Insulin
Hormone that regulates blood sugar
17 of 22 providers
Metabolic Health / Glucose
Fasting:2.6-24.9 μIU/mL, Optimal:<10 μIU/mL
What is Insulin?
Insulin is a peptide hormone produced by beta cells in the pancreas in response to rising blood glucose (after meals). Insulin's primary job is to shuttle glucose from the bloodstream into cells (muscle, fat, liver) for energy or storage. It also promotes fat storage, suppresses lipolysis (fat breakdown), and inhibits gluconeogenesis (liver glucose production). Measuring fasting insulin provides critical insight into insulin resistance—the condition where cells become less responsive to insulin, forcing the pancreas to produce more insulin to maintain normal blood glucose.
Here's the critical insight:insulin rises YEARS before glucose. In the progression toward type 2 diabetes, the pancreas compensates for insulin resistance by secreting more and more insulin to keep glucose normal. You can have perfectly normal fasting glucose (70-90 mg/dL) and HbA1c (<5.7%) while having dangerously high insulin (>10 mcIU/mL), indicating severe insulin resistance and metabolic dysfunction. By the time fasting glucose rises above 100 mg/dL, you've already had insulin resistance for 5-10 years, and your beta cells are starting to fail. Measuring fasting insulin catches metabolic disease a decade earlier than glucose or HbA1c.
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is the gold standard calculated marker:(Fasting Glucose × Fasting Insulin) / 405. HOMA-IR >2.0 indicates insulin resistance;>2.5 is concerning;>5.0 is severe. HOMA-IR is more sensitive than glucose or HbA1c for detecting early metabolic dysfunction and predicts future diabetes, cardiovascular disease, and all-cause mortality.
Why Insulin (and Insulin Resistance) Matters for Longevity
- Metabolic health:Insulin resistance is THE root cause of metabolic syndrome—obesity (especially visceral fat), hypertension, dyslipidemia (high triglycerides, low HDL), fatty liver, type 2 diabetes.
- Cardiovascular disease:Insulin resistance drives atherosclerosis, hypertension, and inflammation. High insulin (hyperinsulinemia) independently predicts heart attacks, stroke, and CVD mortality, even with normal glucose.
- Alzheimer's disease (Type 3 Diabetes):Insulin resistance in the brain impairs glucose metabolism and promotes amyloid plaque accumulation. Alzheimer's is now called "Type 3 Diabetes."High insulin associated with 2-3x higher dementia risk.
- Cancer:Insulin is a growth factor. Chronic hyperinsulinemia promotes cell proliferation and cancer growth (breast, colon, prostate). Insulin resistance associated with 30-50% higher cancer risk.
- Aging and longevity:Lower insulin and insulin sensitivity are hallmarks of longevity. Centenarians have exceptional insulin sensitivity. Calorie restriction and fasting extend lifespan partly by lowering insulin.
- PCOS:Insulin resistance drives androgen excess in women, causing PCOS (irregular periods, hirsutism, infertility). Lowering insulin reverses PCOS.
Optimal vs Standard Ranges
Optimal (Longevity)<5 mcIU/mL (fasting)▼
- Exceptional insulin sensitivity
- Associated with longevity, low CVD risk, optimal metabolic health
- Target for healthspan optimization
Good (Standard)5-7 mcIU/mL▼
- Normal insulin sensitivity
- Acceptable for most people but room for improvement with lifestyle optimization
Suboptimal (Early Insulin Resistance)7-10 mcIU/mL▼
- Mild insulin resistance
- Beta cells compensating to maintain normal glucose
- Intervene NOW with diet, exercise, weight loss to reverse
Insulin Resistance10-15 mcIU/mL▼
- Moderate insulin resistance
- HOMA-IR likely >2.5
- High risk of progressing to prediabetes/diabetes
- Requires aggressive lifestyle intervention
Scientific Evidence
High fasting insulin >10 mcIU/mL indicates insulin resistance even if glucose is normal. HOMA-IR >2.0 confirms insulin resistance.
Low insulin is rare and usually indicates:|Type 1 diabetes:Autoimmune destruction of pancreatic beta cells. No insulin production. Requires exogenous insulin replacement.|Advanced type 2 diabetes with beta cell failure:After years of hyperinsulinemia, beta cells burn out and insulin production drops. Glucose rises dramatically.|Hypopituitarism:Pituitary failure reduces growth hormone and other hormones that stimulate insulin secretion.
Obesity:Visceral fat secretes inflammatory cytokines (TNF-alpha, IL-6) and free fatty acids that block insulin signaling.|Sedentary lifestyle:Physical inactivity reduces GLUT4 expression in muscle, worsening insulin resistance.|High-carb, processed diet:Chronic carb/sugar intake causes chronic hyperinsulinemia → downregulation of insulin receptors → resistance.|Metabolic syndrome:Cluster of visceral obesity, hypertension, dyslipidemia, insulin resistance. Affects 35% of US adults.|Genetics:Family history of type 2 diabetes increases risk 2-6x. Certain ethnicities (South Asian, Hispanic, African American) have higher risk.|PCOS:Insulin resistance drives ovarian androgen production in 70-80% of PCOS cases.|Chronic stress and cortisol excess:Cortisol promotes gluconeogenesis and antagonizes insulin.|Sleep deprivation:Even short-term sleep restriction (≤6 hours) worsens insulin resistance by 30-40%.|Medications:Glucocorticoids (prednisone), atypical antipsychotics (olanzapine), protease inhibitors (HIV meds).|Aging:Insulin sensitivity declines with age due to sarcopenia, fat gain, and mitochondrial dysfunction.
Type 1 diabetes:Autoimmune destruction of pancreatic beta cells → no insulin production → high glucose, low/absent insulin.|Advanced type 2 diabetes with beta cell exhaustion:After years of compensatory hyperinsulinemia, beta cells fail → insulin production drops → glucose rises.|Insulinoma (very rare):Insulin-secreting pancreatic tumor causes episodic hypoglycemia with inappropriately high insulin. Diagnosed with supervised fasting test.|Exogenous insulin use:Type 1 diabetics or advanced type 2 diabetics on insulin therapy will have high measured insulin.
Insulin Resistance Predicts Diabetes Decades Before Diagnosis
Fasting insulin rises 5-10 years before glucose becomes abnormal. Studies show elevated insulin (>10 mcIU/mL) predicts type 2 diabetes development with 3-4x higher risk over next decade, even with normal glucose. HOMA-IR >2.5 predicts diabetes with 5-6x higher risk. Measuring insulin catches pre-diabetes much earlier than glucose or HbA1c.
Hyperinsulinemia and Cardiovascular Disease
Elevated fasting insulin independently predicts cardiovascular events (heart attack, stroke) and CVD mortality, even after adjusting for glucose, BMI, and other risk factors. Meta-analyses show each 5 mcIU/mL increase in fasting insulin associated with 20-30% higher CVD risk. Insulin promotes atherosclerosis, hypertension, and vascular smooth muscle proliferation.
Insulin Resistance and Alzheimer's Disease
Insulin resistance in the brain impairs glucose metabolism and promotes amyloid-beta accumulation. Alzheimer's is increasingly called "Type 3 Diabetes."High insulin and HOMA-IR associated with 2-3x higher dementia risk. Metformin and lifestyle interventions that improve insulin sensitivity may reduce Alzheimer's risk.
Which Providers Test Insulin?
Full Provider Comparison
| Provider | Includes | Annual Cost | Biomarkers |
|---|---|---|---|
 Superpower | ✓ | $199 | 100+ (150 with ratios) |
 WHOOP Advanced Labs | ✓ | $349 | 65 |
 Labcorp OnDemand | ✓ | $398 | 30+ |
| ✓ | $486 | 40+ | |
| — | $444 | 288 | |
| ✓ | $349 | 100+ | |
| ✓ | $761 | 54 | |
 Function Health | ✓ | $365 | 160+ |
| ✓ | $250 | 65 | |
| ✓ | $495 | 70+ | |
| ✓ | $895 | 100+ | |
| ✓ | $1950 | 150+ | |
| ✓ | $375 | 80+ | |
| — | $Varies | 75+ | |
| ✓ | $190 | 100+ | |
| ✓ | $99 | 50 | |
| — | $124 | 60 | |
| — | $199 | 50 | |
| ✓ | $499 | 120+ | |
| ✓ | $4188 | 70-80+ | |
| — | $375 | 85 | |
| ✓ | $700 | 128 |
Frequently Asked Questions
What is Insulin?
Hormone that regulates blood sugar
What is the optimal range for Insulin?
The standard reference range for Insulin is Fasting:2.6-24.9 μIU/mL, Optimal:<10 μIU/mL. Optimal ranges may differ based on individual health goals and expert recommendations.
Which blood test providers include Insulin?
17 out of 22 blood testing providers include Insulin in their panels. This biomarker is widely available across major providers.
What category does Insulin fall under?
Insulin is categorized under Metabolic Health / Glucose. This category includes biomarkers that help assess related aspects of health and wellness.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed:2026-02-20