Lactase and Alpha-Galactosidase Enzyme Supplements

Two enzymes, two different problems

Enzyme supplements supply an enzyme meant to break down one specific food component. They are not probiotics, and they are not prescription pancreatic enzymes (see digestive enzyme supplements). This page covers the two enzyme types with the clearest published research.

• Lactase breaks down lactose, the sugar in milk and milk products.
• Alpha-galactosidase is aimed at galacto-oligosaccharides, carbohydrates found in beans and some other vegetables that the small intestine cannot digest.

Lactase

What it is. NIDDK (US) describes lactase products as tablets or drops that contain lactase, the enzyme that breaks down lactose. [1] The NHS (UK) says a lactase supplement taken before food or drink containing lactose may reduce or prevent symptoms for some people. [2]

What it cannot do. If lactose intolerance comes from lactase nonpersistence or congenital lactase deficiency, no treatment can increase the amount of lactase the small intestine makes. [1] A supplement works only on the meal it is taken with.

What trials show.

A 2025 narrative review also reports that a low-lactose diet, allowing up to 12 to 15 g of lactose a day, was well tolerated by most people with lactose intolerance. [6] NIDDK likewise says research suggests many people could have 12 grams of lactose, about 1 cup of milk, with no or only mild symptoms. [7]

Who should check first. NIDDK says to check with a doctor before using lactase products and that some people, such as young children and pregnant and breastfeeding women, may not be able to use them. [1] For infants, a 2024 systematic review of five trials (391 infants under 6 months with colic) called the overall evidence for lactase drops inconclusive. [8] Do not give lactase to a baby without a pediatrician's advice.

Nutrition. NIDDK says avoiding all milk and milk products may leave you with less calcium and vitamin D than you need. [7] See calcium, vitamin D and the full guide to lactose intolerance. The longer comparison of the evidence is on lactose intolerance and lactase supplements.

Alpha-galactosidase

• Small trials in people without a diagnosis. A 1994 double-blind crossover trial in 19 adults fed meatless chili found fewer gas events per hour with the enzyme than placebo over 6 hours; the difference was statistically significant only for the fifth hour, and bloating and pain did not differ. [9] A small trial in 8 healthy volunteers eating cooked beans reported less breath hydrogen and less flatulence at the higher enzyme amount studied. [10]
• People with irritable bowel syndrome (IBS). Results differ. One crossover trial found a full enzyme amount reduced overall symptoms in IBS patients who were sensitive to galacto-oligosaccharides. [11] A 12-week trial in 125 IBS patients found no evidence to support routine use. [12] A pilot crossover study in 20 IBS patients found no difference from placebo. [13]
• Strength: mixed. Studies used different enzyme products, amounts and meals, so one result should not be transferred to another product. Details are on alpha-galactosidase, beans and gas.

When gas or bloating needs a check, not a supplement

The NHS says to see a GP if you feel bloated regularly, or have bloating with unintentional weight loss or with blood in your poo. [14] NIDDK advises talking with your doctor before using supplements for gas. [15] See bloating and gas and digestive red flags.