IGF-1 LR3 Dosage Guide

IGF-1 LR3 is a synthetic, modified form of insulin-like growth factor 1 (IGF-1) that has been engineered with an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications reduce binding to IGF-binding proteins (IGFBPs), resulting in a significantly longer half-life (20–30 hours vs. ~15 minutes for native IGF-1) and approximately 3x greater potency.

IGF-1 is a key mediator of growth hormone's anabolic effects, promoting cell growth, proliferation, and survival through the IGF-1 receptor and downstream PI3K/Akt signaling pathways. IGF-1 LR3 is used in research to study muscle hypertrophy, hyperplasia (new cell formation), and metabolic regulation.

IGF-1 LR3 is significantly more potent than native IGF-1 and requires careful dosing:

Important: Doses above 100 mcg/day are not recommended due to significantly increased risk of hypoglycemia and other side effects. Most research protocols cap at 50–80 mcg daily. Cycles should be kept short (4–6 weeks maximum) to prevent receptor desensitization and manage risks.

IGF-1 LR3 is administered once daily due to its extended half-life:

• Post-training: The most common timing for muscle-related research, as IGF-1 receptors are upregulated after mechanical stimulus.
• Morning on rest days: Administer before the first meal of the day.

Cycling: IGF-1 LR3 cycles must be kept short: 4–6 weeks maximum, followed by a minimum 4-week break. Extended use leads to IGF-1 receptor desensitization and increases the risk of hypoglycemia and organ growth. Some protocols use 4 weeks on / 4 weeks off exclusively.

Critical: Have fast-acting carbohydrates available during dosing to manage potential hypoglycemic episodes.

• Step 1: Swab vial stoppers with alcohol.
• Step 2: For a 1 mg vial, add 1 mL BAC water to yield 1 mg/mL (100 mcg per 0.1 mL).
• Step 3: Direct the stream along the glass wall. IGF-1 LR3 is delicate — handle gently.
• Step 4: Gently swirl. Do not shake or vortex.
• Step 5: Store at 2–8°C. Use within 28 days. For long-term storage, keep lyophilized powder at -20°C.

Administer subcutaneously or intramuscularly using a 29–31 gauge insulin syringe. Intramuscular injection into the trained muscle is used in some research protocols. Bilateral subcutaneous injection (splitting the dose between two sites) is also employed.

• 20–40 mcg/day: Mild hypoglycemia (manage with carbohydrate intake), possible joint pain, mild water retention.
• 40–60 mcg/day: More pronounced hypoglycemia risk, increased water retention, potential gut distension with prolonged use, numbness/tingling.
• 60–100 mcg/day: Significant hypoglycemia risk (can be dangerous), notable water retention, potential organ growth (intestines, heart) with extended use, jaw/hand growth with chronic elevated IGF-1.

Warning: Hypoglycemia from IGF-1 LR3 can be severe and potentially dangerous. Never inject without access to fast-acting glucose.

IGF-1 LR3 is a potent growth factor for research purposes only. It is not FDA-approved and carries significant risks.

Absolutely contraindicated in subjects with active or suspected malignancies — IGF-1 is a potent mitogen and survival factor for cancer cells. Monitor blood glucose frequently. Do not exceed recommended cycle lengths. The risk of hypoglycemia is serious and potentially life-threatening. Use only under medical supervision with appropriate safety measures in place.