Probiotics

Do probiotics help with depression and anxiety?

Updated 4 Nov 2026

Short answer

Reviews found less depression and anxiety, but the trials are mixed and many have limits. A 2025 review covered 23 trials with 1401 people with a diagnosis. With up to 8 weeks of use, it found a substantial drop in depression symptoms and a moderate drop in anxiety symptoms. The results differed widely between trials.[1] A larger 2025 review of 72 trials, which also included prebiotics, synbiotics and people with chronic disease or healthy people with symptoms, found smaller drops. Its authors said that the high variation and limited quality call for larger trials.[2]

The effect varied by group, duration and type of probiotic, so these results do not apply to every strain.[2] Both reviews describe probiotics as a possible addition to usual treatment.[1][2] See stress and mood.

Sources (2)

  1. Effects of Prebiotics and Probiotics on Symptoms of Depression and Anxiety in Clinically Diagnosed Samples: Systematic Review and Meta-analysis of Randomized Controlled Trials. Asad A, Kirk M, Zhu S, Dong X, Gao M Nutr Rev, 2025. PMID 39731509
  2. The efficacy of probiotics, prebiotics, and synbiotics on anxiety, depression, and sleep: a systematic review and meta-analysis of randomized controlled trials. Zhang J, Zhu L, Meng Q, Wang Z, Zhu H BMC Psychiatry, 2025. PMID 41310510

More about probiotics

What are probiotics?Do probiotics change your gut bacteria?Is a higher CFU count better?Which foods contain probiotics?What are probiotics used for?Do probiotics prevent diarrhea from antibiotics and C. difficile?

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