Lactose monohydrate is a type of sugar found in milk.

Due to its chemical structure, it’s processed into a powder and used as a sweetener, stabilizer, or filler in the food and pharmaceutical industries. You may see it on the ingredient lists of pills, infant formulas, and packaged sweet foods.

Yet, because of its name, you may wonder whether it’s safe to consume if you have lactose intolerance.

This article provides a comprehensive overview of the uses and side effects of lactose monohydrate.

Lactose monohydrate is the crystalline form of lactose, the main carb in cow’s milk.

Lactose is composed of the simple sugars galactose and glucose bonded together. It exists in two forms that have different chemical structures — alpha- and beta-lactose (1).

Lactose monohydrate is produced by exposing alpha-lactose from cow’s milk to low temperatures until crystals form, then drying off any excess moisture (2, 3, 4).

The resulting product is a dry, white or pale yellow powder that has a slightly sweet taste and smells similar to milk (2).


Lactose monohydrate is created by crystallizing lactose, the main sugar in cow’s milk, into a dry powder.

Lactose monohydrate is known as milk sugar in the food and pharmaceutical industries.

It has a long shelf life, slightly sweet taste, and it’s highly affordable and widely available. What’s more, it easily mixes with numerous ingredients.

As such, it’s commonly used as a food additive and filler for drug capsules. It’s primarily used for industrial purposes and not typically sold for home use. Thus, you may see it on ingredient lists but won’t find recipes that call for it (5).

Fillers like lactose monohydrate bind to the active drug in a medication so that it can be formed into a pill or tablet that can be easily swallowed (6).

In fact, lactose in some form is used in over 20% of prescription medications and over 65% of over-the-counter drugs, such as certain birth control pills, calcium supplements, and acid reflux medications (4).

Lactose monohydrate is also added to infant formulas, packaged snacks, frozen meals, and processed cookies, cakes, pastries, soups, and sauces, as well as several other foods.

Its primary purpose is to add sweetness or act as a stabilizer to help ingredients that don’t mix — such as oil and water — stay together (7).

Finally, animal feed often contains lactose monohydrate because it’s a cheap way to increase food bulk and weight (8).


Lactose monohydrate may be added to animal feed, medications, baby formulas, and packaged desserts, snacks, and condiments. It acts as a sweetener, filler, or stabilizer.

The Food and Drug Administration (FDA) considers lactose monohydrate safe for consumption in the amounts present in foods and medications (9).

However, some people have concerns about the safety of food additives. Even though research on their downsides is mixed, some have been linked to adverse effects. If you prefer to stay away from them, you may want to limit foods with lactose monohydrate (10, 11).

What’s more, individuals with severe lactose intolerance may wish to avoid or limit their intake of lactose monohydrate.

People with this condition don’t produce enough of the enzyme that breaks down lactose in the intestines and may experience the following symptoms after consuming lactose (12):

  • bloating
  • excessive burping
  • gas
  • stomach pain and cramps
  • diarrhea

While some have suggested that lactose-containing medications could cause unpleasant symptoms, research suggests that people with lactose intolerance can tolerate the small amounts of lactose monohydrate found in pills (13, 14, 15).

However, if you have this condition and are taking medications, you may wish to speak with your medical provider about lactose-free options, as it may not always be clear whether a drug harbors lactose.

Finally, some individuals may be allergic to the proteins in milk but can safely consume lactose and its derivatives. In this case, it’s still important to consult a healthcare professional to ensure that products with lactose monohydrate are safe for you.

If you’re concerned about lactose monohydrate in food, be sure to carefully read food labels, especially on packaged desserts and ice creams that may use it as a sweetener.


While lactose monohydrate is considered safe for most people, consuming it in excess may cause gas, bloating, and other issues for those with lactose intolerance.

Lactose monohydrate is a crystallized form of milk sugar.

It’s commonly used as a filler for medications and added to packaged foods, baked goods, and infant formulas as a sweetener or stabilizer.

This additive is widely considered safe and may not cause symptoms in those who are otherwise lactose intolerant.

However, those with severe lactose intolerance may wish to avoid products with this additive to be safe.