IGF-1 LR3
Also known as: Long Arg3 IGF-1 · Insulin-like Growth Factor 1 LR3 · LR3-IGF-1
IGF-1 LR3 binds the IGF-1 receptor (IGF-1R) with high affinity, activating PI3K/Akt/mTOR signaling for protein synthesis and skeletal muscle hypertrophy. It also activates RAS/MAPK/ERK pathway for cellular proliferation. Unlike native IGF-1, the N-terminal Arg3 extension dramatically reduces binding to IGF...
What It Is
IGF-1 LR3 binds the IGF-1 receptor (IGF-1R) with high affinity, activating PI3K/Akt/mTOR signaling for protein synthesis and skeletal muscle hypertrophy. It also activates RAS/MAPK/ERK pathway for cellular proliferation. Unlike native IGF-1, the N-terminal Arg3 extension dramatically reduces binding to IGF binding proteins (IGFBPs), which sequester and inactivate native IGF-1. This results in a half-life of ~20 hours vs ~15 minutes for native IGF-1. IGF-1 LR3 activates satellite cell proliferation and differentiation for new muscle fiber formation, promotes glucose uptake independent of insulin, and has anti-apoptotic (cell survival) properties.
Supplies Needed
Reconstitution - acetic acid improves stability
Subcutaneous or intramuscular injection
Sterilization
Emergency hypoglycemia management
Storage
Store at -20C for up to 2 years. Extremely sensitive to heat - do not leave at room temperature for extended periods.
Refrigerate at 2-8C; use within 30 days. Avoid repeated freeze-thaw.
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.
Dosing Protocols
Timing: Post-workout (within 30 minutes of training). Start at 20 mcg to assess hypoglycemia risk; always have fast-acting carbohydrates available; strict 4-on/4-off cycling required to prevent receptor desensitization
↓ Apply these values to the reconstitution calculatorTiming: Post-workout; 50% systemic, 50% near target muscles for local hypertrophy. Classic bodybuilding protocol; eat within 30 minutes of injection to prevent hypoglycemia
↓ Apply these values to the reconstitution calculatorTiming: Post-workout, injected near trained muscle groups for local hypertrophy effect. High dose for maximum hypertrophy; hypoglycemia risk significant; require strict cycling and careful glucose monitoring
↓ Apply these values to the reconstitution calculatorWeekly Timeline
| Week | Expected Effects |
|---|---|
| Week 1 | Rapid increase in muscle fullness and pump; improved post-workout recovery; possible water retention |
| Week 2 | Noticeable lean mass gain; satellite cell activation beginning; improved strength |
| Week 4 | Peak anabolic effect - significant lean mass gain; potential new muscle fiber formation; must cycle off |
| Week 8 | (After 4 weeks off) Retained lean mass gains with receptor sensitivity restored; ready for next cycle |
Reconstitution Calculator
1 unit on U-100 syringe = 0.01 mL · Always label your vial after reconstitution
Injection Technique & Reconstitution
- Remove flip-top cap from the vial
- Swab rubber stopper with alcohol swab
- Draw 1 mL bacteriostatic water or 0.6% acetic acid into syringe
- Inject slowly down the vial wall - do not spray on powder
- Gently swirl until dissolved - do NOT shake
- Label with reconstitution date; refrigerate at 2-8C
- IGF-1 LR3 can also be diluted in 0.1% BSA solution for improved stability
Use our free dosing calculator to get the exact syringe units for your vial size and dose.
Mechanism of Action
IGF-1 LR3 binds the IGF-1 receptor (IGF-1R) with high affinity, activating PI3K/Akt/mTOR signaling for protein synthesis and skeletal muscle hypertrophy. It also activates RAS/MAPK/ERK pathway for cellular proliferation. Unlike native IGF-1, the N-terminal Arg3 extension dramatically reduces binding to IGF binding proteins (IGFBPs), which sequester and inactivate native IGF-1. This results in a half-life of ~20 hours vs ~15 minutes for native IGF-1. IGF-1 LR3 activates satellite cell proliferation and differentiation for new muscle fiber formation, promotes glucose uptake independent of insulin, and has anti-apoptotic (cell survival) properties.
Key Research Papers
Demonstrated significant activation of satellite cells and increased protein synthesis rates in skeletal muscle treated with IGF-1 LR3, establishing the anabolic mechanism.
View on PubMed →Stacks Well With
Synergistic muscle hypertrophy stack - IGF-1 LR3 activates global mTOR/protein synthesis while PEG-MGF specifically activates satellite cells for muscle fiber repair and regeneration. Stack post-workout.
GH secretagogue + downstream IGF-1 analog provides comprehensive anabolic signaling - GH pulse from Ipamorelin plus direct IGF-1R activation from IGF-1 LR3.
Frequently Asked Questions
IGF-1 LR3 is used for muscle hypertrophy, satellite cell activation for muscle fiber formation, improved recovery, and body recomposition. It binds IGF-1 receptors directly, activating mTOR-driven protein synthesis.
Native IGF-1 is almost completely bound by IGF binding proteins (IGFBPs) in the bloodstream, giving it a 15-minute half-life. The LR3 modification prevents IGFBP binding, extending the half-life to ~20 hours.
Yes - IGF-1 LR3 promotes glucose uptake via GLUT4 translocation (similar to insulin). Always eat a meal with carbohydrates within 30 minutes of injection and keep fast-acting carbohydrates available.
Legal Status by Region
This information is provided for educational and research purposes only. Not approved for human consumption by the FDA or any regulatory body. Always consult a qualified medical professional.