Metabolic
    Moderate Evidence

    Insulin-Like Growth Factor

    Balanced IGF-1 levels for tissue growth and repair.

    TL;DR

    IGF-1 is a balance, not a maximise-or-minimise target: too low impairs muscle and bone, too high is associated with cancer risk. Protein intake and training set the level in most people.

    Why It Matters

    IGF-1 mediates most growth hormone effects on muscle, bone and tissue repair. Low levels in older adults track frailty and poor recovery, while high-normal levels have been associated in cohort studies with increased prostate and breast cancer risk.

    How to Measure

    Biomarkers

    Serum IGF-1 (age-adjusted)
    IGFBP-3
    Protein intake
    Fasting insulin
    Lean body mass

    Optimization Protocol

    Consume adequate protein at 1.2-1.6 g/kg for most adults and train with resistance to support the anabolic response. Avoid deliberately pushing IGF-1 above the age-appropriate range. If levels are low, check for undernutrition, hypothyroidism or liver disease before considering endocrine causes.

    Supporting Supplements

    Supporting Research

    Frequently Asked Questions

    Typical Timeframe

    8-12 weeks

    Research Summary

    Studies9
    Supplements3
    Evidence
    Moderate Evidence

    My Notes

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    This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.