IGF-1 LR3
Long R3 Insulin-like Growth Factor-1
Long-acting IGF-1 that bypasses the binding proteins
An engineered analog of IGF-1 with an extended half-life and a substitution that prevents it from being bound and inactivated by IGF binding proteins. The result is a far more potent, longer-lasting signal at the IGF-1 receptor — driving the anabolic and hyperplasic effects that sit downstream of growth hormone.
- Half-life
- ~20–30 hours
- Route
- Subcutaneous injection
- Typical dose
- 20–50 mcg/day
- Availability
- Research-only
Key Benefits
Direct, long-acting IGF-1 receptor stimulation
Drives protein synthesis and muscle growth
Supports satellite-cell proliferation (hyperplasia)
Faster recovery and tissue repair
Active far longer than native IGF-1
Mechanism of Action
How IGF-1 LR3 works
IGF-1 LR3 acts directly at the IGF-1 receptor, downstream of the GH axis:
- IGF-1 receptor (IGF1R) activation — binds and activates IGF1R on muscle and other tissue, triggering the PI3K/Akt/mTOR anabolic cascade that drives protein synthesis and cell growth.
- Resistance to binding proteins — the R3 substitution sharply lowers affinity for IGFBP-3, so far more peptide stays free and active compared with native IGF-1, extending the half-life from minutes to hours.
- Hyperplasia signaling — unlike GH alone, IGF-1 can drive satellite-cell proliferation (new muscle nuclei), the basis for its reputation as a hyperplasic agent.
- Glucose handling caution — IGF1R shares signaling with the insulin receptor, so IGF-1 LR3 can lower blood glucose; genetics and dosing both matter here.
Your Genetics & IGF-1 LR3
Genetic variants that affect your response
These SNPs determine how effectively IGF-1 LR3 works for you specifically. A genetic peptide report identifies your variants before you start.
This promoter variant sets your baseline circulating IGF-1. Low-expressers start from a lower IGF-1 set point and may notice a larger relative effect from supplemental IGF-1 LR3.
Variants in the IGF-1 receptor gene change receptor signaling efficiency — the direct target of IGF-1 LR3. Receptor-sensitivity differences shape how strongly the anabolic cascade fires at a given dose.
The -202 A/C variant sets IGFBP-3 levels. Although LR3 largely evades IGFBP-3, your binding-protein status still influences the native IGF-1 balance and overall IGF tone alongside the analog.
The GHR d3 polymorphism governs how efficiently GH is converted to IGF-1 upstream. It shapes your endogenous IGF-1 baseline and how IGF-1 LR3 layers on top of it.
Which variants do you carry?
Upload your DNA data or order a kit to find out.
Evidence & Research
35+
Published studies
Published human or robust animal studies with clear mechanistic rationale
Sourcing & access
Where to buy IGF-1 LR3
IGF-1 LR3 is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Swiss Chems is a US research-chemical supplier that publishes third-party Certificates of Analysis. Sold for research use only — check your local laws.
Before you buy: see whether your DNA actually responds to IGF-1 LR3, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you), and providers we partner with are listed first. Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Common Stacks
IGF-1 LR3 is commonly combined with:
CJC-1295
GH/IGF Axis StackModerate EvidenceCJC-1295 (Modified GRF 1-29)
A 29-amino-acid growth hormone releasing hormone (GHRH) analog with enhanced stability. CJC-1295 extends the duration of natural GH pulses without disrupting pulsatile release patterns, providing sustained elevation of growth hormone and IGF-1 for recovery, body composition, and anti-aging.
4
Gene variants
30+
Studies
BPC-157
Recovery StackModerate EvidenceBody Protection Compound 157
A 15-amino-acid peptide derived from human gastric juice. The most-researched peptide for tissue repair, gut healing, and injury recovery. Works through nitric oxide signaling, angiogenesis, and collagen stimulation.
4
Gene variants
100+
Studies
Follistatin-344
Muscle StackEmerging EvidenceFollistatin-344 (FST-344)
A naturally occurring protein that binds and neutralizes myostatin and activin — the body's built-in limiters on muscle growth. By sequestering myostatin, Follistatin-344 removes a key brake on hypertrophy, which is why it's one of the most discussed (and still early-stage) research peptides for muscle and recovery.
4
Gene variants
20+
Studies
Frequently Asked Questions
What is the difference between IGF-1 LR3 and regular IGF-1?
IGF-1 LR3 is an engineered analog with an extended half-life and a substitution that stops IGF binding proteins from inactivating it. Native IGF-1 lasts only minutes and is mostly bound; LR3 stays free and active for hours, making it far more potent for sustained IGF-1 receptor signaling.
Why does IGF-1 LR3 affect blood sugar?
The IGF-1 receptor shares signaling machinery with the insulin receptor, so activating it can lower blood glucose. This is why IGF-1 LR3 is dosed carefully and often timed around food. Your insulin- and IGF-pathway genetics influence how pronounced the glucose effect is.
Does genetics affect IGF-1 LR3 response?
Yes. IGF1 promoter variants set your baseline IGF-1, IGF1R variants determine receptor sensitivity to the analog, IGFBP3 status shapes the binding-protein balance, and the GHR d3 polymorphism governs upstream GH-to-IGF conversion. A genetic peptide report profiles these for safer, more effective dosing.
Learn More About IGF-1 LR3
Your next move
Two ways forward with IGF-1 LR3.
Not sure it's for you?
Will IGF-1 LR3 work for your genes — and at what dose?
Your report scores IGF-1 LR3 against your receptor, CYP and pathway variants — likely responder, non-responder, and a sensible starting dose — in minutes.
Analyze my DNA — $99Already decided?
Get IGF-1 LR3 from Swiss Chems.
A US research-chemical supplier with third-party Certificates of Analysis. Sold for research use only — check your local laws before ordering.
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