Most cheese contains some lactose, but the amount varies dramatically depending on the type. Hard, aged cheeses like Parmesan and cheddar contain almost none, while fresh cheeses like ricotta and cottage cheese can contain several grams per serving. The difference comes down to how the cheese is made and how long it ages.
Why Cheese Has Less Lactose Than Milk
Cow’s milk contains about 4.6% lactose by weight. During cheesemaking, roughly 98% of that lactose is removed or converted before the cheese ever reaches your plate. This happens through two main processes.
First, when milk is separated into curds (the solid part) and whey (the liquid), most of the lactose leaves with the whey. Lactose dissolves in liquid, so it drains away rather than staying trapped in the cheese solids. Second, the starter bacteria used in cheesemaking feed on whatever lactose remains in the curd, converting it into lactic acid. This fermentation continues during the early stages of aging, steadily lowering the lactose content further.
Some cheese varieties use an additional step. Gouda and Edam, for instance, are made by draining some whey and replacing it with warm water, which washes out even more lactose from the curds before they’re pressed.
Lactose Levels in Aged Cheeses
The longer a cheese ages, the less lactose it contains. Bacteria have more time to consume whatever residual lactose is present, and moisture continues to evaporate, concentrating the protein and fat while leaving almost no sugar behind.
In a standard 40-gram serving (about 1.5 ounces), the numbers are striking:
- Parmesan: 0.0 grams of lactose
- Cheddar: 0.04 grams
- Swiss: 0.04 grams
To put that in perspective, a cup of milk has about 12 grams of lactose. A serving of aged cheddar has roughly 300 times less. Soft-ripened cheeses like Brie and Camembert, despite their creamy texture, also contain only trace amounts of carbohydrate and sugars per 100 grams, because the mold-ripening process and bacterial cultures break down most of the remaining lactose.
Fresh Cheeses Contain Significantly More
Fresh, unaged cheeses are a different story. They skip the long aging period that eliminates residual lactose, and they retain more moisture (and therefore more of the lactose dissolved in that moisture). The ranges per serving are noticeably higher:
- Cottage cheese (½ cup): 0.7 to 4 grams
- Ricotta (½ cup): 0.3 to 6 grams
- Mozzarella (part-skim, low-moisture): 0.08 to 0.9 grams
The wide ranges reflect differences in manufacturing. Some brands drain more whey, some use more active starter cultures, and processing times vary. Low-moisture mozzarella tends to have less lactose than fresh mozzarella because more liquid has been removed. Ricotta, which is actually made from whey rather than curds, can land at the higher end because whey is where most of milk’s lactose ends up in the first place.
What This Means if You’re Lactose Intolerant
Most people with lactose intolerance can handle more lactose than they think. The National Institute of Diabetes and Digestive and Kidney Diseases notes that many people tolerate up to 12 grams of lactose (the amount in a cup of milk) without symptoms or with only mild ones. A serving of aged cheddar or Parmesan, at 0.04 grams or less, is nowhere near that threshold.
Hard, aged cheeses are widely considered safe for people with lactose intolerance. The NIDDK specifically recommends trying “hard cheeses, like cheddar or Swiss, which are lower in lactose than other milk products.” Fresh cheeses like cottage cheese and ricotta are more likely to cause discomfort, though even their lactose content is well below that of a glass of milk. Eating cheese with a meal rather than on its own can also help, since other foods slow digestion and give your body more time to process the lactose.
Lactose-Free Cheese Products
Some manufacturers produce cheeses labeled “lactose-free” by adding the enzyme lactase to the milk before curdling. Lactase breaks lactose into two simpler sugars (glucose and galactose) that don’t cause digestive trouble. This approach is most common with soft cheeses like ricotta and mozzarella, where the natural lactose content would otherwise be higher. Hard cheeses like cheddar and Parmesan sometimes get the same treatment, but it’s less necessary since aging already brings their lactose content close to zero.
If you see a lactose-free label on an aged cheese, the product is legitimate, but you’re often paying a premium for something that was already functionally lactose-free through natural aging.
Does the Milk Source Matter?
Goat, sheep, and cow milk all contain similar percentages of lactose in their raw form. A cheese made from goat milk and aged the same way as one made from cow milk will end up with a comparable lactose level. The belief that goat cheese is inherently easier to digest for lactose-intolerant people is largely a misconception. Any digestive advantage people notice with goat cheese is more likely related to differences in fat structure and protein composition than to lactose content. The same rules apply regardless of milk source: aged means less lactose, fresh means more.