Sodium butyrate

What sodium butyrate is

Sodium butyrate is the sodium salt of butyric acid, a short-chain fatty acid with four carbon atoms. In the body, butyrate is produced mainly in the colon when bacteria ferment dietary fiber; there it is an important energy source for the cells of the lining (Hamer 2008). Butyric acid itself smells and tastes unpleasant, so the salt is used for food supplements, often microencapsulated so that it is released further down in the gut.

Related approaches start earlier: prebiotics supply the food from which gut bacteria produce butyrate, among other things, and probiotics supply the bacteria themselves. In the BK-Score, human evidence stands at 4 out of 10 points. This axis rates the state of knowledge, not the substance: small positive studies are a start, not proof.

How it is supposed to work

In experiments, butyrate dampens inflammatory responses, strengthens the protective barrier of the gut lining and reduces oxidative stress. Inhibition of the inflammatory switch NF-kappa-B and inhibition of histone deacetylases are considered important mechanisms. A 2008 review emphasizes, however, that the effects depend heavily on concentration and model and that human data are limited (Hamer 2008).

For capsules, another question arises: where does the butyrate end up? In the Verhaar 2024 blood pressure study, butyrate levels rose in the blood but not in the stool. Testa 2026 points out that consumption in the gut and breakdown in the liver limit how much butyrate reaches the circulation. Butyrate from a capsule and butyrate that bacteria in the colon produce from dietary fiber therefore cannot simply be equated.

What the studies show

Irritable bowel syndrome: individual symptoms less frequent

Banasiewicz 2013 gave 66 patients with irritable bowel syndrome, who had been receiving standard therapy for at least three months, additional microencapsulated sodium butyrate or placebo. After 4 weeks, pain during bowel movements occurred less often, and after 12 weeks so did urgency and irregular bowel habits. Abdominal pain, bloating and defecation disorders did not improve significantly. The authors summarize: individual symptoms occurred less often but did not become markedly weaker.

Ulcerative colitis: as add-on therapy

Karłowicz 2025 treated 98 adults with mild to moderate ulcerative colitis for eight weeks with additional 2 × 300 mg microencapsulated sodium butyrate or placebo. In the butyrate group, 51 percent improved clinically, 31.4 percent achieved clinical and 42.2 percent biochemical remission; the authors report these results as significant. The abstract does not give the rates for the placebo group, and the study is small and short.

Weight: children and adults

Coppola 2022 randomized 54 children and adolescents with obesity to sodium butyrate (20 mg per kilogram of body weight daily) or placebo, in addition to standard treatment over 6 months. The primary endpoint, a BMI reduction of at least 0.25 standard deviations, was reached by 96 percent with butyrate and 56 percent with placebo. Testa 2026 gave 46 overweight adults 1,875 mg daily or placebo for 12 weeks on the same diet. Without diabetes, they lost 7.0 kg with butyrate and 3.2 kg with placebo; with type 2 diabetes, weight did not differ, but triglycerides fell.

Type 2 diabetes with irritable bowel symptoms

Panufnik 2026 gave 52 patients with type 2 diabetes and irritable bowel symptoms 1.5 g microencapsulated sodium butyrate daily or placebo for 12 weeks. In the butyrate group, abdominal pain, diarrhea and bloating decreased, as did weight, HbA1c and the HOMA index; in the placebo group nothing changed significantly. The analysis was mainly within groups, not a direct comparison, and the study was registered only retrospectively.

High blood pressure: blood pressure rose

Verhaar 2024 tested sodium butyrate in 23 people with high blood pressure whose blood pressure medication was stopped for the study; the placebo group received a corresponding amount of table salt. After 4 weeks, daytime blood pressure with butyrate was 9.6 mmHg systolic and 5.1 mmHg diastolic higher than with placebo, even though butyrate had lowered blood pressure in animal experiments. The authors advise caution in further butyrate studies.

Where the data stop

• Substitute for dietary fiber. Whether butyrate from a capsule achieves what dietary fiber does in the colon has not been shown; in the blood pressure study, butyrate content in the stool did not rise.
• Gut health in healthy people. Butyrate is often advertised for this, including against a leaky gut. The studies cited here concern people with bowel or metabolic diseases; a benefit for healthy people has not been demonstrated.
• Long term. The longest study lasted 6 months, most 4 to 12 weeks.
• Size of the studies. All randomized trials cited here had fewer than 100 participants and used different products and amounts.

Status, approval and legal

In Germany, sodium butyrate is sold as a food supplement; it is not a medicine. Sodium butyrate has no entry in the European Commission’s Novel Food Catalogue. For tributyrin, a related butyrate source made of glycerol and three butyric acid residues, a consultation procedure in Poland in 2024 concluded that it is a novel food; it is not authorized. An explicit official classification of sodium butyrate as a food supplement could not be found. There is no authorized health claim for butyrate.

Safety

The data come from studies lasting 4 weeks to 6 months, each with fewer than 100 participants. The most notable signal is the rise in blood pressure in people with high blood pressure. Sodium butyrate consists of about one fifth sodium, which counts on a low-sodium diet. With high blood pressure, butyrate should therefore be discussed with a physician. In the BK-Score, safety data stand at 4 out of 10 points; this axis measures how well safety has been studied, not how safe the substance is. This text is information and does not replace medical advice.

Sources

• Hamer HM et al., Aliment Pharmacol Ther 2008 – review of the role of butyrate in the colon
• Banasiewicz T et al., Colorectal Dis 2013 – microencapsulated sodium butyrate in irritable bowel syndrome, RCT with 66 patients
• Karłowicz K et al., Med Sci Monit 2025 – microencapsulated sodium butyrate as add-on therapy in ulcerative colitis, RCT with 98 patients
• Coppola S et al., JAMA Netw Open 2022 – butyrate in childhood obesity, RCT with 54 children
• Testa R et al., Clin Nutr 2026 – sodium butyrate in overweight with and without type 2 diabetes, RCT with 46 adults
• Panufnik P et al., Sci Rep 2026 – microencapsulated sodium butyrate in type 2 diabetes with irritable bowel symptoms, RCT with 52 patients
• Verhaar BJH et al., Hypertension 2024 – oral butyrate in high blood pressure, RCT with 23 patients
• European Commission, Novel Food Catalogue – tributyrin: novel food not yet authorized (no entry for sodium butyrate)