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IGF-1 LR3
Growth Hormone / IGF-1 AxisPhase 2Also known as: IGF-1 Long R3
IGF-1 LR3 (Long R3 IGF-1) is a modified analog of insulin-like growth factor 1 featuring an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications reduce binding protein affinity by ~1000-fold compared to native IGF-1, increasing bioavailability and extending the half-life from minutes to hours..
Overview
Key Takeaways
- →Muscle hypertrophy
- →Recovery
- →Protein synthesis
- →Half-life: 20–30 hours (vs 12–15 minutes for native IGF-1)
At A Glance
IGF-1 LR3 binds the IGF-1 receptor (IGF1R), activating downstream PI3K/Akt and MAPK/ERK signaling pathways to stimulate cell proliferation, differentiation, and survival. The Long R3 modification prevents binding to IGF binding proteins (IGFBPs) that would normally sequester native IGF-1, resulting in a far higher proportion of free, bioavailable peptide. In skeletal muscle, IGF-1 signaling promotes satellite cell activation and protein synthesis via mTORC1.
IGF-1 LR3 binds the IGF-1 receptor (IGF1R), activating downstream PI3K/Akt and MAPK/ERK signaling pathways to stimulate cell proliferation, differentiation, and survival. The Long R3 modification prevents binding to IGF binding proteins (IGFBPs) that would normally sequester native IGF-1, resulting in a far higher proportion of free, bioavailable peptide. In skeletal muscle, IGF-1 signaling promotes satellite cell activation and protein synthesis via mTORC1.
Overview
IGF-1 LR3 (Long R3 IGF-1) is a modified analog of insulin-like growth factor 1 featuring an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications reduce binding protein affinity by ~1000-fold compared to native IGF-1, increasing bioavailability and extending the half-life from minutes to hours.
Potential Benefits
Potential Research Fields
Chemical Information
IUPAC Name
Insulin-like growth factor I, 7-70-peptide (synthetic) 1-[(2S)-2-amino-2-carboxyethyl] compound
CAS Number
946870-92-4
Molecular Formula
C400H625N111O115S9
Molecular Mass
9117.6 g/mol
Dosing & Protocols
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Research
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Interactions
Interaction Matrix
Contraindications
Cancer or history of cancer (growth-promoting properties). Hypoglycemia risk. Active diabetic retinopathy. Pregnancy or breastfeeding.
Research Disclaimer
This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds.
$49.99
up to $75.00
$49.9900
4
4
vial
Price History
2 data pointsRelated Compounds
View AllCJC-1295 (Mod GRF 1-29)
Growth Hormone / IGF-1 Axis
CJC-1295 without DAC (Modified GRF 1-29) is a synthetic 29-amino acid GHRH analog with four amino acid substitutions that extend its half-life from under 2 minutes to approximately 30 minutes.
CJC-1295 with DAC
Growth Hormone / IGF-1 Axis
CJC-1295 with DAC uses a Drug Affinity Complex linker (maleimidopropionic acid) that forms a permanent covalent bond with serum albumin after injection, extending the half-life to 6–8 days.
GHRP-2
Growth Hormone / IGF-1 Axis
GHRP-2 is a synthetic hexapeptide growth hormone-releasing peptide that potently stimulates GH release from the pituitary gland.
GHRP-6
Growth Hormone / IGF-1 Axis
GHRP-6 is a synthetic hexapeptide growth hormone secretagogue and one of the original GHRPs studied.
Hexarelin
Growth Hormone / IGF-1 Axis
Hexarelin is a synthetic hexapeptide growth hormone secretagogue that produces the most potent GH release of any GHRP.
Ipamorelin
Growth Hormone / IGF-1 Axis
Ipamorelin is a selective pentapeptide growth hormone secretagogue that mimics ghrelin at the GHSR-1a receptor with high selectivity.
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Protocols, calculator & safety for IGF-1 LR3
Research Score
40 PubMed studies
Quality Indicators
Data Completeness
100%COA Verification
10
Verified COAs
2
Vendors w/ COA
High verification rate (83%)
Latest test: 3/1/2026
Research Credibility
Quick Facts
Half-Life
20–30 hours (vs 12–15 minutes for native IGF-1)
Molecular Weight
9117.6 g/mol
Administration
Subcutaneous, Intramuscular
CAS Number
946870-92-4
Trial Phase
Phase 2
Safety Profile
Moderate RiskCommon Side Effects
- • Hypoglycemia (dose-dependent)
- • Jaw pain
- • Headache
- • Fatigue
Stop Use If
- Active malignancy — IGF-1 is mitogenic
- Diabetic retinopathy
- Severe hypoglycemia episodes
Research Disclaimer
This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.
Frequently Asked Questions
What is IGF-1 LR3 used for in research?
IGF-1 LR3 (Long R3 IGF-1) is a modified analog of insulin-like growth factor 1 featuring an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications reduce binding protein affinity by ~1000-fold compared to native IGF-1, increasing bioavailability and extending the half-life from minutes to hours.
What forms does IGF-1 LR3 come in?
IGF-1 LR3 is available in vial form.
How much does IGF-1 LR3 cost?
Prices start at $49.99 across 4 verified vendors.
How do I compare IGF-1 LR3 vendors?
Compare prices, payment methods, shipping, and COA scores across 4 vendors.
Research Tools
Related Compounds
View AllCJC-1295 (Mod GRF 1-29)
Growth Hormone / IGF-1 Axis
CJC-1295 without DAC (Modified GRF 1-29) is a synthetic 29-amino acid GHRH analog with four amino acid substitutions that extend its half-life from under 2 minutes to approximately 30 minutes.
CJC-1295 with DAC
Growth Hormone / IGF-1 Axis
CJC-1295 with DAC uses a Drug Affinity Complex linker (maleimidopropionic acid) that forms a permanent covalent bond with serum albumin after injection, extending the half-life to 6–8 days.
GHRP-2
Growth Hormone / IGF-1 Axis
GHRP-2 is a synthetic hexapeptide growth hormone-releasing peptide that potently stimulates GH release from the pituitary gland.
GHRP-6
Growth Hormone / IGF-1 Axis
GHRP-6 is a synthetic hexapeptide growth hormone secretagogue and one of the original GHRPs studied.
Hexarelin
Growth Hormone / IGF-1 Axis
Hexarelin is a synthetic hexapeptide growth hormone secretagogue that produces the most potent GH release of any GHRP.
Ipamorelin
Growth Hormone / IGF-1 Axis
Ipamorelin is a selective pentapeptide growth hormone secretagogue that mimics ghrelin at the GHSR-1a receptor with high selectivity.