Butyrate

What it does

Butyrate is a short-chain fatty acid made by gut bacteria from fiber fermentation; it fuels colon cells and regulates gut barrier and immune function. Oral butyrate salts are rapidly absorbed in the upper gut, so only delayed-release (microencapsulated) forms plausibly reach the colon, where the evidence sits.

What the research says

• Microencapsulated sodium butyrate reduced IBS abdominal symptoms

  Evidence: emerging. Banasiewicz et al.: 300 mg/day for 12 weeks (n=66 RCT) reduced abdominal pain and defecation symptoms with no adverse events; a 2026 trial at 1.5 g/day in T2D plus IBS improved GI symptoms, HbA1c, and HOMA-IR

• Ordinary oral butyrate has poor colonic bioavailability

  Evidence: moderate. Pharmacokinetic data show rapid upper-GI absorption and metabolism before reaching the colon; microencapsulation is designed to solve this

Small but promising RCTs in IBS, all with microencapsulated forms; most of the evidence is preclinical or animal. Fiber that feeds your own butyrate producers has far stronger support than butyrate capsules.

Is it worth it?

Interesting for IBS, but only in microencapsulated form, and high-fiber foods that feed endogenous butyrate producers are cheaper and better supported. Wait for larger trials.