Prebiotics

Do prebiotics help with constipation?

Updated 4 Nov 2026

Short answer

Somewhat, and the evidence conflicts. EFSA, the European food safety agency, concluded in 2015 that 12 g a day of native chicory inulin raises stool frequency, from 6 studies with 86 people.[1] In 2021 it found the evidence insufficient for a similar product, because one trial at 15 g a day had not been repeated.[2]

The newest guideline is more careful. A 2025 British guideline for chronic constipation found that inulin-type fructans softened stools a little and did not raise stool frequency, with low certainty. GOS and polydextrose changed neither.[3] A 2024 review of 37 trials found that lactulose added 3.39 bowel movements a week, with moderate certainty.[4]

In a 2022 review, fiber supplements as a whole helped: 66% responded, against 41% with control, mainly with psyllium and pectin at more than 10 g a day.[5]

Sources (5)

  1. Scientific Opinion on the substantiation of a health claim related to "native chicory inulin" and maintenance of normal defecation by increasing stool frequency. European Food Safety Authority, 2015. www.efsa.europa.eu
  2. Frutalose, a mixture of fructans obtained from enzymatic hydrolysis of chicory inulin, and normal defecation: evaluation of a health claim. European Food Safety Authority, 2021. efsa.onlinelibrary.wiley.com
  3. British Dietetic Association Guidelines for the Dietary Management of Chronic Constipation in Adults. Dimidi E, van der Schoot A, Barrett K, Farmer AD, Lomer MC, Scott SM, et al. J Hum Nutr Diet, 2025. PMID 41081513
  4. Network meta-analysis of probiotics, prebiotics, and synbiotics for the treatment of chronic constipation in adults. Deng X, Liang C, Zhou L, Shang X, Hui X, Hou L, et al. Eur J Nutr, 2024. PMID 38693449
  5. The Effect of Fiber Supplementation on Chronic Constipation in Adults: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials. van der Schoot A, Drysdale C, Whelan K, Dimidi E Am J Clin Nutr, 2022. PMID 35816465

More about prebiotics

What are prebiotics?Do prebiotics change your gut bacteria?How long do prebiotics take to work?Which foods contain prebiotics?What are prebiotics used for?Is a synbiotic better than a prebiotic alone?

For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.