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Digestion & Oral health Q&As

How long should a course of probiotics last?

Taking probiotics is a natural way of reducing infection, fighting inflammation and improving digestion. But how long should you take them for?
illustration of probiotic bacteria
Rédaction Supersmart.
2019-09-12Commentaires (0)

Probiotics are living microorganisms (bacteria and yeasts) which are beneficial to health. They are found in yogurt, in fermented drinks such as kefir and kombucha, and of course, in probiotic supplements. These supplements are primarily formulated to rebalance the body’s microbiota which can be disrupted by factors such as antibiotics, poor diet and illness. They are thus extremely popular for reducing troublesome digestive symptoms like bloating, constipation, gas and stomach-ache.

However, the scientific community very quickly realised that probiotics’ effects on the body were much more extensive. They release substances which inhibit the development of pathogens, stimulate the immune system, interact with the nervous system in the gut, and combat chronic inflammation.

The recommended duration of probiotic treatment depends on the health problem being addressed..

Irritable bowel syndrome (IBS), diarrhea and digestive problems

According to clinical studies that have investigated digestive problems (1-3), between one and three months’ treatment is required to produce improvements in digestion. Here, the probiotics are normally taken with water first thing in the morning on an empty stomach, 15-20 minutes before breakfast.

The probiotic recommended: Probio Forte (5 different probiotic species)


Clinical studies suggest that a period of four weeks is sufficient (4-5) and that the probiotics should normally be taken 30 minutes after breakfast or another meal.

The probiotic recommended : Bifidobacterium longum (strain BB536)

Side-effects of antibiotics and chemotherapy

Studies show it’s best to start taking probiotics as soon as you begin antibiotic treatment or chemotherapy (6-9). The probiotics should be ingested at least two hours after the antibiotics, and supplementation should continue for an average of one to two weeks after antibiotic treatment has finished. These benefits are among the most widely scientifically-documented effects, producing significant reductions in the risk of diarrhea and digestive problems.

The probiotic recommended: Lactobacillus rhamnosus (strain CNCM I-2745)

Traveller’s diarrhea

A three-week course of treatment is recommended if you are travelling within the same geographical region. If you’re moving between different regions, treatment should be extended.

The probiotic recommended: Saccharomyces boulardii

Winter infections and stimulation of the immune system

You have two options here (10-12): you can either take probiotics from autumn through to the end of winter (for six months from November to May) or you can start taking them for a period of two weeks as soon as someone in your household goes down with a winter ailment.

The probiotics recommended: Bifidobacterium longum (strain BB536) and Bacillus subtilis 60 mg (strain I-2745)

Supporting weight loss

Several preliminary studies (13-15) have shown that certain probiotic strains such as Lactobacillus gasseri can help reduce visceral and subcutaneous abdominal fat. Here, treatment generally lasts for three months, accompanied by a low-calorie diet. Supplements should be taken 30 minutes before a meal.

The probiotic recommended: Lactobacillus gasseri

Mood problems, depression

Recent studies show that some probiotic strains help reduce mood problems, depression, anxiety and levels of cortisol (the stress hormone) as a result of their ability to both decrease intestinal inflammation and communicate with the brain via the vagus nerve (16-18). The recommended length of treatment is between four and six weeks and the probiotics should ideally be taken with breakfast.

The probiotic recommended: Lactoxira (eight psychobiotic strains)

Skin problems

Certain Lactobacillus probiotics help reduce inflammation in the various skin layers. They strengthen the intestinal barrier, modulate the immune system and increase production of anti-inflammatory cytokines. Two to three months is generally the right duration.

The probiotic recommended: Derma Relief (4 strains + vitamins B2, E and C + fructo-oligosaccharides)

Reducing blood cholesterol levels

Strains such as Lactobacillus reuteri are recommended for cardiovascular health because of their ability to reduce levels of LDL-cholesterol in the blood (19-20). For optimal results, a course of at least two months is recommended, though some researchers have found benefits from treatment lasting as much as 12 months. The supplements should ideally be taken with breakfast and dinner.

The probiotic recommended : Lactobacillus reuteri

How to make probiotic supplementation as effective as possible


  1. Sisson, Ayis & Bjarnason, Randomised clinical trial: a liquid multi‐strain probiotic vs. placebo in the irritable bowel syndrome – a 12 week double‐blind study, https://doi.org/10.1111/apt.12787
  2. De Chambrun, Neut, Chau et al. A randomized clinical trial of Saccharomyces cerevisiae versus placebo in the irritable bowel syndrome, https://doi.org/10.1016/j.dld.2014.11.007
  3. Majeed et al. Bacillus coagulans MTCC 5856 supplementation in the management of diarrhea predominant Irritable Bowel Syndrome: a double blind randomized placebo controlled pilot clinical study, Nutrition Journalvolume 15, Article number: 21 (2016)
  4. Eskesen et al. Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial, DOI: https://doi.org/10.1017/S0007114515003347
  5. Ojetti et al. The effect of Lactobacillus reuteri supplementation in adults with chronic functional constipation: a randomized, double-blind, placebo-controlled trial. J Gastrointestin Liver Dis. 2014 Dec;23(4):387-91. doi: 10.15403/jgld.2014.1121.234.elr.
  6. Suez, Zmora et al. Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMT, DOI: https://doi.org/10.1016/j.cell.2018.08.047
  7. Hempel, et al (2005), Probiotics for the Prevention and Treatment of Antibiotic-Associated Diarrhea, A systematic review and meta-analysis. JAMA. 307 (18) : 1959-1969.
  8. Johnston, et al (2012). Probiotics for the Prevention of Clostridium difficile–Associated Diarrhea: A Systematic Review and Meta-analysis, DOI: 10.7326/0003-4819-157-12-201212180-00563
  9. Kabbani, et al. Prospective randomized controlled study on the effects of Saccharomyces boulardii CNCM I-745 and amoxi.-clavulanate or the combination on the gut microbiota of healthy volunteers, GUT MICROBES 2017, VOL. 8, NO. 1, 17–32, http://dx.doi.org/10.1080/19490976.2016.1267890
  10. Berggren et al, Randomised, double-blind and placebo-controlled study using new probiotic lactobacilli for strengthening the body immune defence against viral infections. Eur J Nutr. 2011 Apr;50(3):203-10. doi: 10.1007/s00394-010-0127-6. Epub 2010 Aug 28.
  11. Leyer et al. Probiotic Effects on Cold and Influenza-Like Symptom Incidence and Duration in Children, doi: 10.1542/peds.2008-2666
  12. Gerasimov et al. Role of short-term use of L. acidophilus DDS-1 and B. lactis UABLA-12 in acute respiratory infections in children: a randomized controlled trial, European Journal of Clinical Nutrition volume 70, pages463–469 (2016)
  13. Kadooka et al. Regulation of abdominal adiposity by probiotics (Lactobacillus gasseri SBT2055) in adults with obese tendencies in a randomized controlled trial. Eur J Clin Nutr. 2010 Jun;64(6):636-43. doi: 10.1038/ejcn.2010.19. Epub 2010 Mar 10.
  14. Kadooka et al. Effect of Lactobacillus gasseri SBT2055 in fermented milk on abdominal adiposity in adults in a randomised controlled trial. Br J Nutr. 2013 Nov 14;110(9):1696-703. doi: 10.1017/S0007114513001037. Epub 2013 Apr 25.
  15. Sanchez et al. Effect of Lactobacillus rhamnosus CGMCC1.3724 supplementation on weight loss and maintenance in obese men and women. Br J Nutr. 2014 Apr 28;111(8):1507-19. doi: 10.1017/S0007114513003875. Epub 2013 Dec 3.
  16. Bercik et al (2011). The anxiolytic effect of Bifidobacterium longum NCC3001 involves vagal pathways for gut–brain communication, doi: 10.1111/j.1365-2982.2011.01796.x
  17. Pinto-Sanchez et al (2017). Probiotic Bifidobacterium longum NCC3001 Reduces Depression Scores and Alters Brain Activity: A Pilot Study in Patients With Irritable Bowel Syndrome, DOI: https://doi.org/10.1053/j.gastro.2017.05.003
  18. Messaoudi et al (2011). Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects, DOI: https://doi.org/10.1017/S0007114510004319.
  19. Jones et al. Cholesterol lowering and inhibition of sterol absorption by Lactobacillus reuteri NCIMB 30242: a randomized controlled trial, European Journal of Clinical Nutritionvolume 66, pages1234–1241 (2012)
  20. DiRienzo, Effect of probiotics on biomarkers of cardiovascular disease: implications for heart-healthy diets, Nutrition Reviews® Vol. 72(1):18–29


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