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Head-to-head evidence comparison — which supplement is right for you?
Lactase vs L. casei Shirota: Lactase has the stronger overall evidence (5.5 vs 5/10); they're alternatives for improve digestion — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Lactase wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Too few graded studies
Top outcomes
Verdict
Too few graded studies
Top outcomes
Shared outcomes (1)
Outcomes where both Lactase and L. casei Shirota have evidence — compare verdict strength side-by-side.
Taken per lactose-containing meal, not as a daily dose. Trials gave 3,000 to 11,250 units of lactase (mostly FCC units) immediately before or with a single dairy or lactose challenge. One 2022 trial used 4,662 FCC units and describes 4,500 FCC units as the amount in the EU-approved health claim. More lactose needs more enzyme: 50 g of lactose given in water overwhelmed about 6,000 units in one trial. Products differ, so dose by the enzyme units on the label rather than by tablet count.
With meals
Lactase tablets, capsules or chewables labelled in FCC units, taken with dairy
One 65-100 mL bottle of the fermented milk drink daily, delivering roughly 6.5 x 10^9 to 1 x 10^11 CFU depending on the product. Doses across trials span this whole range with no dose-comparison study to separate them.
Any time of day
Fermented milk drink containing L. casei Shirota (Yakult), 65-100 mL daily
Hours (same meal)
Hours (same meal)
Hours (same meal)
Hours (same meal)
4 weeks
2 weeks
2-12 weeks
8 weeks
Systematic review: effective management strategies for lactose intolerance.
Annals of Internal Medicine (2010) · Systematic review
36 randomised trials met the inclusion criteria, 26 of them on lactase- or lactose-hydrolysed milk supplements, lactose-reduced milk, or tolerable doses of lactose.
Effect of lactase supplementation on infant colic: Systematic review of randomized controlled trials.
Journal of Pediatric Gastroenterology and Nutrition (2024) · Meta analysis · n=391
Five randomised trials with 391 infants under 6 months old with colic were included.
The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial.
European Review for Medical and Pharmacological Sciences (2010) · Rct · n=60
60 lactose-intolerant patients were randomised to tilactase taken 15 minutes before a lactose breath test, placebo, or Lactobacillus reuteri twice daily for 10 days beforehand (20 per group).
Efficacy of daily intake of Lactobacillus casei Shirota on respiratory symptoms and influenza vaccination immune response: a randomized, double-blind, placebo-controlled trial in healthy elderly nursing home residents.
Am J Clin Nutr (2012) · Rct · n=737
PRIMARY ENDPOINTS ALL NULL: no effect on days with respiratory symptoms, probability of respiratory symptoms, or post-vaccination antibody titre
Probiotics and synbiotics in chronic constipation in adults: A systematic review and meta-analysis of randomized controlled trials.
Clin Nutr (2022) · Meta analysis
Probiotics overall increased stool frequency (SMD 0.71, 95% CI 0.37-1.04, p<0.00001) — but the effect was driven by Bifidobacterium lactis, 'not mixtures of probiotics, Bacillus coagulans Unique IS2 or Lactobacillus casei Shirota'
A study into the effect of Lactobacillus casei Shirota in preventing antibiotic associated diarrhoea including Clostridioides difficile infection in patients with spinal cord injuries: a multicentre randomised, double-blind, placebo-controlled trial.
EClinicalMedicine (2021) · Rct · n=359
PRIMARY ENDPOINT NULL: antibiotic-associated diarrhoea at 30 days 45% vs 42.1% (RR 1.071, 95% CI 0.8-1.4, p=0.639)
Lactase has a higher evidence score (5.5/10 vs 5/10) and wins in 1 of 3 categories.
For improve digestion, L. casei Shirota has a higher relevance score (52 vs 45).
No known interactions between Lactase and L. casei Shirota have been documented in our database. However, always consult a healthcare provider before combining supplements.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.