A review on the effect of Probiotic Supplementation on Anxiety and Stress Levels

Fatin Nur Suhaila binti Md Rawi; Nur Hanaan binti Asyraf; Nurul Izeti Nadirah binti Mohd

Authors

Fatin Nur Suhaila binti Md Rawi Faculty of Pharmacy, University Sultan Zainal Abidin, Terengganu, Malaysia
Nur Hanaan binti Asyraf Faculty of Pharmacy, University Sultan Zainal Abidin, Terengganu, Malaysia
Nurul Izeti Nadirah binti Mohd Faculty of Pharmacy, University Sultan Zainal Abidin, Terengganu, Malaysia

Keywords:

Probiotics, Anxiety, Stress, Gut-Brain Axis, Psychobiotics, Randomized Controlled Trials, Mental Health, Clinical Efficacy

Abstract

Anxiety and stress show a crucial global psychological burden that needs effective clinically management ways. The purpose of this article review is to quantitatively evaluate the effectiveness of probiotic supplementation in lowering anxiety and stress scores in human clinical trials. PubMed/Medline, Scopus, Frontier, and Google Scholar were systemically queried for studies of this topic that were published from 2017 until 2025. The randomized controlled trials (RCT) and a double-blind, placebo-controlled trial that was written in English were included. The specific combinations of MeSH terms and keywords was used to search the studies of this topic. The current review summarized clinical evidence of thirty-five randomized and non-randomized trials in the study of the impact of probiotic supplementation on anxiety and stress levels. In general, about two-thirds (23 out of 35) of the studies indicated a positive outcome of probiotics on at least one stress or anxiety-related outcome and a third (12 studies) showed no significant effect after the administration of probiotics. These results imply that probiotics can have small psychological advantages, especially to people with mild to moderate stress or subclinical anxiety. The current review summarised clinical evidence of thirty-five studies examining the effects of probiotic supplementation on anxiety and stress levels. Most studies showed some small-scale positive changes in subjective stress, trait anxiety, mood reactivity or other facets of psychological outcomes, especially in those with mild to moderate symptoms. Altogether, it can be concluded that existing literature indicates that probiotics can bring about some small-yet-significant effects on stress and anxiety, but the evidence is still not conclusive. Future research should therefore aim at identifying distinct mechanistic pathways, identifying the best strains, dosage, and duration.

References

Rahmannia M, Poudineh M, Mirzaei R, Aalipour MA, Amir, Goudarzi M, et al. Strain-specific effects of probiotics on depression and anxiety: a meta-analysis. Gut Pathog. 2024;16(1):1–15. https://doi.org/10.1186/s13099-024-00634-8

Sliwka A, Polak-Berecka M, Zdybel K, Zelek-Molik A, Waśko A. Psychobiotics in Depression: Sources, Metabolites, and Treatment—A Systematic Review. Nutrients. 2025;17(13):2139. https://doi.org/10.3390/nu17132139

Shokr MM, Eladawy RM, Azar YO, Raish SMA. Probiotics and the Gut–Brain Axis: Emerging Therapeutic Strategies for Epilepsy and Depression Comorbidity. Foods. 2025;14(17):2926. https://doi.org/10.3390/foods14172926

Asad A, Kirk M, Zhu S, Dong X, Gao M. Effects of prebiotics and probiotics on symptoms of depression and anxiety in clinically diagnosed samples: systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2024;83(7):e1504–20. https://doi.org/10.1093/nutrit/nuae177

Zhang N, Zhang Y, Li M, Wang W, Liu Z, Xi C, et al. Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta‐analysis based on randomized controlled trials. Brain Behav. 2020;10(9):e01699. https://doi.org/10.1002/brb3.1699

Merkouris E, Mavroudi T, Miliotas D, Tsiptsios D, Serdari A, Christidi F, et al. Probiotics’ Effects in the Treatment of Anxiety and Depression: A Comprehensive Review of 2014–2023 Clinical Trials. Microorganisms. 2024;12(2):411. https://doi.org/10.3390/microorganisms12020411

Akkasheh G, Kashani-Poor Z, Tajabadi-Ebrahimi M, Jafari P, Akbari H, Taghizadeh M, et al. Clinical and metabolic response to probiotic administration in patients with major depressive disorder: A randomized, double-blind, placebo-controlled trial. Nutrition. 2016;32(3):315–20. https://doi.org/10.1016/j.nut.2015.09.003

Ma T, Jin H, Kwok LY, Sun Z, Liong MT, Zhang H. Probiotic consumption relieved human stress and anxiety symptoms possibly via modulating the neuroactive potential of the gut microbiota. Neurobiol Stress. 2021;14:100294. https://doi.org/10.1016/j.ynstr.2021.100294

Romijn AR, Rucklidge JJ, Kuijer RG, Frampton C. A double-blind, randomized, placebo-controlled trial of Lactobacillus helveticus and Bifidobacterium longum for the symptoms of depression. Aust N Z J Psychiatry. 2017;51(8):810–21. https://doi.org/10.1177/0004867416686694

Chahwan B, Kwan S, Isik A, Van Hemert S, Burke C, Roberts L. Gut feelings: A randomised, triple-blind, placebo-controlled trial of probiotics for depressive symptoms. J Affect Disord. 2019;253:317–26. https://doi.org/10.1016/j.jad.2019.04.097

Walden KE, Moon JM, Hagele AM, Allen LE, Gaige CJ, Krieger JM, et al. A randomized controlled trial to examine the impact of a multi-strain probiotic on self-reported indicators of depression, anxiety, mood, and associated biomarkers. Front Nutr. 2023;10:1219313. https://doi.org/10.3389/fnut.2023.1219313

Michael DR, Coates N, Kerry-Smith J, John DA, Hulme E, Owen L, et al. Probiotic supplementation improves well-being and anxiety in healthy women: An exploratory, randomized, double-blind, placebo-controlled study. Gut Microbes Rep. 2025;2(1):2543125. https://doi.org/10.1080/29933935.2025.2543125

Rudzki L, Ostrowska L, Pawlak D, Małus A, Pawlak K, Waszkiewicz N, et al. Probiotic Lactobacillus Plantarum 299v decreases kynurenine concentration and improves cognitive functions in patients with major depression: A double-blind, randomized, placebo controlled study. Psychoneuroendocrinology. 2019;100:213–22. https://doi.org/10.1016/j.psyneuen.2018.10.010

Casertano M, Dekker M, Valentino V, De Filippis F, Fogliano V, Ercolini D. Gaba-producing lactobacilli boost cognitive reactivity to negative mood without improving cognitive performance: A human Double-Blind Placebo-Controlled Cross-Over study. Brain Behav Immun. 2024;122:256–65. https://doi.org/10.1016/j.bbi.2024.08.015

Nishida K, Sawada D, Kuwano Y, Tanaka H, Rokutan K. Health Benefits of Lactobacillus gasseri CP2305 Tablets in Young Adults Exposed to Chronic Stress: A Randomized, Double-Blind, Placebo-Controlled Study. Nutrients. 2019;11(8):1859. https://doi.org/10.3390/nu11081859

Ahmad SR, AlShahrani AM, Kumari A. Effects of Probiotic Supplementation on Depressive Symptoms, Sleep Quality, and Modulation of Gut Microbiota and Inflammatory Biomarkers: A Randomized Controlled Trial. Brain Sci. 2025;15(7):761. https://doi.org/10.3390/brainsci15070761

Salleh RM, Kuan G, Aziz MNA, Rahim MRA, Rahayu T, Sulaiman S, et al. Effects of Probiotics on Anxiety, Stress, Mood and Fitness of Badminton Players. Nutrients. 2021;13(6):1783. https://doi.org/10.3390/nu13061783

Grant AD, Erfe MCB, Delebecque CJ, Keller D, Zimmerman NP, Oliver PL, et al. Lactiplantibacillus plantarum Lp815 decreases anxiety in people with mild to moderate anxiety: a direct-to-consumer, randomised, double-blind, placebo-controlled study. Benef Microbes. 2025;16(1):1–12. https://doi.org/10.1163/18762891-bja00073

Patterson E, Griffin SM, Ibarra A, Ellsiepen E, Hellhammer J. Lacticaseibacillus paracasei Lpc-37® improves psychological and physiological markers of stress and anxiety in healthy adults: a randomized, double-blind, placebo-controlled and parallel clinical trial (the Sisu study). Neurobiol Stress. 2020;13:100277. https://doi.org/10.1016/j.ynstr.2020.100277

Guan Y, Zhu R, Zhao W, Wang L, You L, Zeng Z, et al. Effects of Lacticaseibacillus paracasei K56 on perceived stress among pregraduate students: a double-blind, randomized, placebo-controlled trial. Front Nutr. 2025;12:1544713. https://doi.org/10.3389/fnut.2025.1544713

Slykerman RF, Li E. A randomized trial of probiotic supplementation in nurses to reduce stress and viral illness. Sci Rep. 2022;12(1):14742. https://doi.org/10.1038/s41598-022-19104-9

Wu SI, Kao KL, Lin CJ, Lin YJ, Lin IC, Chen WL. Effect of lacticaseibacillus paracasei PS23 on anxiety and sleep difficulties among office workers: a double-blind, randomized controlled pilot trial. Ann Gen Psychiatry. 2025;24(1):59. https://doi.org/10.1186/s12991-025-00599-1

Lee HJ, Hong JK, Kim JK, Kim DH, Jang SW, Han SW, et al. Effects of Probiotic NVP-1704 on Mental Health and Sleep in Healthy Adults: An 8-Week Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients. 2021;13(8):2660. https://doi.org/10.3390/nu13082660

Talbott SM, Talbott JA, Stephens BJ, Oddou MP. Effect of Coordinated Probiotic/Prebiotic/Phytobiotic Supplementation on Microbiome Balance and Psychological Mood State in Healthy Stressed Adults. FFHD. 2019;9(4):265. https://doi.org/10.31989/ffhd.v9i4.599

Boehme M, Rémond-Derbez N, Lerond C, Lavalle L, Keddani S, Steinmann M, et al. Bifidobacterium longum subsp. longum Reduces Perceived Psychological Stress in Healthy Adults: An Exploratory Clinical Trial. Nutrients. 2023;15(14):3122. https://doi.org/10.3390/nu15143122

Johnson KVA, Steenbergen L. Probiotics reduce negative mood over time: the value of daily self-reports in detecting effects. npj Ment Health Res. 2025;4(1):10. https://doi.org/10.1038/s44184-025-00123-z

Slykerman RF, Hood F, Wickens K, Thompson JMD, Barthow C, Murphy R, et al. Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial. EBioMedicine. 2017;24:159–65. https://doi.org/10.1016/j.ebiom.2017.09.013

Skowrońska A, Gawlik-Kotelnicka O, Margulska A, Strzelecki D. The Influence of Probiotic Supplementation on the Severity of Anxiety and Depressive Symptoms; Function and Composition of Gut Microbiota; and Metabolic, Inflammation, and Oxidative Stress Markers in Patients with Depression—A Study Protocol. Metabolites. 2023;13(2):182. https://doi.org/10.3390/metabo13020182

Morales-Torres R, Carrasco-Gubernatis C, Grasso-Cladera A, Cosmelli D, Parada FJ, Palacios-García I. Psychobiotic Effects on Anxiety Are Modulated by Lifestyle Behaviors: A Randomized Placebo-Controlled Trial on Healthy Adults. Nutrients. 2023;15(7):1706. https://doi.org/10.3390/nu15071706

Ben Othman R, Ben Amor N, Mahjoub F, Berriche O, El Ghali C, Gamoudi A, et al. A clinical trial about effects of prebiotic and probiotic supplementation on weight loss, psychological profile and metabolic parameters in obese subjects. Endocrino Diabet & Metabol. 2023;6(2):e402. https://doi.org/10.1002/edm2.402