Milk and acne: skim, whole and what studies show

Cow's milk has more research behind a link to acne than any other food. The link shows up in dozens of studies and in three reviews that pooled them. It also has limits that matter when you decide what to drink. This guide gives more detail than Skinli's overview, does diet cause acne, and looks only at milk: which types, how much, what the studies cannot prove, and how to test milk on your own skin. It is part of Skinli's acne diet guide.

The studies behind the milk link

Almost all milk and acne research is observational. Researchers ask people what they drink, then compare the answers with who has acne. A study like this can find a link. It cannot show that milk causes the acne, because people who drink more milk may differ in other ways, such as what else they eat.

No trial has given one group milk and another group no milk and then counted spots. The 2024 acne guideline from the American Academy of Dermatology (AAD), published in the Journal of the American Academy of Dermatology, looked for trials like this. It found the evidence insufficient to make a recommendation on a low-dairy diet for acne.

These are the largest studies:

Study	Who	What it found
Nurses' Health Study II, 2005	47,355 US women recalling their high school diet	2 or more glasses of skim milk a day: 44 percent more likely to have had severe teenage acne
Growing Up Today Study, 2006	6,094 US girls aged 9 to 15	The girls who drank the most milk of every type were more likely to have acne
Growing Up Today Study, 2008	4,273 US boys aged 9 to 15	Skim milk linked to acne; whole and 2 percent milk were not
Danish study, 2018	20,416 adults aged 20 to 96	No link between milk and acne

The two studies of children were prospective: the children reported their diet, and acne was asked about a year or more later. The study of women relied on memory of meals eaten years before, and the women themselves reported whether a doctor had diagnosed severe acne.

Skim, low-fat and whole milk

The AAD says all types of cow's milk, whole, low-fat and skim, have been linked to acne. Skim milk tends to show the strongest link.

Three reviews pooled the studies:

• A 2018 review in Nutrients combined 14 studies of 78,529 people aged 7 to 30. Compared with people who drank no milk, the odds of acne were 22 percent higher for whole milk and 32 percent higher for low-fat or skim milk.
• A 2018 review in the Journal of the European Academy of Dermatology and Venereology combined 13 studies of 71,819 people. It found 24 percent higher odds for skim milk, 14 percent for low-fat milk and 13 percent for full-fat milk.
• A 2019 review in Clinical Nutrition found higher odds for total milk, low-fat milk and skim milk when it compared the highest and lowest intakes.

Why would skim milk show a stronger link? The authors of the 2018 Nutrients review offer a simple reason: people who choose low-fat or skim milk may drink more of it than people who choose whole milk. The researchers behind the boys' study suggest that skim milk contains hormones, or substances that affect the body's own hormones, in amounts large enough to have an effect. Neither explanation has been tested directly.

Why milk might affect skin

The AAD says it is still unclear why milk may worsen acne. Its one theory is that some hormones in milk cause inflammation inside the body, and inflammation can clog pores.

A 2021 review in the American Journal of Clinical Dermatology describes a second idea. Milk makes the body release a large amount of insulin, whatever its fat content. Insulin raises a growth hormone called IGF-1, and IGF-1 can push the skin to make more oil. Around 80 percent of the protein in cow's milk is casein and 20 percent is whey. The review says whey drives most of the insulin rise, while casein raises IGF-1 more. That is one reason researchers look at whey protein shakes as well, covered in whey protein and acne.

This explanation also fits a pattern in the research. The same review says cheese has a low insulin score, while ice cream has a high one because of its added sugar.

Studies that found no link

Some studies found no link, and those results are worth knowing.

The Danish study of 20,416 adults used two methods. It compared milk drinkers with people who drank no milk. It also used a gene that lets adults digest milk sugar: people with the gene tend to drink more milk, so the gene works as a stand-in for lifelong milk intake. Neither method showed a link with acne. The study was in adults, and most acne research is in teenagers.

Two studies of Chinese adults found the opposite of the usual result. In 3,888 people in Singapore, frequent milk drinkers were less likely to have moderate or severe acne. In 1,840 people in Malaysia, eating breakfast foods most days, including milk, cereal and butter, was linked to less acne. A 2026 study of 386 people found no link between dairy intake and acne severity or scarring once other factors were taken into account.

A fair reading is that milk is linked to acne in many groups of young people in Western countries, and the size of that link is modest. The 2018 Nutrients review warns that its results need caution, because the studies differ from each other and there are signs that studies with no link were less likely to be published.

Cheese, yogurt and ice cream

Here the sources disagree:

• The AAD says no studies have found that yogurt or cheese lead to more breakouts.
• The 2019 Clinical Nutrition review found no link between yogurt or cheese and acne.
• The 2018 Nutrients review found 36 percent higher odds of acne with yogurt, and a borderline 22 percent for cheese.

Ice cream shows up more often. Milk chocolate combines milk, sugar and cocoa, and its own trials are covered in chocolate and acne. A 2012 study of 88 Malaysian young adults found that those with acne ate ice cream and drank milk more often, and their diets raised blood sugar more. For how sugar and fast-rising blood sugar fit in, see high glycemic foods and acne.

Plant milks

Many people with acne switch to soy, almond or oat milk. A search of PubMed, the US medical research database, on 26 September 2026 found no study that tested any of these drinks against acne. The milk studies above tested cow's milk only. A plant milk with added sugar adds to the sugar you drink, which matters for the reasons in the glycemic guide.

How much milk

The 2018 Nutrients review looked at amounts. Compared with less than one glass a week, it found:

Amount	Change in odds of acne
2 to 6 glasses a week	No clear link
1 glass a day	41 percent higher
2 or more glasses a day	43 percent higher

These numbers describe groups of people. They cannot tell you what one glass will do to your own skin, and acne has many other causes. The NHS lists hormone changes, some medicines and greasy skin or hair products among them.

What the guidelines say

• AAD, 2024 guideline: evidence is insufficient to recommend a low-dairy diet for acne.
• NICE, NG198: tell people there is not enough evidence to support specific diets for treating acne. The NICE committee also raised a concern that close attention to food can lead to eating disorders in young people.
• AAD, public advice: watch whether a food or drink seems to trigger a breakout, and see what happens without it for a day, a week or a month.

How to test milk on your own skin

If you drink milk every day and think it affects your skin, a short test gives you better information than guessing:

1. Take a photo of your skin in the same place and light, before you start. The progress tracker keeps photos in date order.
2. Stop cow's milk for a month, the longest period the AAD names. Keep cheese and yogurt the same, so you test one thing.
3. Keep your acne routine the same. The acne skincare routine guide explains why skin needs 8 to 12 weeks to show a change.
4. Compare the photos. If you add milk back, keep taking photos so you can see any change.

Removing all dairy is a bigger change, and it is one to plan with a doctor or a registered dietitian.

Diet on its own rarely clears acne. The AAD says keeping skin clear needs acne-friendly skincare and acne medicine as well. For a routine built from a photo of your skin, analyze your skin. See a doctor if your spots are deep, painful or leaving scars.