IGF-1 — Growth + Aging Trade-Off
IGF-1 mediates growth hormone action — too low tracks with frailty; too high associates with cancer risk in cohort data. The optimal range is narrow and age-dependent.
IGF-1 (insulin-like growth factor 1) mediates the tissue-building effects of growth hormone — high values support muscle mass and recovery; very high values associate with elevated cancer risk in long-term cohorts; very low values track with frailty, making the optimal range narrower than most longevity-focused biomarkers.
The biomarker
- Name: Insulin-Like Growth Factor 1 (IGF-1)
- Units: ng/mL
- Standard reference range: 50–300 ng/mL (varies significantly by age and lab)
- Optimal range (adult, age-adjusted): 100–200 ng/mL
How to read your result
| Value | Interpretation |
|---|---|
| < 100 ng/mL (low for age) | Frailty risk — investigate nutrition adequacy, sleep quality, and anabolic hormone status (testosterone, DHEA-S) |
| 100–200 ng/mL | Acceptable trade-off — supports muscle and recovery without the cancer-risk signal seen at higher values |
| > 200 ng/mL (high for age) | Discuss with clinician — consider cancer-surveillance context; high IGF-1 in older adults warrants investigation |
IGF-1 falls with age. Always compare against an age-matched reference range, not a flat number. Ranges above are adult approximations; ask your lab for the age-stratified reference.
What moves the needle
- Protein intake. Adequate protein (1.2–1.6 g/kg body weight for healthy adults) is the primary dietary driver of IGF-1. Chronic restriction — as in aggressive calorie-cutting or very low-protein diets — suppresses IGF-1 and contributes to muscle loss with age.
- Sleep. Growth hormone is released in deep-sleep pulses; IGF-1 is the downstream mediator. Seven to nine hours of quality sleep supports the natural GH/IGF-1 rhythm. Chronic sleep debt measurably suppresses both.
- Resistance training. Strength work acutely elevates GH and IGF-1; sustained training maintains the anabolic environment that keeps IGF-1 in the healthy range in older adults.
- Body fat. Visceral fat reduces GH pulsatility and suppresses IGF-1 — one of several metabolic channels through which excess body fat accelerates functional ageing.
Why ask for it
- IGF-1 is not included in standard metabolic panels. You have to request it specifically — often through an endocrinologist or a functional-medicine provider.
- In the longevity context, it sits at a genuine biological trade-off: the same pathway that supports muscle growth and repair (via mTOR/IGF-1 signalling) also promotes cell proliferation. Understanding where you sit helps you calibrate the lifestyle levers (protein, sleep, training) rationally.
- Low IGF-1 is underdiagnosed as a contributor to unexplained fatigue, muscle wasting, and slow recovery in adults over 40.
- A single test is sufficient to establish context; retest every 12–24 months or after a sustained lifestyle change.
Related protocols
- Zinc — Immune + Hormone Cofactor
- TSH, Free T3 and T4 — Thyroid Panel
- Testosterone, Total and Free (Men)
Sources
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
