKU: CP-IGF
IGF-1LR3
≥99% PurityHPLC & MS verified
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IGF-1 LR3 (Long Arg3 IGF-1) is an 83-amino acid analog of insulin-like growth factor 1 with an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications significantly reduce IGF binding protein affinity, increasing bioavailability in research applications. Extended analog of IGF-1 with enhanced bioavailability Muscle hypertrophy and tissue growth studies IGF-1 signaling pathway and receptor activation research For research purposes only.
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| 1 unit | €17.99 | €17.99 | -- |
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| 10+ | €15.29 | €152.91 | 15% off |
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Important Notice
This product is intended for laboratory and research use only. Not for human or veterinary use. By purchasing, you confirm this product will be used exclusively for in-vitro research purposes.
When This Product May Not Suit Your Research
- ⚠If your research requires GMP-grade material for clinical applications — research-grade peptides are not intended for clinical use.
- ⚠If your lab lacks proper cold storage (-20°C freezer) — this peptide's stability may be compromised at higher temperatures.
- ⚠If your study protocol requires FDA-approved reference standards — contact USP or a certified reference material provider.
Purity HPLC
99.3% average HPLC purity, verified by independent third-party testing
Third-Party Tested
Janoshik report published when available
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Last reviewed: 2026-04-24
About IGF-1LR3
IGF-1 LR3 (Long R3 IGF-1) is a recombinant analogue of insulin-like growth factor 1 engineered for extended half-life. The modifications consist of two changes from native IGF-1: a 13-amino acid N-terminal extension and an arginine substitution at position 3. Together these modifications reduce binding to IGF binding proteins (IGFBPs), which in the native system sequester IGF-1 and limit its bioavailability. The result is approximately 10-15 times longer half-life than native IGF-1 and substantially higher bioavailability due to reduced IGFBP binding.
IGF-1 is the primary mediator of growth hormone's anabolic effects. After GH stimulates hepatic IGF-1 production, circulating IGF-1 binds IGF-1 receptors in muscle, bone, and other tissues to drive protein synthesis, cell proliferation, and differentiation. IGF-1 receptor signaling activates PI3K/Akt and MAPK pathways -- core regulators of cell growth and survival. In skeletal muscle specifically, IGF-1 signaling promotes muscle protein synthesis, satellite cell activation, and hypertrophy. IGF-1 LR3's extended activity makes it useful for studying IGF-1 receptor biology over longer time windows than native IGF-1 allows.
One caveat worth noting for research design: the reduced IGFBP binding means IGF-1 LR3 behaves differently from endogenous IGF-1 in systems where binding proteins play a physiological role. Studies examining IGFBP-IGF interactions or physiological IGF-1 signaling should account for this difference.
Specifications
| Parameter | Value |
|---|---|
| Compound | IGF-1 LR3 (Long Arg3 IGF-1) |
| Purity | 99.3% avg (HPLC verified) |
| Format | Lyophilized powder |
| Reconstitution | 0.1% acetic acid or bacteriostatic water |
| Storage | -20°C; 2-8°C after reconstitution |
Storage
Store at -20°C before reconstitution. Reconstitute with 0.1% acetic acid initially, then dilute with PBS or cell culture medium. Refrigerate reconstituted solutions at 2-8°C and use within 7-14 days. Avoid repeated freeze-thaw cycles.
What does "LR3" mean and how does it differ from native IGF-1?
LR3 stands for "Long R3" -- the L refers to a 13-amino acid N-terminal extension, and R3 refers to an arginine substitution at position 3 (replacing glutamate). Together, these changes reduce the affinity of IGF-1 LR3 for IGF binding proteins by approximately 1,000-fold compared to native IGF-1. Since IGFBPs sequester native IGF-1 and limit its bioavailability, this modification dramatically increases free IGF-1 concentration at receptors. The extended N-terminus also slows proteolytic clearance. Combined effect: approximately 10-15x longer half-life and much greater biological potency per mg administered.
What are the key differences between IGF-1 and HGH for muscle research?
HGH primarily works indirectly on muscle by stimulating hepatic IGF-1 production (endocrine signaling). IGF-1 also acts through autocrine/paracrine mechanisms locally in muscle tissue, where it's produced in response to loading. IGF-1 LR3 bypasses the GH-liver-IGF-1 axis and delivers IGF-1 receptor stimulation directly. This is useful for studies that want to examine IGF-1 receptor signaling independently of GH, or for studies where the GH-liver step would be a confounding variable. IGF-1 LR3 also has direct effects on satellite cell activation, complementing GH's role in the growth axis.
What research contexts require IGF-1 LR3 rather than native IGF-1?
IGF-1 LR3 is preferred when extended IGF-1 receptor stimulation is needed -- for chronic experiments, for systemic administration where rapid clearance of native IGF-1 would limit exposure, or for cell culture studies where the extended half-life provides more consistent receptor activation over the experiment duration. Native IGF-1 is preferred when studying the physiological IGFBP regulatory system or when IGFBP interactions are part of the research question, since LR3's reduced IGFBP binding removes a layer of regulation that may be important for certain studies.
IGF-1 LR3 is supplied for laboratory research use only. Not approved for human use. Handle in compliance with institutional biosafety guidelines.
Specification Summary
Purity99.3% avg
FormLyophilized Powder
Storage-20\u00B0C
Researcher Confidence
Why researchers choose CertaPeptides
Who actually tests this?
Every batch is independently verified by Janoshik Analytical (100,000+ verifications/month), Eurofins Scientific, and Analytical Sciences International. We publish every Certificate of Analysis.
View COAs →What if I get the wrong batch?
Every bottle label carries a lot number that maps to a specific Certificate of Analysis. If a batch fails spec, we don't ship it — full stop.
View COAs →Where does it ship from?
Romania (EU). We are CERTALAB SRL, CUI RO54451735, VAT-registered. SameDay for Romania, FanCourier for Central/Eastern EU, TCE Worldwide for the rest. 3–7 business days EU-wide.
Shipping details →What if there's a problem?
You have a 14-day withdrawal right under OUG 34/2014 (Romanian/EU consumer law), with ANPC/ODR escalation available. Contact us at support@certapeptides.com.
Returns policy →Product Information
This product is intended for scientific research and development purposes only. It is a chemical substance that shall not be used as a drug, medicine, active substance, or ingredient in any product intended for human or animal consumption. Researchers must handle this compound in accordance with their institutional biosafety guidelines. Use only in properly equipped laboratory settings with appropriate personal protective equipment.
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