IGF-LR3

IGF-1 LR3 (Long Arg3 IGF-1) is a synthetic analog of Insulin-like Growth Factor-1 (IGF-1).

IGF-1 LR3 acts via the IGF-1 receptor (IGF1R):

Activates:

• PI3K–AKT pathway → protein synthesis, anti-catabolic
• MAPK pathway → cell proliferation

Effects:

• Muscle hypertrophy
• Satellite cell activation
• Increased nutrient uptake (glucose, amino acids)

• Severe primary IGF-1 deficiency
• Growth failure in children
• Lean muscle gain
• Fat loss (indirect via nutrient partitioning)
• Enhanced recovery

SQ (50 mcg) to be taken once daily after meal, 5 days per week.

• Why 5 days per week? (Receptor Sensitivity Rationale)

This is an important practical concept.

 Receptor Dynamics:

• Continuous IGF-1 exposure → IGF-1 receptor downregulation
• Leads to:
• Reduced signaling response
• Diminishing returns over time
• Using 5 days ON / 2 days OFF:
• Allows receptor resensitization
• Helps maintain anabolic responsiveness
• Reduces risk of tachyphylaxis

Common:

• Hypoglycemia (avoided when taken with / after a meal)
• Water retention / edema
• Headaches
• Fatigue

Avoid in:

• Active or history of cancer
• Diabetes or insulin resistance
• Pediatric / growth disorders (unless medically supervised)
• Pregnancy / breastfeeding

Uncontrolled endocrine disorders