Propionate and Butyrate

What is it?

Propionate and butyrate (propionic acid and butyric acid) are short-chain fatty acids that healthy gut bacteria make from dietary fiber. Butyrate is the most important energy source for the cells of the gut. In Parkinson's, the very bacteria that produce it are often missing. 2'-fucosyllactose (2FL) is a sugar from breast milk that feeds these bacteria.

What does the research say?

In a randomized, double-blind study, 72 Parkinson's patients received propionate plus butyrate, 2FL, or all of them together for six months, each in delayed-release capsules so the substances only arrive in the large intestine (Scientific Reports).

• In all three groups, motor function improved by at least 5 points on the UPDRS Part III, a clinically relevant amount.
• The need for levodopa dropped by more than 15 percent.
• Thinking also improved in all groups, the sense of smell only in the groups that received 2FL.
• The gut flora itself hardly changed. The effect apparently came from a tighter gut wall and a calmer immune system.
• For constipation, the combination of all three substances did best.

The daily amounts used were 1,200 mg propionate, 2,400 mg butyrate and 3,900 mg 2FL. There was no placebo group, and six months is too short to judge an effect on the course of the disease.

Tributyrin: does butyrate reach the brain?

At the University of Michigan, 14 people with Parkinson's took 500 mg of tributyrin, a precursor of butyrate, three times a day for one month (Neurotherapeutics). Using a new PET method that makes butyrate visible in the body, the researchers showed that after one month more butyrate from the supplement reached the brain. That is remarkable, because for most supplements it has not even been shown that they reach the brain at all. Afterward the participants also did better in tests of memory, gait and coordination, and inflammation markers in the blood fell. However, it was a small study without a placebo group, so the improvements are not proven. Showing that the substance arrives is an important first step, but not yet proof that it works.

New (2026): Hannover Medical School published further results of its study with 72 patients. The combination of 2FL and short-chain fatty acids clearly reduced constipation after six months and improved quality of life, but there was no placebo group (Neurology and Therapy). Since November 2025, BUTTER2 has also been running, the first trial to test tributyrin against placebo: 45 patients with memory problems, 3 × 500 mg a day for 90 days, results in 2027 (ICH GCP, NCT07154511).

Availability

Propionate is available as sodium propionate, butyrate as sodium butyrate (it smells unpleasant) or as the better tolerated tributyrin, and 2FL as a human milk oligosaccharide. Important: Most capsules sold over the counter already dissolve in the small intestine. Their effect may therefore differ a lot from the study products.

My experience

I now take propionate and butyrate every day. My Heilpraktikerin (naturopath), who specializes in the gut, believes my gut microbiome is already in good shape thanks to my earlier transplants and my diet.

My conclusion

An exciting study that shows how closely the gut, the immune system and the brain are connected. A simpler and cheaper way is to feed your own butyrate-producing bacteria: with plenty of fiber from vegetables, legumes and whole grains.