IGF-1 LR3 (2mg)
IGF-1 LR3 (Long R3 Insulin-like Growth Factor-1) is a modified analogue of human IGF-1 with a significantly prolonged half-life (~20–30 hours) due to reduced binding to IGFBPs. 2mg Vial — reconstitution with 2 mL of 0.6% acetic acid yields 1 mg/mL (1 unit = 10 mcg).
Reviewed by the AllPeptides.eu Editorial Team·Last reviewed: 2026-06-16
Educational information. Not medical advice, and no efficacy claim is implied. Regulatory approval is not a use recommendation by AllPeptides.eu.
⚠️ For informational/educational purposes only. Not medical advice. We do not sell any products. Self-treatment carries serious risks — consult a healthcare professional. Disclaimer
How It Works
IGF-1 LR3 is a synthetic analogue of human IGF-1 with an N-terminal 13-amino acid extension and a Glu→Arg substitution at position 3 (Long R3). These modifications drastically reduce its affinity for IGF-binding proteins (IGFBPs), extending its half-life from minutes (native IGF-1) to several hours. The prolonged circulation time allows for once-daily dosing protocols. It activates PI3K/Akt/mTOR and MAPK/ERK pathways via the IGF-1R receptor, enhancing protein synthesis and insulin-like metabolic effects (requires blood glucose monitoring).
Quick Start
- Reconstitution: 2.0 mL 0.6% acetic acid → 1 mg/mL. ⚠️ Acetic acid only — BAC water does not properly dissolve IGF-1 LR3.
- Typical Daily Range: 20–50 mcg once daily subcutaneously.
- Storage: Lyophilized: −20 °C; Reconstituted: 2–8 °C, use within 30 days.
Typical / Step-Up Approach (2 mL = 1 mg/mL)
Route: Subcutaneous | Frequency: Once daily
| Week | Dose | Units (per injection) |
|---|---|---|
| Weeks 1–2 | 20 mcg (0.02 mg) | 2 Units (0.02 mL) |
| Weeks 3–4 | 40 mcg (0.04 mg) | 4 Units (0.04 mL) |
| Weeks 5–8 | 50 mcg (0.05 mg) | 5 Units (0.05 mL) |
Studies report administration once daily subcutaneously, typically in the morning or after exercise, with a meal to mitigate hypoglycemia.
Related compounds
Reconstitution Steps
- ⚠️ Use 0.6% acetic acid exclusively — NOT bacteriostatic water.
- Draw 2.0 mL of 0.6% acetic acid with a sterile syringe.
- Inject slowly onto the vial wall — avoid foaming; do not shake.
- Gently roll until fully dissolved (2–3 minutes).
- Label with date and refrigerate at 2–8 °C, protected from light.
- Use within 30 days; for long-term storage, aliquot and freeze at −20 °C.
Protocol Overview
- Goal: Support anabolic processes via prolonged IGF-1 action.
- Schedule: Daily subcutaneous injections × 8 weeks (typical cycle).
- Cycling: 8 weeks on, 4–8 weeks off to prevent desensitization.
Dosing Protocol
- Initiation (Wks 1–2): 20 mcg daily — assess glucose impact.
- Titration (Wks 3–4): 40 mcg daily if tolerated.
- Maintenance (Wks 5–8): 50 mcg daily — conservative upper limit.
- Frequency: 1×/day subcutaneous; timing with meals.
- Duration: 8 weeks; extension to 12 possible with diminishing returns.
- Break between cycles: After cycle (8 weeks), cease use for 4–8 weeks to prevent IGF-1R desensitization.
Washout & Cycle Restart
When can I restart?
After cycle (8 weeks), cease use for 4–8 weeks to prevent IGF-1R desensitization.
Minimum wait period: 4 weeks
Storage Instructions
- Lyophilized: Store at −20 °C (−80 °C optimal), up to 12 months.
- Reconstituted: Refrigerate at 2–8 °C — use within 30 days.
- Long-term storage: Aliquot and freeze at −20 °C, stable for 3–6 months.
- Never refreeze a thawed solution.
- Check for clarity before use — discard if cloudy.
Important Notes
- Hypoglycemia awareness: Have fast-acting carbohydrates readily available.
- Meal timing: Administer with or immediately after food intake.
- Do not exceed 50–60 mcg/day — higher doses lack clinical substantiation.
Potential Benefits & Side Effects
Potential Benefits:
- Enhanced anabolic signaling and protein synthesis.
- Prolonged bioavailability vs. native IGF-1.
- Metabolic effects via IGF-1R.
Potential Side Effects:
- Hypoglycemia risk — the most significant concern; take with food.
- Mild injection site reactions.
- Dose-dependent concerns >50–60 mcg/day.
- Receptor desensitization with continuous use >6–8 weeks.
⚠️ Serious Warnings & Long-Term Risks
The following warnings are based on published literature, FDA labels, and post-marketing surveillance. They do not constitute medical advice. Consult a healthcare professional.
Increased neoplasia risk
IGF-1 is a potent mitogenic factor. The LR3 variant has 3× longer half-life, amplifying risk. Contraindicated in active or history of neoplasia.
📄 Endocrine Reviews 2009Hypoglycemia & cardiovascular risk
IGF-1 LR3 can cause severe hypoglycemia. Chronic use may lead to cardiac hypertrophy.
📄 FDA Label — Increlex® (IGF-1 base)References
- Biomolecules (MDPI) — IGF-1: Monitoring in Medicine and Sports
View Source - Dopinglinkki (FINCIS) — IGF-1 and LR3IGF-1: Safety Information
View Source - Mayo Clinic — Mecasermin — Proper Use and Meal Timing
View Source - Cell Sciences — rhLR3 IGF-1 — Technical Storage and Stability Specifications
View Source - Frontiers in Bioengineering — IGF-1: A Therapeutic Target for Peripheral Nerve Injury
View Source
Recommended Supplements
L-Arginine + L-Ornithine
ZMA (Zinc + Magnesium + B6)
External Sources & Regulatory Status
Regulatory Approvals
Increlex® (IGF-1 base) · IGF-1 deficiency (children) (2005)
IGF-1 base FDA approved (LR3 variant research-only)
Educational information. Not medical advice, and no efficacy claim is implied. Regulatory approval is not a use recommendation by AllPeptides.eu.
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