BHB Free Acid vs BHB Salts: What the Studies Actually Used

Most people buying a ketone supplement never check what the BHB is attached to, and they should. BHB free acid and BHB salts both deliver beta-hydroxybutyrate, but a salt pairs the BHB with a mineral and the free acid has none. That one difference changes the taste, the sodium on the label, and which studies actually apply to the product in your hand.

I’ve formulated with goBHB® for years, and this is one of the questions brand buyers ask me most. Full disclosure: goBHB Labs supplies the goBHB in both products pictured here. Below: what each form is, what the human trials used, the mineral math on a real scoop, and where each one fits.

What BHB Free Acid and BHB Salts Actually Are

Beta-hydroxybutyrate is a ketone your liver makes when you fast or cut carbs. As a raw material it shows up two ways. A BHB salt is BHB bound to a mineral, usually sodium, potassium, calcium or magnesium. That makes it a stable, mild-tasting powder that mixes easily, which is why most keto powders use it.

BHB free acid is the molecule on its own, with no mineral partner. It’s a liquid or syrup, it tastes sharply sour, and it has to be diluted or buffered in a finished product. The upside: you get the ketone without the mineral load. The downside is taste and handling, which is why free acid has been rarer on shelves.

D, L and racemic

Both forms come as D-BHB (the form your body makes), L-BHB, or a 50/50 racemic mix of the two. Salt or acid tells you whether the BHB carries a mineral. D, L or racemic tells you which mirror image of the molecule you’re getting. They’re separate questions, and a label should answer both. I covered the second one in L-BHB vs. D-BHB: the two ketones.

Beyond Raw Chemistry Labs BHB Salts, sold at GNC, uses goBHB as a calcium, magnesium, sodium and potassium salt.

What the Human Trials Used

This is where the form matters most, because you can’t borrow results from a study that used something different from what you’re taking.

BHB salts: the KETAD trial

The longest salt trial in our library is KETAD, published in Nutrients in November 2025 by Roeth and colleagues. Overweight adults on a roughly 500-calorie daily deficit took 5 g of racemic BHB mineral salts twice a day (10 g a day, 24 people) or a placebo (27 people) for 8 weeks. The BHB group lost 3.05 kg vs. 1.51 kg on placebo, a trend that missed statistical significance (p = 0.09), and 1.97 kg of fat mass vs. 0.82 kg, a difference that wasn’t significant. Hip circumference dropped 4.6 cm vs. 0.8 cm. Blood pressure, heart rate, and liver and kidney markers didn’t change. Ketone Labs, my company, funded the study.

D-BHB acid: the Japanese trials

The Katsuya trials from Japan used D-β-hydroxybutyric acid, the form named in their titles, at much lower doses. In the 2023 study, 2.9 g a day for 12 weeks lowered visceral fat by 9.0 cm² more than placebo in 44 healthy adults. The larger 2025 trial in Obesities analyzed 100 adults and found 1.5 g and 2.9 g a day both cut visceral fat area (by 10.6 and 10.9 cm² vs. placebo). Both studies were small, used bioimpedance, and came from authors affiliated with Osaka Gas, which makes the ingredient.

Free D-BHB safety: the Mexico City study

The main free acid tolerability study is a 2023 paper in BMJ Nutrition, Prevention & Health by Pimentel-Suarez and Soto-Mota. Twenty-four healthy adults drank 10 g of free D-BHB diluted in a full liter of water every morning for 4 weeks. Nobody developed acid-base or electrolyte abnormalities on venous blood gases. Side effects followed 6.2% of the 720 drinks, none rated severe, and the most common was stomach discomfort (19 reports, 2.6%). American Ketone and MedPHA donated the product, and the authors declared no competing interests.

Daily BHB dose in human trials, by form

Grams of BHB per day used in each published study.

D-BHB acid, low dose (Katsuya 2025)1.5 gD-BHB acid (Katsuya 2023, 2025)2.9 gFree D-BHB, safety study (Pimentel-Suarez 2023)10 gRacemic BHB salts, KETAD (Roeth 2025)10 g

Sources: the studies linked at the end of this article.

How the Forms Compare in the Blood

A 2017 Oxford study by Stubbs and colleagues in Frontiers in Physiology is one of the few human studies that tracked both D- and L-BHB after a racemic salt. Matched for BHB, a ketone ester pushed blood D-BHB to 2.8 mM and a sodium/potassium salt reached 1.0 mM. The salt was about half L-BHB, which standard meters don’t read, and in the higher-dose salt group L-BHB was still at 0.7 mM eight hours later. Several authors had ties to the ester’s maker.

So a racemic salt gives you a modest D-BHB bump plus a long L-BHB tail. A pure D-BHB acid skips the L half and the minerals, so gram for gram more of what you swallow is the D form. I haven’t seen a published head-to-head of free acid vs. salts at matched doses, and I’d rather say that than guess at the curve. For the hour-by-hour picture with salts, see How Long Do Ketones Last?

The Mineral Math on a Real Scoop

The minerals are where salts deserve a closer look. Beyond Raw Chemistry Labs BHB Salts lists these minerals with every 5 g serving of goBHB:

Mineral per 5 g goBHB servingAmountSodium210 mgMagnesium135 mgPotassium127 mgCalcium115 mgTotal minerals587 mg

For most people that’s a feature. Those are the electrolytes you lose in sweat and in the first days of a low-carb diet, and I like them in a training product. But double the dose to match KETAD’s 10 g and you’re at 420 mg of sodium a day, about 18% of the 2,300 mg Daily Value. If your doctor has you limiting sodium or potassium, that number matters more than the ketone. I went deeper on this in BHB Salts Side Effects.

CleanForm Nutrition goBHB uses a 50/50 D/L blend of calcium, magnesium, sodium and potassium BHB and is NSF Certified for Sport.

Which Form Fits Which Product

I’d pick salts for powders, pre-workouts and hydration products. They taste mild, they’re stable, the minerals are useful for people who train, and the multi-week body composition trial (KETAD) used them. CleanForm Nutrition goBHB (a 50/50 D/L blend) and Beyond Raw are good examples.

Free acid makes more sense in drinks and in any product where the mineral load is the problem, such as a ready-to-drink can you might have twice a day or a formula for someone counting sodium. The Japanese trials also used the acid form, at 1.5 to 2.9 g a day. The trade-off is flavor work, since the acid is sour and needs buffering or real dilution. We’ve also planned the next step ourselves: goBHB Labs has designed an open-label crossover in 30 adults comparing 7 g of L-BHB with D-BHB free acid on ketone levels, glucose, satiety and acid-base markers. The study hasn’t started, so there are no results yet.

Where the Evidence Stands

Salts raise blood D-BHB modestly (Stubbs 2017), and both forms were well tolerated in the trials above. The salt data includes an 8-week randomized trial at 10 g a day with a non-significant trend toward more weight loss than placebo. The acid data includes two small 12-week Japanese trials on visceral fat at 1.5 to 2.9 g a day and a 4-week safety study at 10 g a day with no acid-base problems. All of them are short, most are industry-linked, and none compared free acid with salts directly.

FAQ

Is BHB free acid better than BHB salts?

Not across the board. Free acid avoids the mineral load and the published acid trials used D-BHB, while salts taste better, mix easily and supply electrolytes. I haven’t seen a published matched head-to-head, so “better” depends on the product and the person.

Is BHB free acid safe?

In the 2023 Mexico City study, 10 g of free D-BHB a day for 4 weeks caused no acid-base or electrolyte abnormalities in 24 healthy adults, and none of the reported symptoms were severe. It’s sour, so it was diluted in a liter of water. People who are pregnant, on medications, or managing kidney problems should check with their doctor first.

How much sodium is in BHB salts?

It depends on the blend. Beyond Raw BHB Salts lists 210 mg of sodium per 5 g serving of goBHB, alongside magnesium, potassium and calcium. Check the label, because some salts lean much harder on sodium.

The Bottom Line

BHB free acid and BHB salts both deliver BHB, but the products differ in minerals and in D/L content. Salts bring minerals that help in training products and add up for anyone counting sodium. Free acid drops the minerals but needs dilution and has fewer finished products behind it. Match the form to the study you’re leaning on, read the D, L and mineral lines on the label, and you’ll know what you’re buying. For the ester side of this debate, see Ketone Salts vs. Ketone Esters.

Sources: Roeth EJ, et al. Effect of Exogenous Ketones as an Adjunct to Low-Calorie Diet on Metabolic Markers. Nutrients. 2025;17(22):3582 (funded by Ketone Labs). Katsuya S, et al. Daily Intake of D-β-Hydroxybutyric Acid (D-BHB) Reduces Body Fat in Japanese Adult Participants. J Nutr Sci Vitaminol. 2023;69(2):121-128. Katsuya S, et al. Effect of D-β-Hydroxybutyric Acid on Body Fat in Japanese Adults. Obesities. 2025;5(4):82. Pimentel-Suarez LI, Soto-Mota A. Evaluation of the safety and tolerability of exogenous ketosis induced by orally administered free beta-hydroxybutyrate in healthy adult subjects. BMJ Nutr Prev Health. 2023;6(2):122-126. Stubbs BJ, et al. On the Metabolism of Exogenous Ketones in Humans. Front Physiol. 2017;8:848. Product details from cleanformnutrition.com and the Beyond Raw BHB Salts label.