IGF-1 LR3
IGF-1 LR3 (Long R3 Insulin-Like Growth Factor 1)
A long-acting synthetic analogue of IGF-1 with dramatically extended half-life, used in muscle research for satellite cell activation and protein synthesis.
IGF-1 LR3 is not approved by the FDA for human use. It is sold strictly for research purposes only and is not intended for human consumption, diagnosis, treatment, or prevention of any disease or condition. Purchase and use is entirely at your own risk.
Sourcing for research purposes?
View at Ascension Peptides →What it is
IGF-1 LR3 is a synthetic analogue of endogenous IGF-1 (Insulin-Like Growth Factor 1) with two modifications: an arginine substitution at position 3 and an added 13-amino acid extension at the N-terminus. These changes prevent binding to IGF-binding proteins (IGFBPs), dramatically extending its half-life compared to native IGF-1.
Endogenous IGF-1 has a half-life of 12–15 minutes in circulation. IGF-1 LR3 extends this to approximately 20–30 hours, giving it sustained anabolic signaling capacity.
What research shows
- Activation of muscle satellite cells — the precursor cells to new muscle fiber formation
- Enhanced protein synthesis and nitrogen retention in muscle tissue
- Does not bind IGFBPs — more bioavailable than endogenous IGF-1
- Significant hypoglycemia risk — shares signaling pathways with insulin
- Used extensively in muscle biology research to study hypertrophy mechanisms
What remains unknown
- Safe dosing windows in humans — hypoglycemia risk requires careful titration
- Long-term safety profile, particularly related to cell proliferation
- Net effect on cancer risk with chronic use (IGF-1 is growth-promoting)
- Whether observed muscle effects in research translate to meaningful real-world outcomes
Administration basics
Common use cases
Muscle hypertrophy research, recovery from muscle injuries. Carries significant risk profile.
Half-life
~20–30 hours.
Administration
Subcutaneous or intramuscular injection. Blood glucose monitoring is strongly advised.
Source this compound
Looking for IGF-1 LR3?
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View at Ascension PeptidesResearch Protocols & Common Usage
Doses used in research
- Research has studied doses of 40–100mcg/day in animal and cell models
- Community protocols commonly report 20–60mcg/day for short periods
Administration routes studied
Typical protocol duration
Short cycles of 4–6 weeks are commonly reported in community use due to concerns about receptor desensitization.
Common stacking protocols
- IGF-1 LR3 + Ipamorelin/CJC-1295 — combined for GH and IGF-1 pathway synergy
- IGF-1 LR3 + BPC-157 — combined in some recovery and muscle repair protocols
- IGF-1 LR3 + MGF — MGF for satellite cell activation followed by IGF-1 LR3 for proliferation
Contraindications & combinations to avoid
- Hypoglycemia risk — IGF-1 LR3 has significant blood-glucose-lowering effects; never combine with insulin without careful medical oversight
- Active cancer or cancer history — IGF-1 is a potent mitogen implicated in multiple cancer types
- Diabetes — significant glucose regulation effects
Dosing information reflects doses used in published research and commonly reported community protocols only. This is not a personal recommendation. These compounds are not FDA-approved for human use in the contexts described. Consult a qualified healthcare provider before starting any protocol.
Considering stacking?
See the stacking guide for common combinations with IGF-1 LR3 and what to avoid.
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Community Reviews
Reviews reflect individual user experiences with research compounds and are not medical advice. Results vary. These compounds are not FDA approved for human use. Peptelligent does not verify reported experiences.
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