# Glucose

Source: https://synapse-lifestyle.com/en/reference-guide/biomarkers/glucose

Unit: mg/dL

## What is Glucose?

Fasting glucose is your blood sugar after a night without food. It shows how well your body keeps your sugar level at rest. A stable fasting value points to a smoothly running metabolism.

## Clinical frame

**Fasting glucose reflects glucose regulation after at least 8 hours without calorie intake** and is an important parameter for detecting prediabetes and diabetes [2].

In the context of insulin resistance, however, fasting glucose is above all a **later marker of metabolic dysregulation**. Insulin resistance and compensatory hyperinsulinaemia can be present for years while fasting glucose remains normal [1]. A normal value therefore does not rule out insulin resistance.

When fasting glucose starts to rise, this mainly points to **hepatic insulin resistance and increasing beta-cell dysfunction**. Insulin then no longer manages to suppress glucose production by the liver sufficiently, so glucose remains elevated even in the fasting state [3].

For the early detection of insulin resistance, **HOMA-IR, the TyG index and triglycerides/HDL** are more sensitive than fasting glucose alone [1]. The value therefore gains its meaning mainly in combination with other metabolic markers and the broader risk profile.

## What moves this value?

Too little or too much sleep, stress and little exercise can temporarily raise your morning value. A high calorie intake, fast carbohydrates, sugary drinks and heavily processed food also play a part.

**Healthy weight loss often has the greatest impact.** Regular exercise, walking after meals, fibre-rich food and a regular sleep pattern help improve your value further.

## What this connects

- [HbA1c](https://synapse-lifestyle.com/en/reference-guide/biomarkers/hba1c)
- [HOMA-IR](https://synapse-lifestyle.com/en/reference-guide/biomarkers/homa-ir)
- [Triglycerides](https://synapse-lifestyle.com/en/reference-guide/biomarkers/triglycerides)

Developed and reviewed with the Synapse [medical advisory board](https://synapse-lifestyle.com/en/advisory-board).

## References

1. Roden, M. & Shulman, G. I. The integrative biology of type 2 diabetes. Nature 576, 51–60 (2019). https://doi.org/10.1038/s41586-019-1797-8
2. Unnikrishnan, R. et al. Prediabetes. Nat Rev Dis Primers 11, 49 (2025). https://doi.org/10.1038/s41572-025-00635-0
3. Bock, G. et al. Contribution of hepatic and extrahepatic insulin resistance to the pathogenesis of impaired fasting glucose: role of increased rates of gluconeogenesis. Diabetes 56, 1703–1711 (2007). https://doi.org/10.2337/db06-1776

- [Read more in the reference guide](https://synapse-lifestyle.com/en/reference-guide/metabolism#Consequence-CSInsulin-FGluc)
- [All biomarkers in the guide](https://synapse-lifestyle.com/en/reference-guide#biomarkers)

The colour zones are personal: they depend on age, sex, risk and history, and appear in the patient's own report.

Insights to discuss with the patient, not a diagnostic instrument.