Lactase Drug Interactions, Uses, Effectiveness, Safety & More

Lactase is a digestive enzyme. Your body naturally makes it in the lining of the small intestine, where it breaks down lactose, the main sugar found in milk and dairy products.

Many people make less lactase as they get older. When there is not enough lactase, undigested lactose moves into the large intestine, where it can cause gas, bloating, cramps, and diarrhea. This is called lactose intolerance.

Lactase supplements are made from yeasts or fungi grown in the lab, not from a plant. They are sold as tablets, chewables, capsules, and liquid drops. People take them with dairy foods, or add the drops to milk, to help digest lactose more comfortably.

Lactose is a disaccharide, meaning it is made of two smaller sugars joined together: glucose and galactose. Your body cannot absorb lactose until it is split into these two parts.

The lactase enzyme does this splitting. When you take a lactase supplement with dairy, the added enzyme breaks the lactose down in your gut so the simple sugars can be absorbed normally. This lowers the amount of undigested lactose that reaches the large intestine, which is what causes the gas, bloating, and diarrhea.

Because lactase works in the digestive tract and is not meant to be absorbed into the bloodstream, its effect stays mostly in the gut.

Lactase supplements are generally considered safe for most people when used as directed. They have been widely used for many years.

People with a known allergy to molds, yeasts, or fungi should be careful, since the enzyme is often made from these sources. If you have any allergy to the product ingredients, do not use it.

For pregnancy and breastfeeding, there is not much formal research. The enzyme acts mostly in the digestive tract, so the risk is likely low, but to be safe you should check with your doctor or pharmacist before using it regularly.

Lactase is sometimes given to children for lactose intolerance, but you should talk to a pediatrician before using it in young children, especially infants.

Side effects from lactase are uncommon and usually mild. Some people may notice mild stomach upset or cramps.

Allergic reactions are rare but possible, since the enzyme comes from yeast or fungi. Stop using the product and seek medical care if you notice a rash, itching, swelling, trouble breathing, or other signs of a serious allergic reaction.

Keep in mind that lactase does not always fully remove symptoms, so you may still have some gas or bloating if you eat a lot of dairy.

There is no single official dose for lactase. The amount of enzyme is usually measured in FCC lactase units, and different products contain different strengths.

In general, lactase is taken right before or with the first bite of a dairy-containing food or drink. With liquid drops, you can add them to milk and let it sit as directed on the label. If you eat a large amount of dairy, you may need more than one dose, but do not exceed the label directions.

Because products differ, the best approach is to follow the product label and ask your pharmacist if you are not sure how much to take. Start with the smallest amount that controls your symptoms.