Does Skim Milk Contain Lactase? A Guide to Lactose in Dairy

January 12, 2026 •

4 min read

According to the U.S. Food and Drug Administration, no indigenous lactase enzyme is present in regular milk, whether whole or skim. The short answer to the question, "Does skim milk contain lactase?" is a definitive and resounding no. Skim milk is simply whole cow's milk with the fat removed, not the lactose.

Quick Summary

Skim milk does not contain the enzyme lactase; like all regular dairy milk, it naturally contains the milk sugar lactose, which can cause digestive issues for intolerant individuals. The removal of fat does not affect its lactose content, and lactase is only added to create lactose-free dairy products.

Key Points

Skim Milk Contains Lactose: The process of making skim milk removes fat, but not the natural milk sugar, lactose.
No Natural Lactase: Like all regular milk, skim milk does not naturally contain the lactase enzyme needed for digestion.
Lactose-Free Milk is Processed: Lactose-free dairy products are specifically treated with an added lactase enzyme to break down lactose.
Lower Fat Does Not Mean Lower Lactose: Skim milk's low-fat content is unrelated to its lactose level, which is similar to whole milk.
Consider Alternatives for Intolerance: People with lactose intolerance should choose lactose-free products or use lactase enzyme supplements rather than skim milk.

The Fundamental Difference: Lactose vs. Lactase

To understand why skim milk does not contain lactase, it is crucial to differentiate between these two similar-sounding terms. While they are related to dairy digestion, they are fundamentally different substances with opposite functions.

What is Lactose?

Lactose is the natural sugar found in milk and other dairy products. It is a complex disaccharide composed of two simpler sugars, glucose and galactose. All regular cow's milk—full-fat, reduced-fat, and skim—contains lactose unless specifically processed to remove it. A standard 8-ounce serving of regular cow's milk contains about 12 to 13 grams of lactose.

What is Lactase?

Lactase is the enzyme produced by the human small intestine that is responsible for breaking down lactose into its two simpler, more easily digestible parts. A person with lactose intolerance has a deficiency of this enzyme, meaning their body cannot properly digest the lactose found in dairy. Instead, the undigested lactose travels to the large intestine, where it is fermented by bacteria, causing symptoms like bloating, gas, and diarrhea.

The Composition of Skim Milk

Skim milk, also known as non-fat milk, is produced from whole milk through a process that removes the milkfat. This is typically done using a high-speed centrifuge, which separates the lighter fat globules from the denser milk fluid.

The key point is that this process only removes the fat, leaving the water-soluble lactose sugar behind. The lactose content remains largely the same as in whole milk. In fact, by volume, skim milk can sometimes have a slightly higher concentration of lactose because the fat has been removed. The notion that lower fat automatically means lower lactose is a widespread misconception.

Why Skim Milk Isn't 'Lactose-Reduced'

Fat is not sugar: The process targets fat, not lactose. Separating the creamy milkfat from the liquid portion has no impact on the carbohydrate (lactose) content.
Higher lactose proportion: Since the fat component is removed, the remaining solids-not-fat, which include lactose and protein, constitute a larger proportion of the final volume.

Creating Lactose-Free Milk: The Industrial Process

For those who are lactose intolerant, the solution is not to drink skim milk, but to opt for lactose-free milk. This product is created specifically for easier digestion and is very different from regular skim milk.

How Lactose-Free Milk is Made

Adding the enzyme: Lactose-free milk is made by adding the lactase enzyme to regular cow's milk during processing.
Predigestion: The added lactase breaks down the lactose into glucose and galactose before it's consumed, effectively doing the work the body's digestive system can't.
Sweeter taste: Because glucose and galactose are perceived as sweeter than lactose, lactose-free milk often has a slightly sweeter taste than regular milk, though its nutritional profile is otherwise identical.

Comparison: Skim vs. Whole vs. Lactose-Free Milk

To clarify the differences, this table outlines the key characteristics of three common milk types:


Feature	Skim Milk (Fat-Free)	Whole Milk	Lactose-Free Milk (Various Fat Levels)
Lactase Content	No (Naturally Present)	No (Naturally Present)	Yes (Added During Processing)
Lactose Content	High	High	No or Trace Amounts
Fat Content	Very Low (<0.5%)	High (>3.25%)	Varies (e.g., non-fat, 2%, whole)
Best For	Lowering fat and calorie intake	Richer texture and taste, more fat-soluble vitamins	Individuals with lactose intolerance
Perceived Flavor	Thinner, less creamy taste	Richer, creamier texture and taste	Slightly sweeter taste

Solutions for Managing Lactose Intolerance

If you have lactose intolerance but want to enjoy dairy, there are several effective strategies beyond simply switching to skim milk:

Consider Lactase Supplements

Over-the-counter lactase enzyme tablets can be taken just before consuming dairy products to help the body break down lactose.
Lactase drops can also be added directly to regular milk to create your own lactose-reduced milk at home.

Explore Naturally Lower-Lactose Dairy

Hard Cheeses: Aged, hard cheeses like Cheddar and Parmesan contain very little to no lactose because the lactose is converted during the aging process.
Yogurt with Live Cultures: The bacteria in some yogurts can help break down lactose, making it easier to digest.

Use Plant-Based Alternatives

For a completely dairy-free experience, milk substitutes like almond, soy, and oat milk are excellent, naturally lactose-free options.

Conclusion

In summary, skim milk does not contain the enzyme lactase and is not a suitable option for those with lactose intolerance. It contains a similar amount of lactose as other types of regular dairy milk. Lactase is an enzyme produced in the human body to digest the natural sugar lactose, and the industrial process to create lactose-free milk involves adding this enzyme. For those managing lactose intolerance, the best course of action is to choose specifically labeled lactose-free dairy products, consider lactase supplements, or explore plant-based alternatives. Consulting with a healthcare provider can also help determine the best dietary strategy for individual needs.

For more information on the safety of milk products, refer to the U.S. Food and Drug Administration.

Frequently Asked Questions

No, skim milk does not have less lactose than whole milk. Both contain similar amounts of lactose, as the skimming process only removes fat, not the milk sugar.

Lactose-free milk is made by adding the enzyme lactase to regular milk, which breaks down the lactose into simpler, more digestible sugars before you drink it.

No, people with lactose intolerance should not assume they can drink skim milk. It contains lactose and can cause the same digestive distress as whole milk. Lactose-free or plant-based alternatives are better choices.

Skim milk does not inherently taste sweeter. However, lactose-free milk does taste sweeter because the added lactase breaks down the lactose into sweeter-tasting sugars.

Yes, lactase drops can be added to regular milk to help break down the lactose over a period of time, creating your own lactose-reduced dairy product.

Lactose-free milk is still a dairy product and contains milk proteins (like casein and whey), so it is not suitable for individuals with a cow's milk allergy. They should choose a non-dairy, plant-based milk alternative.

Most mammals produce lactase as infants to digest their mother's milk. However, many lose the ability to produce sufficient lactase after childhood, leading to lactose intolerance.