Visceral fat is the fat packed around your organs, deep in the abdomen, and it’s the kind most people never see in the mirror. It’s also the kind researchers care about most, because it tracks with metabolic health markers far more closely than the fat you can pinch. So when people ask me about BHB and visceral fat, they want to know whether anyone has actually measured it in humans.
Researchers have. Two randomized, placebo-controlled trials out of Japan measured visceral fat directly in people taking D-BHB every day for 12 weeks, and an 8-week U.S. trial of BHB salts measured fat mass and hip circumference with DEXA scans and a tape. Here is what each one found, what the doses were, who paid for the work, and how I’d use that information if belly fat were my goal.
Why Visceral Fat Is Measured Differently
You can’t track visceral fat with a bathroom scale. Two people at the same weight can carry very different amounts, and a person can lose a few pounds without changing it much. Researchers measure it with CT or MRI scans, which report visceral fat area in square centimeters (cm²) at the level of the navel, or estimate it with bioimpedance devices that are less precise.
That matters when you read BHB studies. A result reported as CT-measured visceral fat area is a stronger piece of evidence than a change in body weight or waist size, because it looks at the specific fat depot that matters.
The 2023 Trial: 2.9 g of D-BHB a Day for 12 Weeks
The first study, published in the Journal of Nutritional Science and Vitaminology in 2023, randomized healthy Japanese adults to 2.9 g a day of D-BHB or placebo for 12 weeks, with 22 people in each group. Visceral fat in the D-BHB group fell by 9.0 cm², and the comparison with placebo was statistically significant (p = 0.037). Blood work showed no safety differences between groups, and nobody reported side effects.
It was a small trial, and some of the secondary results came from a post-hoc analysis after one participant was excluded. The authors work for Osaka Gas, the company that produces the D-BHB used in the study. Those are fair caveats, and they’re exactly why the follow-up study mattered.
The 2025 Trial: BHB and Visceral Fat at Two Doses
In November 2025, the same group published a larger trial in Obesities. They randomized 108 adults with a BMI of 23 to 30 and a high visceral fat area at screening, and analyzed 100. Participants took 1.5 g of D-BHB, 2.9 g of D-BHB, or placebo every day, two hours before dinner, for 12 weeks. Visceral fat area was measured by CT.
Visceral fat area reduction vs. placebo after 12 weeks
Reported cm² reduction with daily D-BHB; each result was significant vs. placebo.
Sources: Katsuya et al., J Nutr Sci Vitaminol 2023 and Obesities 2025 (linked below). Both trials had Osaka Gas-affiliated authors.
Both doses reduced visceral fat area compared with placebo: by 10.6 cm² on 1.5 g (p = 0.004) and by 10.9 cm² on 2.9 g (p = 0.002). The higher dose also lowered body weight by 1.4 kg and body fat percentage by 1.3 points versus placebo, measured by bioimpedance. No trial-related adverse events were reported.
The interesting part to me is that 1.5 g did about as well as 2.9 g on visceral fat. That is a small amount of BHB, well below what most keto powders put in a scoop. Only the 2.9 g group showed significant changes in body weight and body fat percentage, though. The paper reports no external funding, but four of the six authors are employees of Osaka Gas or its chemicals subsidiary, which supplied the D-BHB. Some secondary results were exploratory, and the study population was Japanese adults who weren’t dieting or exercising regularly.
What the BHB Salt Trial Adds
The third study is one our company, then called Ketone Labs, paid for: an 8-week double-blind trial, published in Nutrients in 2025, in which adults with a BMI of 27 to 35, on a diet about 500 calories below their needs and asked to walk 30 minutes three days a week, took 5 g of racemic BHB mineral salts twice a day (10 g total) or a maltodextrin placebo. The paper reports 24 people on BHB and 27 on placebo.
The BHB group lost 3.05 kg of body weight versus 1.51 kg on placebo, and 1.97 kg of DEXA-measured fat mass versus 0.82 kg. Hip circumference fell 4.6 cm versus 0.8 cm. Those between-group differences were trends, not statistically significant results (p = 0.05 to 0.22), and waist circumference didn’t differ between groups. Visceral fat wasn’t measured. I wrote more about the muscle side of this trial in our post on keeping muscle while losing fat.
D-BHB vs. racemic BHB salts
The Japanese trials used D-BHB, the form your body makes. The salt trial used a D/L blend bound to minerals. Products made with goBHB come in both forms, so check which one is on the label. I covered the differences in D-BHB vs. L-BHB.
How I Would Use BHB for Visceral Fat
If visceral fat is your target, the research points to a consistent daily habit, not a big occasional dose. Both Japanese trials used 1.5 to 2.9 g every day for 12 weeks, and the 2025 trial timed the dose two hours before dinner. The 2025 trial excluded people who were dieting or exercising regularly, but I’d still pair BHB with a modest calorie deficit and regular training, because the salt trial was run on a calorie deficit, and the extra weight and fat loss in the BHB group there trended in the right direction without reaching significance.
Two goBHB products are on shelves now. If you want to match the visceral fat studies, Beyond Raw uses D-BHB, the form those trials tested; CleanForm uses a D/L blend like the salt trial. CleanForm Nutrition goBHB is a 50/50 D/L blend of calcium, magnesium, sodium and potassium BHB, is sold in Unflavored, Tangy Apple and Strawberry Kiwi, and is NSF Certified for Sport. GNC’s Beyond Raw Chemistry Labs BHB Salts deliver 5 g of goBHB D-BHB per serving, unflavored, with 115 mg calcium, 135 mg magnesium, 210 mg sodium and 127 mg potassium. You can read more in our Beyond Raw launch post.
A safety note on salts: every gram of a BHB salt comes with minerals, including sodium. If you watch sodium, have kidney or blood pressure concerns, are pregnant or nursing, or take medication, check with your doctor before adding a daily ketone product.
Where the Evidence Stands
Two randomized trials found that 1.5 to 2.9 g a day of D-BHB reduced CT-measured visceral fat by roughly 9 to 11 cm² over 12 weeks, significantly more than placebo. Both were run by a team tied to the company that makes that D-BHB, and the larger one reported no external funding. A Ketone Labs-funded trial of 10 g a day of BHB salts plus a calorie deficit showed more weight and fat loss than placebo, but as trends rather than statistically significant differences. That is promising, early evidence from three studies, and it needs independent replication. None of these products are meant to treat or prevent any disease.
Frequently Asked Questions
Does BHB reduce belly fat?
Two Japanese trials found daily D-BHB reduced visceral fat area, the deep abdominal fat, by about 9 to 11 cm² over 12 weeks, significantly more than placebo. The studies were small to mid-sized and industry-affiliated, so read the results as encouraging rather than settled.
How much BHB per day for visceral fat?
The trials that measured visceral fat used 1.5 g or 2.9 g of D-BHB a day, and both doses produced similar visceral fat reductions. A separate salt trial used 10 g a day alongside a diet.
How long does BHB take to affect visceral fat?
Visceral fat was measured at 12 weeks in both Japanese trials. Plan on at least three months of daily use before judging results.
Is D-BHB better than BHB salts for fat loss?
No study has compared them head to head for fat loss. The visceral fat data comes from D-BHB, while the salt data comes from a D/L blend at a much higher dose.
The Bottom Line
The human research on BHB and body fat is small, but it’s specific: daily D-BHB at 1.5 to 2.9 g reduced visceral fat measured by CT in two placebo-controlled trials. If that’s your goal, take BHB every day for at least 12 weeks, pair it with sensible eating and training, and pick a product that tells you what form of BHB you’re getting. For dose ranges across other goals, see our goBHB dose guide.
Sources: Katsuya S, Kawata Y, Goto T, Tsubota J. Daily Intake of D-β-Hydroxybutyric Acid (D-BHB) Reduces Body Fat in Japanese Adult Participants: A Randomized, Double-Blind, Placebo-Controlled Study. 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: A Randomized, Double-Blind, Placebo-Controlled Study. 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(22):3582 (funded by Ketone Labs). Product details from CleanForm Nutrition and GNC.