What Is Lactase?

This supplement can be used as needed to treat lactose intolerance

Lactase capsules, tablets, and chewable tablets

Verywell / Anastasia Tretiak

Lactase is a digestive enzyme involved in the breakdown of lactose, a sugar found in milk and other dairy products. Lactase, produced in the lining of the small intestine, splits lactose into the smaller sugar molecules (known as glucose and galactose) so that it can be digested. If you have lactose intolerance, it is because you are not able to produce enough lactase on your own.

Taking lactase supplements—available in caplet, chewable, and other forms—may reduce or prevent many of the symptoms that can occur when someone with lactose intolerance consumes dairy, including stomach cramps, diarrhea, and gas.

What Is Lactase Used For?

According to a 2019 study published the American Journal of Clinical Nutrition, around 70% of the world's population is lactase deficient, with the highest prevalence being among people of East Asian, West African, Arab, Jewish, Greek, or Italian descent.

On rare occasion, lactose intolerance can occur at birth, a condition referred to as congenital lactase deficiency (CLD). But experts now understand that a gradual decline in one's ability to produce lactase after early childhood is a very common human trait and the more common cause of intolerance.

Fortunately, the majority of people with lactase deficiency never develop symptoms of lactose intolerance. But for those who do, the symptoms can range from mild to significant and typically occur about half an hour to a few hours after eating dairy.

Lactase supplements (taken before meals) may help these individuals consume more dairy, allowing them meet their dietary calcium needs, as well as help them overcome symptoms of lactose intolerance.

However, there is at least some debate about the supplements' effectiveness among patients.

Lactose Intolerance

Despite the benefits of lactase supplements, there remains a paucity of research evidencing their effects. Although scientists agree that the supplements are safe, there has not always been consensus on how well they work.

According to a 2010 study in the European Review for Medical and Pharmacological Sciences, lactase supplements showed clear superiority in alleviating lactose intolerance compared to the probiotic Lactobacillus reuteri.

The 10-day study involving 60 adults showed that a single lactase supplement, taken 15 minutes before a meal, was better able to normalize lactose metabolization (as measured by a lactose breath test) than a 10-day course of L. reuteri. Moreover, lactase supplements were better able to alleviate key gastrointestinal symptoms, especially gas.

Despite the positive findings, a 2014 study in BioMed Research International reported significant variability in the response to lactase supplementation. Of the 96 adults given a lactase supplement, only 21.88% showed complete normalization using the lactose breath test, while 17.71% were fully non-responsive.

This suggests that other factors may contribute to the inability to metabolize lactose or, alternately, that other types of lactase may be needed to metabolize lactose in certain people.

Bone Health

Lactase supplements themselves cannot improve bone health directly. But because they can help lactose intolerant people eat more dairy without consequence, they can make it easier to consume adequate amounts of calcium. This, of course, can help build and maintain healthy bones while reducing the risk of bone loss and osteoporosis.

According to a 2019 study in the journal Nutrients, when those with lactose intolerance avoid or cut back on dairy, they are at risk for bone loss and fractures. But intolerance itself does not significantly affect adults' ability to absorb calcium (the same is true for lactase deficiency).

Everyone—including those with lactose intolerance—are recommended to consume three servings of dairy a day. Lactase supplements can help you get there.

Possible Side Effects

Lactase supplements are considered safe and well-tolerated with no known side effects.

However, people with diabetes need to use lactase supplements with caution. Once ingested, lactase is broken down into simple sugars that can increase your blood glucose level. While this may not cause any significant problems, it is important to check your blood sugar 20 to 30 minutes after taking a dose just to be sure.

On rare occasion, lactase supplements have been known to trigger allergic reactions. In one reported case, a woman who handled lactase supplements for her children but never took them herself experienced a severe, whole-body allergy known as anaphylaxis.

Call 911 or go to your nearest emergency room if you develop hives, rash, shortness of breath, wheezing, dizziness, lightheadedness, rapid heart rate, or swelling of the face, tongue, or throat after taking a lactase supplement.

If left untreated, anaphylaxis can lead to shock, coma, respiratory or heart failure, and death.

Lactase supplements should not be used by women who are pregnant or breastfeeding as there is not enough information to ensure their safety. It is also unknown if lactase supplements can interact with other medications or supplements.

Lactase tablets

Verywell / Anastasiia Tretiak​

Dosage and Preparation

In addition to capsules and chewables, lactase supplements are sold in powder and drop forms. These can be stored safely at room temperate in a sealed container. Never use a supplement past its expiration date.

The standard dose is 6,000 to 9,000 international units (IU) taken immediately before a meal containing dairy. Others have found that adding 2,000 IUs of lactase powder to two cups (500 milliliters) of milk can help mitigate symptoms.

As a general rule, start at a low dose and gradually increase it until you achieve the desired control. Even though you cannot overdose on lactase, taking smaller amounts can reduce the impact on your blood sugar and help you save money.

Always be sure to take a lactase supplement prior to the first bite of dairy. If eating over a duration longer than 20 to 30 minutes (say, at a picnic or banquet), take another 2,000-mg dose during the meal to extend the protective benefit.

However, just because you are taking a lactase supplement doesn't mean you consume dairy with abandon. If you are lactose intolerant, it is important to control your intake, skipping the extra cream, cheese, or milk whenever possible (or, at the very least, cutting back on portions).

What to Look For

Widely available for purchase online, lactase supplements can be found in many natural foods stores, drugstores, and shops specializing in dietary supplements. You do not need a prescription to buy lactase supplements.

Dietary supplements are not strictly regulated by the U.S. Food and Drug Administration (FDA). To ensure quality and safety, look for brands that have been certified by an independent, third-party authority, such as the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab.

Lactase is not derived from dairy, so taking supplements is not a concern if you are vegan. However, the coating that makes up some capsules may be made of animal-derived gelatin. If this is a concern for you, look for products labeled "vegan."

Most lactase supplements are made from a compound called beta-galactosidase derived from the fermentation of the fungi Aspergillus niger or Aspergillus oryzae. Beta-galactosidase is often included in broad-spectrum digestive enzyme supplements, including vegan-friendly products like VeganZyme.

Other Questions

I take lactase supplements, but they don't seem to be helping. Why?
This may be because you are not taking a high enough dose, you are not timing it as advised, or you are consuming more dairy than your body can tolerate—even with supplementation. It is possible that some people may simply need to avoid lactose altogether.

If you are unable to control your symptoms with lactase supplements, ask your healthcare provider for a referral to a gastroenterologist or allergist for further investigation. You may also want to consider if you are actually lactose intolerant. People often diagnose themselves or their children as lactose intolerant when they, in fact, have an allergy to milk.

What are other sources of calcium beyond dairy?
While dairy products are a top source of calcium, it is possible to get ample calcium without them. If lactase supplements aren't effective for you, you can meet the recommended dietary allowance (RDA) of calcium—1,000 milligrams (mg) per day for women ages 18 to 50 and men ages 18 to 70—with these food sources:

  • Kale: 100 mg per cup
  • Bok choy: 74 mg per cup
  • Fortified whole wheat bread: 30 mg per slice
  • Broccoli: 21 mg per 1/2 cup

A daily calcium supplement can also help you meet your need.

Frequently Asked Questions

  • What does a lactose pill do?

    Lactose pills such as Lactaid contain the digestive enzyme lactase, which helps digest lactose, the sugar found in milk and dairy products. People who are lactose intolerant do not make enough lactase to break down this sugar. Supplementing with lactase enzyme helps to prevent symptoms of lactose intolerance. 

  • Do lactase enzyme pills have any side effects?

    On rare occasions, a very serious allergic reaction known as anaphylaxis can occur. If you develop symptoms such as shortness of breath and swelling of the face, tongue, or throat, call 911 or go to the nearest emergency room. In addition, people with diabetes should monitor their blood sugar after taking a lactase supplement as it may raise blood sugar. 

  • Is it safe to take lactase enzyme every day?

    Yes, lactase enzyme supplements such as Lactaid can be taken every day. In fact, it is safe to take lactase with every meal.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Itan Y, Jones BL, Ingram CJ, Swallow DM, Thomas MG. A worldwide correlation of lactase persistence phenotype and genotypes. BMC Evol Biol. 2010 Feb 9;10:36. doi:10.1186/1471-2148-10-36

  2. National Institutes of Health. Lactose Intolerance. Genetics Home Reference. 2019.

  3. Voisin MR, Borici-Mazi R. Anaphylaxis to supplemental oral lactase enzyme. Allergy Asthma Clin Immunol. 2016;12:66. doi:10.1186/s13223-016-0171-8

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