IGF-1 LR3
A powerful anabolic peptide for lean muscle growth and enhanced recovery. IGF-1 LR3 is a modified version of insulin-like growth factor 1 with an extended half-life (~20-30 hours vs minutes). The modifications make it more potent for muscle protein synthesis and less affected by IGF binding proteins. Used in research for muscle growth and recovery.
Compare Prices🧬Key Characteristics
- Length: 83 amino acids(Native IGF-1 (70 AA) + 13 AA extension.)
- Half-life: 20-30 hours(vs. minutes for native IGF-1.)
- Binding: Reduced IGFBP(Less affected by binding proteins.)
- Primary Use: Muscle growth(Direct anabolic effects.)
Overview
Core Benefits
Key AdvantagesThese are educational summaries of commonly discussed effects in wellness/regenerative contexts, not guarantees.
IGF-1 LR3 Results Timeline
ProgressionTimeline is illustrative and non-guaranteed. Outcomes vary and are commonly discussed alongside training, nutrition, sleep, and cycling practices.
How It Works
Growth Factor — Long-Acting IGF-1 AnalogReceptor → Growth Cascade → Anabolic Signaling → Outcomes
IGF-1 Receptor (IGF-1R) — Direct Activation
Unlike GH peptides that indirectly raise IGF-1 by stimulating GH release, IGF-1 LR3 directly activates IGF-1 receptors. The LR3 modification (Arg→Glu at position 3 + 13-AA extension) reduces binding to IGF binding proteins, keeping it active ~3x longer than native IGF-1.
PI3K/Akt + MAPK → Protein Synthesis + Cell Proliferation
Direct IGF-1R activation triggers two major cascades: PI3K/Akt (protein synthesis, anti-apoptosis) and MAPK/ERK (cell proliferation, differentiation). This is the terminal growth signal that GH peptides ultimately produce, but IGF-1 LR3 bypasses the GH intermediate entirely.
Direct Anabolic Signaling → Muscle Hypertrophy
Potent anabolic effects: increased protein synthesis, muscle cell proliferation (hyperplasia — new fibers, not just bigger ones), nutrient partitioning toward muscle. Also lowers blood sugar by driving glucose into muscle cells — monitor blood sugar carefully.
Muscle Fullness → Rapid Recovery → Hypoglycemia Risk
Noticeable muscle fullness and pump within days. Accelerated recovery between sessions. Risk of hypoglycemia (low blood sugar) is real and requires careful monitoring. This is a potent compound — not for beginners.
What Makes This Peptide Different
IGF-1 LR3 is unique in bypassing GH entirely to directly activate growth signaling. While CJC-1295 and Ipamorelin stimulate GH → IGF-1 naturally, IGF-1 LR3 delivers the end-product directly. This makes it more potent but also more risky — it affects blood sugar, doesn't have the natural feedback loops of GH peptides, and requires careful dosing and monitoring.
Dosing Protocol
Muscle BuildingEducational reference only. Individual responses vary. Consult healthcare provider before use.
Why This Dosing Protocol
Why post-workout? Muscle tissue is most receptive to IGF-1 signaling after training. Post-workout intramuscular injection targets growth to trained muscles.
Why 10 days on, 4 weeks off? IGF-1R can desensitize with continuous exposure. Short cycles preserve receptor sensitivity. The 4-week off period allows full receptor recovery.
Why monitor blood sugar? IGF-1 LR3 drives glucose into cells, which can cause hypoglycemia. Have fast-acting carbs available, especially during initial use.
Diagrams
Hover for preview • Click to open full size
IGF-1 LR3 Pricing
We surface in-stock offers first and normalize by price per mg for quick comparisons.
1 mg / vial
In-stock offersLooking for medical guidance?
Join the waitlist for doctor-guided peptide plans. We'll notify you when telehealth consultations are available in your state.
Reconstitution calculator
Dilution math and unit conversions. Prefilled using a common vial size for this peptide.
Open calculatorEducational Videos
How to Reconstitute Peptides
Handling
Educational overview on storage, labeling, and traceability considerations for lab environments. Consult primary literature and vendor documentation for specifics.
- Freezer (-20°C): 1+ year ✓
- Refrigerator (2-8°C): 1-3 months ✓
- Room temperature: 2-3 weeks (emergency only)
- MUST refrigerate at 2-8°C
- 4-week maximum shelf life
- NEVER freeze after reconstitution
- Use bacteriostatic water for multi-dose
Storage & Handling Guide
Learn proper storage temperatures, shelf life timelines, reconstitution best practices, and travel tips for lyophilized and reconstituted peptides.
FAQ
What makes IGF-1 LR3 different from regular IGF-1?
IGF-1 LR3 has an arginine substitution and a 13-amino acid extension that makes it less affected by IGF binding proteins. This extends its half-life from minutes to 20-30 hours and increases its potency for muscle protein synthesis compared to native IGF-1.
How does IGF-1 LR3 relate to growth hormone?
IGF-1 is the downstream mediator of many GH effects. When GH stimulates the liver, it produces IGF-1. IGF-1 LR3 bypasses this pathway, directly providing IGF-1 activity. It's more targeted for muscle growth but lacks the broader metabolic effects of GH itself.
What does IGF-1 LR3 do for muscle growth?
IGF-1 LR3 promotes muscle growth through multiple mechanisms: increasing protein synthesis, enhancing nitrogen retention, promoting satellite cell activation (muscle cell precursors), and potentially causing muscle hyperplasia (new muscle cell formation). It's one of the most potent peptides for anabolic effects.
What is the typical IGF-1 LR3 dosage?
A common research dosage is 50 mcg per day (5 units on 1ml syringe), administered in the AM. Protocol: 10 days in a row, then 4 weeks off. Keep cycles short due to receptor desensitization concerns. Monitor blood sugar.
What are the side effects of IGF-1 LR3?
Potential side effects include hypoglycemia (low blood sugar), joint pain, water retention, and gut growth with prolonged high-dose use. Some report headaches and lethargy. Because IGF-1 promotes cell growth broadly, there are theoretical concerns about tumor promotion, though evidence is limited.
Does IGF-1 LR3 cause hypoglycemia?
Yes, IGF-1 LR3 can cause hypoglycemia because IGF-1 has insulin-like effects on glucose uptake. This is why it's often taken with food or post-workout when glucose is being utilized. Users should monitor for symptoms like shakiness, sweating, and confusion.
Can IGF-1 LR3 be combined with GH peptides?
Yes, some combine IGF-1 LR3 with GH-releasing peptides, though this is considered an advanced approach. The theory is that GH peptides provide broader benefits while IGF-1 LR3 adds targeted anabolic effects. However, this increases complexity and potential side effects.
Why are IGF-1 LR3 cycles kept short?
Extended IGF-1 LR3 use can cause receptor desensitization, reducing effectiveness. It may also cause unwanted growth of organs (particularly intestines) and other tissues with prolonged high-dose use. Most protocols limit cycles to 4-6 weeks with equal time off between cycles.
How long does reconstituted peptide last?
Once mixed with bacteriostatic water, peptides remain stable for up to 4 weeks when refrigerated at 2-8°C (36-46°F). Unopened powder can last 1+ year in the freezer. Get our complete Storage & Travel Guide.
Is this peptide legal to purchase?
Peptides sold "for research purposes only" are legal to purchase in the US, but are not FDA-approved for human use outside of specific medical applications. Always consult a healthcare provider before use.
New to peptides?
Take our Peptide Match tool to find the best peptide for your goals. You can also read our Complete Guide to Peptides to learn the basics.
Scientific Sources
The following peer-reviewed studies and official resources provide additional scientific context for this peptide:
Disclosure: we may earn affiliate commission from qualifying purchases. Educational information only — not medical advice.