Fasting glucose

Fasting glucose is one of the earliest warning markers for metabolic health. Elevated levels (hyperglycemia) often appear years before diabetes develops and signal that your body is struggling to regulate sugar efficiently, raising the risk of heart disease, kidney damage, nerve problems, and vision loss. Low fasting glucose (hypoglycemia) is less common but can cause shakiness, sweating, irritability, confusion, and in severe cases fainting or seizures. Nutrition (particularly refined carbohydrates and added sugars), regular physical activity, maintaining a healthy body weight, stress management, and sufficient sleep all strongly influence glucose control.

Detecting abnormal values early allows for preventive lifestyle adjustments and, if needed, medical treatment to protect long-term health.

Most adults benefit from checking fasting glucose once a year. If you're managing pre-diabetes or working on insulin sensitivity, retest every three to six months alongside HbA1c.

At baseline / for screening: Once every 12 months from age 30 as part of a cardiometabolic check. More frequently, every 3 to 6 months, if you have pre-diabetes, type 2 diabetes, polycystic ovary syndrome, or a family history of any of these.

When monitoring an intervention or change: Retest 8 to 12 weeks after a sustained lifestyle change, such as reducing refined carbs and added sugars, increasing physical activity, meaningful weight loss, or improving sleep quality. The same window applies after starting or adjusting glucose-lowering medication (metformin, GLP-1 receptor agonist, SGLT2 inhibitor). If a result was above target, reconfirm sooner once you've begun addressing the most likely driver.

Note: After acute illness, surgery, or starting corticosteroids, fasting glucose can rise transiently. Wait 4 to 6 weeks after recovery or steroid taper before reading the next value as your stable baseline.