IGF-1 LR3 — Clinical Reference

**⚠ Educational reference only — not medical advice.** This article is for research and educational reference. Always consult your own physician before considering any peptide protocol. See the full Disclaimer at the end of this article. ## Introduction IGF-1 LR3 ("Long R3 IGF-1") is an 83-amino-acid analogue of insulin-like growth factor 1, modified by an arginine substitution at position 3 and an N-terminal 13-amino-acid extension. These modifications drastically reduce binding to IGF-binding proteins (IGFBPs), extending free-fraction circulation and biological half-life. Investigational; not FDA-approved. ## Mechanism of Action Binds the type-1 IGF receptor (IGF1R), a transmembrane tyrosine kinase. Receptor activation drives the PI3K/Akt and MAPK pathways, promoting protein synthesis, cellular proliferation, and inhibition of apoptosis. Reduced IGFBP binding leaves a higher proportion of the molecule bioavailable to the receptor. ## Research Indications Sarcopenia, tendinopathy, post-injury recovery, and conditions characterized by anabolic deficit. No approved clinical indication. ## Reconstitution Typical 1 mg lyophilized vial: add **1 mL of bacteriostatic water**, swirl gently. Final concentration **1000 mcg/mL (1 mg/mL)** — each 0.02 mL (2 units on a U-100 insulin syringe) delivers 20 mcg. ## Dosing Protocol (research literature) Research protocols typically dose **20–50 mcg subcutaneously once daily**, often timed **post-workout** to align with anabolic-window protocols. Cycle length **4–6 weeks**, followed by an equal off-period (IGF1R downregulation occurs with continuous use). Some local-injection protocols use 20–40 mcg into the area of tendinopathy. ## Administration Subcutaneous into abdominal fat (systemic) or local injection (tendinopathy protocols). **Eat within 30 minutes of administration** to mitigate hypoglycemia risk. ## Storage & Handling Lyophilized: refrigerate (2–8°C). Reconstituted: refrigerate; stable approximately **14–21 days**. Protect from light. Do not freeze reconstituted product. ## Side Effects Most concerning is **hypoglycemia** — IGF1R activation produces insulin-mimetic effects, particularly with concurrent insulin/sulfonylurea or under-eating. Other risks: arthralgia, peripheral edema, hypothetical concerns regarding proliferation of any active malignancy or proliferative diabetic retinopathy. ## Contraindications Active or recent malignancy, untreated proliferative retinopathy, pregnancy, lactation, uncontrolled diabetes. ## Monitoring Baseline fasting glucose, HbA1c, lipid panel, comprehensive metabolic panel, dilated retinal exam where applicable. Continuous-glucose monitoring is prudent in research protocols. Counsel patients to recognize hypoglycemic symptoms and to eat within 30 minutes of administration. ## Disclaimer **This article is for informational and research-reference purposes only.** Nothing in this document constitutes medical advice, a prescription, or a recommendation from a physician. The reconstitution, dosing, and protocol information above reflects ranges commonly cited in published research and clinician-directed protocols — it is provided as reference material only, not as instructions, an endorsement of off-label use, or a substitute for individualized medical evaluation. **Customers should do their own research and consult their own physician** before considering any peptide protocol. Whether a given compound is appropriate for an individual — and at what dose, for what duration, and alongside what monitoring — is a decision that only a licensed clinician with knowledge of that individual's medical history, current medications, and conditions can make. The platform and the author make no claim that any compound described here is safe, effective, or appropriate for any particular person or purpose, and accept no responsibility for outcomes arising from self-directed use of the information.