IGF-1
IGF-1 is your body’s growth signal — a stable proxy for growth hormone. The fascinating longevity paradox: more muscle-building power, but potentially faster cellular aging.
IGF-1 is made by your liver in response to growth hormone. It drives muscle growth, bone density, and metabolism. But here’s the twist: in every animal model studied, reducing IGF-1 signalling extends lifespan. The sweet spot for humans appears to be mid-range — enough for function, not so much that it accelerates aging.
What is the IGF-1 test?
Growth hormone (GH) itself is nearly impossible to test — it pulses throughout the day with huge swings. IGF-1, made by your liver in response to GH, stays stable in your blood for 15–20 hours. That makes it the practical way to assess your GH axis.
IGF-1 tells you whether your body’s growth and repair signalling is adequate, excessive, or declining — important for anyone over 35 who cares about maintaining muscle mass, bone density, and metabolic health as they age.
What your number means
| Age | Lab range (ng/mL) | Longevity target |
|---|---|---|
| 20–30 | 182–780 | 180–260 ng/mL (mid-range) |
| 30–45 | 115–307 | 150–220 ng/mL |
| 45–60 | 94–252 | 130–200 ng/mL |
| 60+ | 67–205 | Upper half of age range |
Very high IGF-1 is linked to increased cancer risk. Very low IGF-1 leads to frailty and muscle loss. Mid-range is the longevity sweet spot.
How to improve it
Protein intake above 1.2g/kg/day is the strongest dietary driver. Resistance training stimulates GH and raises IGF-1. Quality sleep — especially deep sleep — is when most GH is produced.
If IGF-1 is too high: fasting, caloric restriction, and plant-based diets all lower it. Don’t try to maximise IGF-1 — the J-shaped curve means both extremes are unfavourable.
Want to track your IGF-1?
eterni tracks your IGF-1 alongside body composition, protein intake, and training — so you can find your personal optimal.
Get early accessFrequently Asked Questions
What is a good IGF-1 level for longevity?
Mid-range for your age — roughly 150–220 ng/mL for ages 30–45. The relationship is J-shaped: very high IGF-1 is linked to cancer risk, very low to frailty. Avoid both extremes.
Does higher IGF-1 mean better health?
Not straightforwardly. Higher IGF-1 builds muscle and supports metabolism. But in every animal model, reducing IGF-1 signalling extends lifespan. In humans, the current consensus favours mid-range optimisation, not maximum.
How do I raise IGF-1 naturally?
Protein intake above 1.2g/kg/day, resistance training, quality sleep (especially deep sleep), and adequate zinc and magnesium. These are the natural levers without peptides or pharmaceuticals.
Does fasting lower IGF-1?
Yes — even short-term fasting (24–72 hours) significantly reduces IGF-1. This is one mechanism behind fasting's proposed longevity benefits. If you're testing IGF-1, eat normally for a few days beforehand to get an accurate baseline.
The longevity paradox explained
In Ames dwarf mice (GH receptor knockout), lifespan extends 55%. In worms with reduced IGF-1 signalling, lifespan doubles. Every major model organism shows the same pattern: lower insulin/IGF-1 signalling pathway activity = longer life. In humans, population data shows a J-shaped curve — both extremes are bad, mid-range appears optimal.
How it’s measured
A simple blood draw, no fasting required. Available at all major Indian labs for ₹800–1,500. Results may be artificially low during caloric restriction or fasting protocols — test while eating normally.
Cancer considerations
IGF-1 promotes cell growth and inhibits programmed cell death. Observational studies show associations between elevated IGF-1 and breast, prostate, and colorectal cancer. This is why aggressively boosting IGF-1 with peptides without clear medical need carries risk.
Connected supplements
Creatine supports muscle mass alongside healthy IGF-1 levels. Zinc and magnesium support GH axis function. Whey protein is the most efficient dietary IGF-1 driver.
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eterni connects your lab results, supplements, and retests — so you can see the trajectory, not just a snapshot.
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