Fasting Glucose
Blood sugar level after fasting
20 of 22 providers
Metabolic Health / Glucose
Normal:70-99 mg/dL, Prediabetes:100-125 mg/dL, Diabetes:≥126 mg/dL
What is Fasting Glucose?
Fasting glucose measures the amount of sugar (glucose) in your blood after not eating for at least 8 hours. Glucose is your body's primary energy source, derived from carbohydrates you eat. Your pancreas releases insulin to help cells absorb glucose, and fasting glucose shows how well this system works at baseline.
When you fast, your liver releases stored glucose (glycogen) to maintain blood sugar. In healthy individuals, insulin keeps this process balanced. Elevated fasting glucose indicates your body is either not producing enough insulin (Type 1 diabetes), not responding well to insulin (insulin resistance/Type 2), or your liver is releasing too much glucose.
Fasting glucose is the most basic diabetes screening test but has limitations. It only shows a snapshot in time and can be affected by stress, illness, or recent intense exercise. HbA1c and fasting insulin provide complementary information about long-term glucose control and insulin sensitivity.
Beyond Diabetes:Metabolic Health Window
- Pre-diabetes detection:Levels 100-125 mg/dL indicate impaired fasting glucose and increased diabetes risk
- Cardiovascular connection:Even "high-normal"glucose (>90 mg/dL) associated with increased heart disease risk
- Cancer risk:Chronically elevated glucose feeds cancer cell growth through the Warburg effect
- Cognitive impact:High glucose damages brain blood vessels and accelerates cognitive decline
- Longevity marker:Centenarians typically maintain low fasting glucose throughout life
Optimal vs Standard Ranges
Optimal (Longevity)70-85 mg/dL▼
- Associated with lowest all-cause mortality and best metabolic health
- Many longevity-focused practitioners target this range
- Indicates excellent insulin sensitivity and metabolic flexibility
Normal (Standard)85-99 mg/dL▼
- Within standard reference range but may indicate early insulin resistance
- Consider lifestyle optimization and checking fasting insulin to assess HOMA-IR
Pre-diabetes100-125 mg/dL▼
- Impaired fasting glucose
- 5-10% annual conversion to diabetes without intervention
- Aggressive lifestyle modification can reverse
- Consider metformin if lifestyle changes insufficient
Diabetes>126 mg/dL▼
- Diagnostic for diabetes if confirmed on repeat testing
- Requires medical management
- Check HbA1c for confirmation and long-term control assessment
Scientific Evidence
Glucose and All-Cause Mortality
Meta-analysis of 97 prospective studies found that fasting glucose levels above 100 mg/dL were associated with progressively increased mortality, with optimal levels below 90 mg/dL.
Pre-diabetes Progression
Study of 3,234 pre-diabetic adults showed intensive lifestyle intervention reduced progression to diabetes by 58% compared to placebo, more effective than metformin (31%).
Dawn Phenomenon
Research shows fasting glucose is naturally highest in early morning due to cortisol and growth hormone release. True baseline should be measured after 8-12 hour fast.
Source:
Which Providers Test Fasting Glucose?
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 Fasting Glucose?
Blood sugar level after fasting
What is the optimal range for Fasting Glucose?
The standard reference range for Fasting Glucose is Normal:70-99 mg/dL, Prediabetes:100-125 mg/dL, Diabetes:≥126 mg/dL. Optimal ranges may differ based on individual health goals and expert recommendations.
Which blood test providers include Fasting Glucose?
20 out of 22 blood testing providers include Fasting Glucose in their panels. This biomarker is widely available across major providers.
What category does Fasting Glucose fall under?
Fasting Glucose 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