Lactobacillus acidophilus

Tier 2 — promising · Gut · Vaginal health · Cholesterol

L. acidophilus is among the most widely consumed probiotic species globally, with over 50 years of clinical research, though evidence is often for multi-strain products rather than L. acidophilus alone. The PRIMAL 2024 RCT (618 preterm infants, JAMA Pediatrics, PMID 39102225), using a multi-strain product including La-5, showed improved gut microbiome eubiosis without increasing infection risk. Alharbi 2024 (PMID 38458507) found L. acidophilus alone did not prevent traveller's diarrhoea but contributed when combined with other strains. The most supported single-strain evidence is for La-5…

Dose: 1–10 billion CFU/day. Specific strains with individual evidence: La-5 (Bifidobacterium animalis subsp. lactis BB-12 co-formulation) and NCFM (standalone). Multi-strain products containing L. acidophilus are the most common commercial form.