Beta-hydroxybutyrate (BHB)

Beta-hydroxybutyrate (BHB) is a major ketone body circulating in blood during ketosis. The liver forms it by reducing acetoacetate, and tissues can convert it back to acetoacetate before using it for energy. Chemically, BHB is a hydroxy acid, but it is grouped with acetoacetate and acetone as a ketone body.¹

Medical disclaimer. This article is for general educational purposes only and is not medical advice. It is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider before starting the ketogenic diet or making changes to your diet, exercise, or medication — especially if you are pregnant or breastfeeding, take medication, or have a medical condition such as diabetes, or kidney, liver, or heart disease. See our editorial & medical-review policy.

Why blood tests measure BHB

BHB becomes the predominant circulating ketoacid during DKA, while common urine strips measure acetoacetate. The 2024 international consensus recommends direct venous or capillary BHB measurement for DKA assessment and monitoring when it is available. Urine acetoacetate can lag early in DKA and remain elevated during recovery.²

A blood ketone meter estimates BHB from a finger-prick sample. The result shows the concentration at that moment. It does not identify the cause, measure metabolic acidosis, or show how much stored body fat is being used.

What does a BHB result mean?

Context determines meaning. BHB can rise with carbohydrate restriction, fasting, prolonged exercise, illness, pregnancy, alcohol use, insulin deficiency, SGLT2-inhibitor treatment, or an exogenous ketone product. A higher result is not automatically a health benefit.

For DKA, BHB at least 3.0 mmol/L satisfies the ketone component of the current consensus criteria. It does not diagnose DKA alone. DKA also requires diabetes or glucose at least 200 mg/dL and venous pH below 7.3 and/or bicarbonate below 18 mmol/L.² Home meters do not measure pH or bicarbonate.

Euglycemic DKA can occur below 200 mg/dL glucose, particularly with SGLT2 inhibitors, pregnancy, reduced food intake, alcohol-related impaired gluconeogenesis, liver failure, or insulin already taken before testing. A reassuring glucose reading therefore cannot cancel concerning symptoms or ketones.²

Seek emergency care now for persistent vomiting, severe abdominal pain, deep or difficult breathing, confusion, fainting, or marked drowsiness. These signs are especially concerning for DKA with known or possible diabetes, pregnancy, or SGLT2-inhibitor use; do not wait for very high glucose.

BHB from supplements is not the same as endogenous ketosis

Exogenous ketones can raise measured BHB without carbohydrate restriction and without showing that stored body fat is being lost. This is another reason not to interpret one BHB result as a diet-quality, weight-loss, or safety score.

Most people following a ketogenic diet for general purposes do not need routine BHB testing. People at risk of DKA should use the personalized thresholds and actions in their diabetes sick-day plan.

Frequently Asked Questions

Is BHB a ketone?

BHB is classified as one of the three ketone bodies even though its chemical structure is a hydroxy acid rather than a true ketone.

Does a BHB result prove nutritional ketosis?

It shows circulating BHB at that moment. Diet, fasting, exercise, illness, medication, pregnancy, alcohol, and exogenous ketones can all affect the result, so the number does not identify one cause.

Does BHB at 3.0 mmol/L prove DKA?

No. It satisfies the ketone component of the consensus criteria, but DKA also requires metabolic acidosis and diabetes or qualifying hyperglycemia.

Should I try to raise BHB?

There is no universally beneficial BHB target for general dieting. Routine testing or chasing a higher number is unnecessary outside an individualized diabetes plan or clinician-directed therapeutic protocol.

See also: Ketosis · Ketoacidosis (DKA) · Blood ketone meter · Urine ketone strips · Detailed ketosis vs DKA guide · Full glossary

Works cited

1. Multi-Dimensional Roles of Ketone Bodies in Fuel Metabolism, Signaling, and Therapeutics — Puchalska P, Crawford PA, Cell Metabolism. 2017;25(2):262–284, doi:10.1016/j.cmet.2016.12.022 https://pmc.ncbi.nlm.nih.gov/articles/PMC5313038/
2. Hyperglycemic Crises in Adults With Diabetes: A Consensus Report — Umpierrez GE, Davis GM, ElSayed NA, et al., Diabetes Care. 2024;47(8):1257–1275, doi:10.2337/dci24-0032 — August 23, 2026 https://pmc.ncbi.nlm.nih.gov/articles/PMC11272983/

Article history

1. August 23, 2026Updated
2. August 18, 2026First published