3 Ketone Bodies Explained: BHB vs Acetoacetate vs Acetone

When people talk about ketones, they usually mean one molecule. Your body actually makes three ketone bodies: acetoacetate, beta-hydroxybutyrate (BHB) and acetone. All three come out of the same pathway in the liver, but they behave very differently in your blood, your breath and your urine. That is why a urine strip, a breath meter and a finger-stick meter can give you three different answers on the same morning.

I’ve spent years building goBHB®, so you know which one I care about most. But you can’t make sense of a BHB supplement without knowing how it fits with the other two, so below I cover what each one is and what human studies show happens to all three when you drink BHB.

What Are Ketone Bodies?

When carbohydrate runs low (during a fast, on a ketogenic diet or late in a long workout), fat tissue releases fatty acids and the liver breaks them down. The surplus gets turned into acetoacetate. From there, acetoacetate either gets converted to D-BHB by the enzyme D-beta-hydroxybutyrate dehydrogenase (BDH), or it breaks down, on its own or with enzyme help, into acetone and carbon dioxide.

The liver makes ketones but can’t burn them. It lacks the enzyme needed to feed them back into its own energy cycle, so ketone bodies are made for export to the brain, heart, skeletal muscle and kidneys. Chemistry footnote: BHB isn’t technically a ketone (it carries a hydroxyl group), but it is made from acetoacetate and turns back into it.

Acetoacetate (AcAc)BHBAcetoneWhere it comes fromMade first, in the liver, from fatty acidsMade from acetoacetate by an enzyme (BDH)Forms when acetoacetate breaks downWhat it doesFuel for the brain, heart and muscleThe main ketone fuel in bloodMostly a byproductHow it leaves or gets testedUrine stripsFinger-stick blood meters (D-BHB only)Breath meters; largely exhaledIn supplements?RarelyYes: salts, free acid and estersNo

Source: StatPearls, Biochemistry, Ketogenesis (updated Dec 2025); Stubbs et al., 2017.

BHB vs Acetoacetate: Two Forms of the Same Fuel

Acetoacetate and D-BHB shift back and forth all day, and in blood BHB usually carries most of the load. In the Oxford study by Stubbs and colleagues, the ratio of D-BHB to acetoacetate after a ketone ester drink was about 6 to 1 when people were fasted and 4 to 1 after a meal. Tissues that burn BHB convert it back to acetoacetate first, which is why drinking BHB also raises acetoacetate.

A 2025 pilot study measured that directly. Holland-Winkler and colleagues gave 13 healthy adults 7 g of racemic sodium BHB (half D, half L) or a placebo after a 10-hour fast, in a triple-blind crossover. Thirty minutes later, plasma acetoacetate measured by mass spectrometry had risen by 0.57 mM on average with BHB versus 0.07 mM with placebo (p = 0.009), and the rise tracked the rise in BHB. Urine dipsticks went from zero to positive for acetoacetate in the BHB condition. It had no outside funding or conflicts, but it was small and reported a single 30-minute reading. If you want to know how the salt, free acid and ester forms compare, I covered that in BHB free acid vs BHB salts.

Acetone: The Ketone You Breathe Out

Acetone forms when acetoacetate breaks apart. It is a minor byproduct, and most of it leaves through your lungs, which is why breath meters can detect it.

Breath acetone lags behind blood BHB. In the Stubbs study it climbed slowly and peaked about 3 hours after the drink, at 87 ppm after a ketone ester and 44 ppm after ketone salts. The researchers also found that D-BHB, but not L-BHB, was converted to breath acetone. So a breath reading taken 30 minutes after a BHB drink tells you very little about what is in your blood at that moment.

How BHB Supplements Change Each Ketone Body

The Stubbs paper remains one of the most detailed human studies of what happens after you drink exogenous ketones. Fifteen healthy adults drank a ketone ester or a sodium and potassium BHB salt at doses that delivered roughly 12 or 24 g of BHB. Blood D-BHB peaked at 2.8 mM with the ester and 1.0 mM with the salt, and returned to baseline within 3 to 4 hours. The salt was 50% L-BHB, which stayed in the blood for more than 8 hours. Less than 1.5% of the BHB ended up in urine. TΔS Ltd. supplied the ester, and two of the authors are inventors on ketone ester patents held by Oxford and partners.

What one ketone drink did to blood BHB

Blood BHB in mM after a single drink, healthy adults (Stubbs et al., 2017).

Peak D-BHB

Ketone ester drink2.8 mMKetone salt drink (50% D, 50% L)1.0 mM

L-BHB after the salt drink

4 hours after drinking1.1 mM8 hours after drinking0.7 mM24 hours after drinkingUndetectable

Source: Stubbs BJ, et al. Front Physiol. 2017;8:848. Drinks gave about 12 or 24 g of BHB. The L-BHB follow-up used the higher dose in 5 people.

Beyond Raw Chemistry Labs BHB Salts at GNC lists 5 g of goBHB per serving.

Beyond Raw Chemistry Labs BHB Salts, sold at GNC, lists 5 g of goBHB D-BHB per serving, bound to four electrolyte minerals. That is a smaller total dose than either Stubbs drink, so don’t read your own blood levels straight off that chart. For a timeline of how long blood levels stay up, see how long ketones last after a BHB drink.

What Your Ketone Test Is Actually Measuring

Each test sees a different ketone body. Finger-stick blood meters use enzyme strips that read D-BHB; Stubbs needed lab chromatography to see the L form. Urine strips react to acetoacetate, which is why they turned positive in the Holland-Winkler study. Breath meters read acetone, which peaks hours after blood BHB.

CleanForm goBHB powder: 2.5 g D-BHB and 2.5 g L-BHB per scoop.

This matters if your product contains L-BHB. CleanForm’s goBHB powder label lists 2.5 g of D-BHB and 2.5 g of L-BHB per 7.9 g scoop, so a standard blood meter only sees half of what you drank. The CleanForm goBHB Energy Shot is built on L-goBHB, and a D-BHB meter isn’t designed to pick that form up. For the full rundown on meters and strips, read our guide to BHB testing.

The CleanForm goBHB Energy Shot uses L-goBHB with zero caffeine.

Does the Form of BHB Matter?

D-BHB is the form your body makes and burns quickly, while L-BHB is handled more slowly. In a 2025 Japanese trial, 100 analyzed adults with a BMI of 23 to 30 and high visceral fat took 1.5 or 2.9 g/day of D-BHB or placebo for 12 weeks, and visceral fat area fell 10.6 cm² (1.5 g) and 10.9 cm² (2.9 g) versus placebo. Several authors were affiliated with Osaka Gas.

The KETAD trial used racemic D/L salts at 10 g/day for 8 weeks with a calorie deficit of about 500 kcal a day; the BHB group lost 3.05 kg versus 1.51 kg on placebo, a difference that wasn’t statistically significant (p = 0.09). Ketone Labs funded it. Which form works best for a given goal is still open, and goBHB Labs is planning a head-to-head D vs L trial. I explained the two forms in more depth in L-BHB vs D-BHB.

Safety note: BHB salts carry minerals (500 mg of sodium in a scoop of CleanForm goBHB). Check with your doctor first if you have kidney or blood pressure concerns, are pregnant, or take medication.

Where the Evidence Stands

The biochemistry is settled: the liver makes acetoacetate, converts much of it to BHB, and a small share becomes acetone. Human studies show that drinking BHB raises blood D-BHB, acetoacetate and, later, breath acetone, while L-BHB from racemic salts lingers longer. How that translates into long-term outcomes is less clear. The body-composition trials ran only 8 to 12 weeks, and each was funded or co-authored by an ingredient maker, including us. None of these products are meant to treat or prevent any disease.

Frequently Asked Questions

Which ketone body is best for energy?

BHB and acetoacetate are both fuels, and tissues convert BHB back to acetoacetate before burning it. BHB circulates in the largest amount and is the one you can take as a supplement. Acetone is mostly a byproduct.

Is BHB the same thing as ketones?

BHB is one of the three ketone bodies, and usually the most abundant one in blood. When a label says “exogenous ketones,” it almost always means BHB in salt, free acid or ester form.

Why do my urine strips and blood meter disagree?

They measure different molecules. Urine strips detect acetoacetate, blood meters read D-BHB, and breath meters read acetone, which lags behind both.

Do BHB supplements raise acetoacetate?

Yes. In a 2025 crossover study, 7 g of racemic sodium BHB raised plasma acetoacetate by an average of 0.57 mM at 30 minutes, versus 0.07 mM with placebo.

The Bottom Line

Acetoacetate is made first, BHB is the main fuel your blood carries, and acetone is the byproduct you breathe out. A BHB supplement raises BHB directly, and your body turns some of it into the other two. If you test, match the tool to the molecule. For a refresher on how fast your own body makes ketones, see how long to fast for ketosis.

Sources: Stubbs BJ, et al. On the Metabolism of Exogenous Ketones in Humans. Front Physiol. 2017;8:848. Holland-Winkler AM, Moore AR, Bederman I. Effectiveness of Exogenous Ketone Salts in Enhancing Circulating Acetoacetate Levels: A Pilot Study in Healthy Adults. Nutrients. 2025;17(10):1665. Katsuya S, et al. Effect of D-β-Hydroxybutyric Acid on Body Fat in Japanese Adults. Obesities. 2025;5(4):82. Roeth EJ, et al. Effect of Exogenous Ketones as an Adjunct to Low-Calorie Diet on Metabolic Markers. Nutrients. 2025;17:3582. Rahimi N, Gupta S. Biochemistry, Ketogenesis. StatPearls, updated December 2025. Product details from cleanformnutrition.com and Stack3d (Beyond Raw BHB Salts).