# IGF-1

Insulin-like growth factor 1 (IGF-1) is made mainly in your liver, under stimulation from growth hormone (GH). It carries out many of GH's anabolic effects on muscle, bone, and other tissues. As a biomarker, IGF-1 is a stable stand-in for GH activity, and it reflects your nutritional status and protein intake. Higher levels in adulthood are linked to greater cancer risk. Very low levels are observationally tied to frailty and reduced lean mass. But that link may partly reflect underlying disease or malnutrition, rather than a direct causal harm. So the net relationship between IGF-1 and human longevity is complex, and not simply U-shaped.

## Sources

- Key TJ, Appleby PN, Reeves GK, Roddam AW. (2010). Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: pooled individual data analysis of 17 prospective studies. Lancet Oncology. https://doi.org/10.1016/S1470-2045(10)70095-4
- Burgers AMG, Biermasz NR, Schoones JW, Pereira AM, Renehan AG, Zwahlen M, et al.. (2011). Meta-analysis and dose-response metaregression: circulating insulin-like growth factor I (IGF-I) and mortality. Journal of Clinical Endocrinology & Metabolism. https://doi.org/10.1210/jc.2011-1377
- Milman S, Atzmon G, Huffman DM, Wan J, Crandall JP, Cohen P, et al.. (2014). Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity. Aging Cell. https://doi.org/10.1111/acel.12213

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_Canonical: https://longevity-switzerland.com/en/glossary/igf-1-biomarker · Part of Longevity Cities · Updated 2026-06-22_