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Lactase enzyme

If you can't digest the lactose in dairy (Lactose intolerance), you can either supplement with lactase enzyme pills or consume dairy that's predigested with the lactase enzyme.

Our evidence-based analysis on lactase enzyme features 15 unique references to scientific papers.

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Summary of Lactase enzyme

Primary information, health benefits, side effects, usage, and other important details

What is lactase?

Lactase is an enzyme that breaks lactose down into galactose and glucose. A lack of ability to produce enough lactase is the major reason why people are lactose intolerant. Secondary intolerance can be due to gut health issues. Lactase is frequently added to milk or taken during meals to aid in digesting lactose.

What are lactase's benefits?

Can simply taking lactase as a supplement allow people to digest lactose more effectively? That appears to be the case, as supplementation of lactose proved effective in many human trials, with reductions in breath hydrogen (a sign of fermentation) and various symptoms such as flatulence, bloating, abdominal pain, and diarrhea—the most common symptoms of lactose intolerance.

Simply taking lactase may not necessarily eliminate symptoms, and many of the studies still found that those with lactose interolance still experienced more fermentation when taking lactase than those who weren't lactose intolerant, and had worse symptoms. There's some evidence to suggest that higher doses and milk pretreatment for 24 hours or more are good solutions, and it's probably best to err on the side of a higher dose.

What are lactase's side effects and drawbacks?

We haven't evaluated that yet, but it's not foreign to the body, so the risk is probably low.

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How to Take

Recommended dosage, active amounts, other details

Rules of thumb used to calculate the amount of lactase are 7500 units for 16 grams of lactose (roughly one normal glass of milk), and 3000 units for 5 g, which is similar but higher.

Of these, the latter was more likely to lead to a meantingful reduction when taken orally. This makes sense given the dynamic nature of the digestive tract, so doses of lactase shouldn't be based on the amount needed to hydrolyze lactase, but on in vivo evidence. Other studies generally suggest that less than 3000 units per 5 g leads to less impressive reductions in lactose fermentation.

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Human Effect Matrix

Unlocked for Examine members

The Human Effect Matrix summarizes human studies to tell you what effects Lactase enzyme has on your body, how much evidence there is, and how strong these effects are.

Full details are available to Examine members.
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
grade-c Strong Very High See all 9 studies
Both pretreating milk with lactase and taking lactase during a meal containing lactose tend to lead to a considerable reduction in breath hydrogen. With milk, pretreatment with lactase for 24 hours may lead to somewhat less fermentation than taking it acutely.
grade-c Notable Very High See all 4 studies
Any time symptoms have been harmonized in a single score, lactase had led to a notable reduction, either when milk was pretreated or lactase was taken at mealtime. 24-hour pretreatment seemed to lead to somewhat fewer symptoms than acute consumption.
grade-d Notable Very High See all 3 studies
Both pretreated milk and acute doses of lactase during meals reduced bloating, as could be expected from the reduction in breath hydrogen, indicating less fermentation. It's unclear which is more effective.
grade-d Notable High See all 3 studies
Both lactase supplementation during mealtimes and lactase pretreated milk seemed to notably reduce instances of diarrhea. It's unclear which is more effective.
grade-d Notable Very High See all 4 studies
Both acute lactase supplementation and pretreatment of milk led to notable reductions in flatulence, as could be expected from the reduction in lactose fermentation. It's unclear which is more effective.
grade-d Notable - See study
One study found a notable reduction in insulin resistance when children with obesity and a poorly lactose-digesting genotype were given lactase supplements. The reduction was greater than for a low lactose diet, though the groups were unbalanced at baseline. and the lactase group had more room for improvement.
grade-d Minor High See all 3 studies
Self-reported abdominal pain is notably reduced by both lactase pretreated milk and acute lactase supplementation during a meal. It's unclear which is more effective.
grade-d Minor - See study
In one study, there was a greater reduction of heartburn when consuming lactase milk compared with regular milk, but more high-quality research is needed to confirm this.
grade-d - Moderate See 2 studies
Of the two trials that evaluated headaches, neither had enough instances of headaches to provide meaningful evidence for an effect. More research with more participants is needed.
grade-d - - See study
In one study, there was so little nausea in either group that it's unclear what the effect of lactase might be when used to prevent notable nausea.
grade-d - - See study
There were possible minor reductions in one study, though stool consistency didn't seem to be an issue in either group, so this study can't provide meaningful evidence one way or the other.

Studies Excluded from Consideration

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Click here to see all 15 references.