HOMA-IR vs fasting insulin — which should I track?
HOMA-IR is the standardized derivation; fasting insulin is one of its inputs. HOMA-IR integrates fasting insulin and fasting glucose into a single insulin-sensitivity index, which makes it the more interpretable single number for tracking.
Full answer
Fasting insulin is one input; HOMA-IR is the integrated index. HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is calculated as fasting insulin × fasting glucose ÷ 405, which combines the two earliest movers in metabolic dysfunction into a single standardized number. Tracking fasting insulin alone misses the glucose context (the same insulin level can mean very different things depending on the glucose it is holding down), and tracking fasting glucose alone misses the early compensatory rise in insulin. HOMA-IR integrates both. It is not a diagnostic gold standard (the euglycemic clamp is), but for ongoing wellness monitoring it is the most useful single metric. Provider review reads HOMA-IR alongside A1c, lipids, ApoB, hs-CRP, and body composition for the full picture.
Educational. Not a substitute for individualized provider review.
- HOMA-IR — Primary source · oMeds
- Reviewed by Dr. Laura Purdy, MD, MBA · Clinical Director, oMeds · Last reviewed 2026-05-29