Knowing whether you are in ketosis removes the guesswork from keto. Three testing methods are available — each with different accuracy, cost, and convenience profiles.
A small finger-prick blood sample tested with a ketone meter measures beta-hydroxybutyrate (BHB) directly. Target: 0.5–3.0 mmol/L for nutritional ketosis. Cost: ~£1–2 per test strip. Best for: anyone who needs precise, reliable data.
Breath acetone meters (e.g. Ketoscan, Biosense) measure acetone in exhaled breath. Reusable after initial purchase (~£150–250). No ongoing consumable costs. Accuracy is good but slightly less precise than blood testing. Best for: daily testing without ongoing consumable costs.
Ketone urine strips measure acetoacetate, an early ketone, in urine. As fat-adaptation progresses, less acetoacetate appears in urine (it converts to BHB), making strips unreliable for adapted keto dieters. Cheap (~£5 for 100 strips). Best for: beginners in the first 4 weeks only.
Test ketones 2–4 hours after specific meals to learn which foods affect ketosis most. This personalised data is invaluable. Log your findings alongside meals from our keto main dishes and keto snacks.