Probiotics for Cold Prevention
Cochrane review: probiotics reduced the number of participants experiencing acute URTIs and shortened episodes by ~1–2 days. Effect sizes are modest and strain-specific, but consistent across analyses.
Overview
Verdict
Probiotics modestly reduce upper respiratory infection incidence and duration in meta-analyses.
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- Multi-strain product with Lactobacillus and Bifidobacterium, 10+ billion CFU daily during cold season.
- Expected timeframe
- 4+ weeks of use before season; across a season.
Protocol
- form
- Multi-strain products or specific strains including Lactobacillus rhamnosus GG, Lactobacillus casei Shirota and Bifidobacterium animalis subsp. lactis BB-12 have been used in respiratory infection trials
- duration
- 3-6 months of continuous use across the season - this is preventive, not a treatment for a cold you already have
- co factor
- Take with food. Evidence is mixed but leans positive. A Cochrane review found probiotics were better than placebo at reducing the number of people experiencing acute upper respiratory tract infections, reducing the mean duration of an episode by about a day, and reducing antibiotic use - but the authors rated the evidence quality as low, noted substantial heterogeneity between strains and populations, and many trials were industry-funded. Effects are modest. The mechanism is thought to involve modulation of gut-associated lymphoid tissue, enhanced secretory IgA, and effects on innate and adaptive immune signalling.
- titration
- Up to 20 billion CFU/day; dose is less important than continuous daily use
- starting dose
- 10 billion CFU/day with food, taken daily and continuously
Evidence
Probiotics for preventing acute upper respiratory tract infections
Probiotics may modestly reduce upper respiratory infection episodes, but certainty of evidence is low.
Safety
Caveats
Strain and product quality matter — effects are not universal across formulations. Refrigerated, third-party tested products preferred.
Less likely to help if
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.