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Moderate evidenceGut health

Bifidobacterium Infantis

Properly B. longum subsp. infantis, this is the strain behind Align and one of the few probiotics with a well-designed dose-finding IBS trial behind it. The evidence is real but modest, single-strain, and largely confined to strain 35624.

What the science says

  • Improves global IBS symptoms (strain 35624) Moderate evidence

    In a 4-week dose-ranging RCT of 362 women with IBS, encapsulated B. infantis 35624 at 100 million CFU/day significantly improved abdominal pain/discomfort and a composite of bloating, bowel dysfunction and quality of life versus placebo, while 10 million and 10 billion CFU/day did not — an unusual inverted dose-response driven by formulation stability. A later multicenter trial in non-patients with bloating found more limited benefit.

  • It is a broadly effective probiotic for gut complaints Limited evidence

    The 2023 Gastroenterology review of 82 probiotic RCTs in IBS rated evidence for individual strains, including 35624, as low certainty, and results outside IBS (bloating in non-patients, inflammatory bowel disease) are inconsistent. It is a reasonable single-strain trial, not a general gut fix.

  • Infant strains colonize breastfed babies and digest HMOs Moderate evidence

    B. infantis is genuinely specialized for human milk oligosaccharides and colonization trials in breastfed infants show durable engraftment while breastfeeding continues, which is the basis for infant products such as EVC001. That biology does not transfer to adults, where it behaves like any other transient probiotic.

  • Effects persist after stopping Limited evidence

    Fecal shedding studies show B. infantis 35624 is cleared within about 1-2 weeks of discontinuation in adults. Continuous daily use is required.

Dosage & safety

Studied doseThe pivotal adult IBS trial used 100 million (1 x 10^8) CFU/day for 4 weeks — notably lower than typical mega-dose probiotics, and higher doses performed worse in that trial. Judge response after 4 weeks and stop if nothing changes. Infant formulations (e.g. EVC001) use far higher counts and are a separate product category.
SafetyWell tolerated, with mild gas or bloating early on. Avoid routine use in severely immunocompromised, catheterized, or critically ill patients due to rare bacteremia reports. Infant probiotic use should be discussed with a pediatrician, particularly for preterm or hospitalized newborns, where FDA has warned about probiotic-associated sepsis.

Scientific references

Where to buy

Align Probiotics, 24/7 Digestive Support, Probiotic Supplement, 28 Capsules

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