β-cell function (HOMA-β)

HOMA-β (Homeostatic Model Assessment of Beta-cell function) is a quick estimate of how well your pancreas makes insulin. It uses just fasting blood values. The formula is (20 × fasting insulin in µU/mL) divided by (fasting glucose in mmol/L − 3.5). It mostly captures your baseline insulin output. It lines up reasonably with more demanding tests, like the disposition index from an IV glucose tolerance test. But it cannot measure the dynamic insulin surge after glucose. Your β-cell mass and function decline slowly with age. That decline speeds up with insulin resistance, fat-and-sugar toxicity (glucolipotoxicity), and chronic low-grade inflammation. Tracking HOMA-β next to HOMA-IR gives a paired picture of insulin supply and demand. That is useful for spotting prediabetes risk and for longevity-focused metabolic checks.

Last reviewed: June 22, 2026

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