Fasting Insulin
Fasting insulin reveals insulin resistance years before fasting glucose or A1C move. It is one of the most underused, highest-signal metabolic biomarkers.
What Fasting Insulin measures
Fasting insulin measures circulating insulin after an overnight fast. It quantifies the basal pancreatic effort required to maintain euglycemia and is the earliest reliable signal of insulin resistance — typically rising years before fasting glucose or A1C drift.
Clinical significance
Insulin resistance is the upstream driver of metabolic syndrome, NAFLD, PCOS, ED, low testosterone in men, and cardiovascular disease. Standard metabolic screening that relies only on glucose and A1C misses the resistance phase. Provider-reviewed wellness adds fasting insulin so optimization can begin years earlier.
How oMeds reviews it
Fasting insulin is the headline metabolic marker in optimization. Values above 7 µIU/mL with normal glucose still flag insulin resistance and merit lifestyle + nutrition intervention. Values above 10 µIU/mL trigger HOMA-IR calculation and lipid + ApoB review.
Standard clinical reference intervals
Lab-reported reference ranges from established standards bodies. These are diagnostic thresholds — they do not represent optimization targets.
Source: Quest Diagnostics fasting reference interval
Lab ranges are broad; clinical thresholds are tighter.
oMeds optimization targets
Editorial bands that inform provider-reviewed conversations. These are wellness targets, not diagnostic thresholds.
A fasting insulin under 7 µIU/mL most consistently reflects intact insulin sensitivity and lowest cardiometabolic risk in provider-reviewed wellness.
oMeds optimization ranges are editorial targets that inform conversations with a licensed provider. They are NOT diagnostic thresholds and do not replace lab reference ranges.
Fasting Insulin — frequently asked
Why measure insulin if glucose is normal?
Insulin rises years before glucose does. Catching the resistance phase enables lifestyle and pathway interventions while the metabolic system is still flexible.
What is HOMA-IR?
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) = fasting insulin × fasting glucose ÷ 405. It standardizes insulin resistance assessment; oMeds reviews HOMA-IR whenever fasting insulin is elevated.
Source literature
- ADA Standards of Care 2024 · Diabetes Care
- Insulin resistance and cardiometabolic risk (Reaven) · PubMed
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