Why we measure it

Insulin resistance is the underlying metabolic disturbance that precedes type 2 diabetes by a decade or more. During this long period, fasting glucose and HbA1c may remain completely normal while fasting insulin is quietly rising — the pancreas compensating by working harder. Standard clinical screening misses this window entirely because it only measures glucose. Fasting insulin and HOMA-IR make the compensatory state visible before glucose moves. Beyond diabetes risk, insulin resistance is implicated across a wide range of conditions: cardiovascular disease, non-alcoholic fatty liver disease, polycystic ovary syndrome, hypertension, certain cancers, and cognitive decline. A landmark paper by Desprès et al. in the New England Journal of Medicine (1996) demonstrated that hyperinsulinaemia independently predicts ischemic heart disease — separate from any effect on lipids or blood pressure. Reaven's 1988 Banting Lecture formally established insulin resistance as a central pathophysiological mechanism across these conditions, coining the concept now known as metabolic syndrome. Data from the San Antonio Heart Study and the Insulin Resistance Atherosclerosis Study showed that elevated fasting insulin predicts the development of type 2 diabetes even when fasting glucose is normal.

Why every 3 months

Insulin sensitivity responds to lifestyle on a timescale of weeks to months — diet composition, physical activity, sleep quality, and body composition all shift HOMA-IR measurably within a single quarter. This makes HOMA-IR one of the most responsive markers to track in the Pulse protocol. A dietary change, an exercise intervention, or improved sleep that genuinely improves insulin sensitivity will be visible in the next quarterly draw. Annual testing cannot resolve this; nine months of drift or improvement goes undetected. Quarterly tracking of fasting insulin and HOMA-IR is how you see whether lifestyle is actually changing the underlying metabolic state — not just how it feels, but what it is.

What movement means

For HOMA-IR, there is no single authoritative clinical guideline that defines diagnostic thresholds the way the ADA defines HbA1c bands. The ranges below are drawn from research literature across multiple epidemiological cohorts and are reported here as reference values from those studies — not as clinical diagnostic criteria set by Nexuses. Thresholds also vary by population, ethnicity, body composition, and laboratory method, which is why they should be read as directional signals rather than absolute cutoffs. For fasting insulin, reference ranges are even less standardised across laboratories and guidelines. Values above approximately 15–25 µIU/mL in the fasted state are frequently associated with insulin resistance in the research literature when glucose is normal, but no single threshold has been adopted by a major clinical body.

In the protocol