Beta galactosidase

Enzyme

What is it

Beta-galactosidase (lactase) is a digestive enzyme that breaks down lactose into glucose and galactose. Supplemental forms are used by people with lactose intolerance to help digest dairy.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Lactose intolerance symptoms

Strong Evidence

Multiple RCTs and meta-analyses confirm that beta-galactosidase taken with dairy reduces symptoms of lactose maldigestion (gas, bloating, diarrhea) in lactose-intolerant individuals.

How it works

Endogenous lactase is produced by enterocytes in the small intestine. Lactose intolerance arises when activity declines, and undigested lactose ferments in the colon, causing gas, bloating, and diarrhea. Supplemental beta-galactosidase taken with dairy hydrolyzes lactose in the gut so it can be absorbed normally. Enzyme activity is measured in FCC ALU (Acid Lactase Units) or FCC GalU; product effectiveness depends on units delivered at the same time as the lactose meal.

Dosage

There is no RDA. Typical OTC products provide 3,000-9,000 FCC ALU per dose, taken with the first bite of dairy. DSLD does not provide a median dose for this entry.

When and how to take it

Take immediately before or with the first bite of dairy. Effect is local and short-lived; dose with each lactose-containing meal.

1 commercial form

Compare the main delivery options and what they’re best suited for.

Microbial beta-galactosidase (e.g., from Aspergillus oryzae)

Pills, drops, and chewables are common.

Acts locally in the gut; no systemic absorption required.

Safety

Generally very well tolerated; serious adverse events are rare. Allergic reactions to fungal-source enzymes are possible.

Who should be cautious

Not appropriate for galactosemia (a genetic disorder where galactose accumulates). People with mold or fungal allergies should check the enzyme source.

Interactions

No significant interactions reported.

Frequently asked questions

Can lactase pills cure lactose intolerance?⌄

No. They reduce symptoms when taken with dairy but do not restore endogenous enzyme activity.

How quickly does it work?⌄

It acts during the meal. Take it right before or with the first bite of dairy.

References

Beta galactosidase on Wikidata — Wikidata link

Beta galactosidase on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Beta galactosidase (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.