Supplement

Lactase Enzyme

Lactase is an enzyme your small intestine makes to break down lactose, the main sugar in milk, and supplements supply extra of it. People mostly look at it for lactose intolerance, and the evidence is strongest for bloating, which improved in trials, while abdominal pain also eased with moderate evidence. Those studies were fairly small, with 66 and 85 participants, so the findings are a starting point rather than the final word.

Updated 30 September 2026
How we grade
11 studies cited

Best evidence: Grade A
Conditions studied: 2
Outcomes: 11
Graded outcomes: 1100

Evidence by condition

Strong
Moderate
Limited
Very limited

2 conditions

Lactose Intolerance

Lactose Intolerance: outcomes studied for Lactase Enzyme
Grade	Outcome	Effect	Size	Studies	People
	Bloating Moderate Improvement	Improves (the measure goes down)	Moderate effect		66 people
	Abdominal Pain Small Improvement	Improves (the measure goes down)	Small effect		85 people
	Breath Hydrogen	Improves (the measure goes up)		6 studies	283 people
Studies that measured breath hydrogen Effective reduction of lactose maldigestion in preschool children by direct addition of beta-galactosidases to milk at mealtimePediatrics · PMID 3106927 Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intoleranceBiomed Res Int · PMID 24967391 Dietary manipulation of postprandial colonic lactose fermentation: II. Addition of exogenous, microbial beta-galactosidases at mealtimeAm J Clin Nutr · PMID 3918430 Effect of exogenous beta-galactosidase in patients with lactose malabsorption and intolerance: a crossover double-blind placebo-controlled studyEur J Clin Nutr · PMID 15674309 beta-Galactosidase from Aspergillus niger in adult lactose malabsorption: a double-blind crossover studyAliment Pharmacol Ther · PMID 1543816 Beta-galactosidase tablets in the treatment of lactose intolerance in pediatricsAm J Dis Child · PMID 2122719
	Flatulence	Changes; see studies		4 studies	96 people
Studies that measured flatulence A combination of acid lactase from Aspergillus oryzae and yogurt bacteria improves lactose digestion in lactose maldigesters synergistically: A randomized, controlled, double-blind cross-over trialClin Nutr · PMID 25042846 The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trialEur Rev Med Pharmacol Sci · PMID 20391953 Enzyme replacement therapy for primary adult lactase deficiency. Effective reduction of lactose malabsorption and milk intolerance by direct addition of beta-galactosidase to milk at mealtimeGastroenterology · PMID 6434367 Long-term acceptance of low-lactose milkAm J Clin Nutr · PMID 114042
	Diarrhea Symptoms	Improves (the measure goes down)			66 people
	Headaches	Improves (the measure goes down)			26 people
	Heartburn Symptoms	Improves (the measure goes down)			15 people
	Lactose Intolerance Symptoms	Improves (the measure goes down)			101 people
	Nausea Symptoms	Improves (the measure goes down)			30 people
	Stool Consistency	Improves (the measure goes up)			30 people

Obesity

Obesity: outcomes studied for Lactase Enzyme
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Glycemic Control	Improves (the measure goes up)		1 study	40 people
Studies that measured glycemic control Treatment of lactase deficiency in children's obesity with genotype c/c 13910 of lactase geneWiad Lek · PMID 30796855

Key findings

BloatingLactose IntoleranceImproves (the measure goes down)
Abdominal PainLactose IntoleranceImproves (the measure goes down)

Shop the evidence-backed picks

Third-party tested Lactase Enzyme products, in the forms the graded studies used where we can match them.

Grade A

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Studies cited

11 studies from PubMed

A combination of acid lactase from Aspergillus oryzae and yogurt bacteria improves lactose digestion in lactose maldigesters synergistically: A randomized, controlled, double-blind cross-over trialClin Nutr · PMID 25042846
The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trialEur Rev Med Pharmacol Sci · PMID 20391953
Enzyme replacement therapy for primary adult lactase deficiency. Effective reduction of lactose malabsorption and milk intolerance by direct addition of beta-galactosidase to milk at mealtimeGastroenterology · PMID 6434367
Long-term acceptance of low-lactose milkAm J Clin Nutr · PMID 114042
Effective reduction of lactose maldigestion in preschool children by direct addition of beta-galactosidases to milk at mealtimePediatrics · PMID 3106927
Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intoleranceBiomed Res Int · PMID 24967391
Dietary manipulation of postprandial colonic lactose fermentation: II. Addition of exogenous, microbial beta-galactosidases at mealtimeAm J Clin Nutr · PMID 3918430
Effect of exogenous beta-galactosidase in patients with lactose malabsorption and intolerance: a crossover double-blind placebo-controlled studyEur J Clin Nutr · PMID 15674309
beta-Galactosidase from Aspergillus niger in adult lactose malabsorption: a double-blind crossover studyAliment Pharmacol Ther · PMID 1543816
Beta-galactosidase tablets in the treatment of lactose intolerance in pediatricsAm J Dis Child · PMID 2122719
Treatment of lactase deficiency in children's obesity with genotype c/c 13910 of lactase geneWiad Lek · PMID 30796855