Cart

Your cart is empty

Probiotic

Probiotics

live beneficial microbes

Live microbes that may benefit gut health. Effects depend on the strain and the condition.

Evidence: Moderate

Evidence by use: Moderate for specific uses; strain-specific. NIH summarizes moderate evidence for preventing antibiotic-associated diarrhea (for example Lactobacillus rhamnosus GG or Saccharomyces boulardii), modest benefit in IBS (multi-strain products), limited evidence for atopic dermatitis, and insufficient evidence for Crohn's disease. Obesity benefits are small and of questionable clinical significance.

At a glance

Typical studied dose

Typical supplements contain 1-10 billion CFU per dose; some exceed 50 billion. Dose depends on the strain studied.

Food sources

Animal sources

Fermented dairy: yogurt, kefir.

Plant sources

Fermented vegetables (kimchi, sauerkraut), miso, tempeh (live-culture only).

Background and testing

This is not an essential nutrient, so there is no deficiency to diagnose.

Who tends to use it

People taking antibiotics, those with IBS symptoms, and those seeking digestive support.

How it is tested

No routine test for need. Stool tests that claim to personalize probiotics have limited evidence.

Supplement forms

Common forms

Capsules, powders, gummies, drinks, fermented foods; single-strain or multi-strain; refrigerated or shelf-stable.

More effective

Products listing the exact strain (genus, species, strain ID) that matches the studied use, with a CFU count guaranteed through expiration.

Less effective

Products listing only the species or 'proprietary blend'; CFU counts at time of manufacture only; assuming any probiotic works for any condition.

Safety, interactions and halal notes

Safety and interactions

Generally safe for healthy people; mild gas or bloating possible. Rare serious infections (bacteremia, fungemia) have occurred in vulnerable people. In 2023 the FDA warned about the risk of invasive infection in preterm infants.

Who should avoid it or ask a clinician first

Severely immunocompromised people, ICU patients with central lines, and preterm or very low birth weight infants should not use them without medical direction.

Halal note

Check the growth medium and the capsule or gummy base. Culture media can include animal-derived or alcohol-related ingredients, so look for halal certification of the finished product.

Frequently asked questions

Which probiotic should I choose?

Choose by strain and use. Different strains have different evidence, so match the strain to the goal.

Do probiotics work for everyone?

No. Benefits depend on the strain, the condition and the person.

Sources

Probiotics: Fact Sheet for Health Professionals (NIH ODS)

← Back to the full nutrient guide

This page is for education only and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Supplements are not intended to diagnose, treat, cure or prevent any disease. Talk to a qualified clinician before starting a supplement, especially if you are pregnant, breastfeeding, take medicine or have a medical condition. Daily needs are US reference intakes for adults 19-50.

Share this page