Glass of kefir

Does dairy cause acne?7 minute read

Glass of kefir

New to the series? Read part 1 first.

‘Will cutting out dairy clear my acne?’

Here’s the short answer: it depends. For the long but helpful answer, carry on reading.


Dairy and acne: what does the research say?

As you can read about in The Happy Skin Solution, the dairy-acne connection is far from clear.

The internet is awash with stories of cystic acne clearing after cutting out cow’s milk. But it may surprise you to learn that the claim that dairy causes acne isn’t based on gold-standard research.

The connection is largely based on asking people what they eat (or used to eat), and trying to find a pattern between their food and the severity of their acne. One study asked 47,355 women what they used to eat as teenagers—and found that the more milk they drank, the more likely they were to have acne as a teen [1].

There are a couple of issues with this sort of study:

– People are unreliable. Can you remember what you ate last week, let alone 20 years ago?

– Correlation does not equal causation. If you plot the numbers on a graph, there appears to be a direct correlation between the divorce rate in Maine and the per capita consumption of margarine (really!). It doesn’t mean that one is causing the other—they can just be co-occurring phenomena.

Other research seems to support this last point with regards to dairy and acne. Another study looking at 2,201 adolescents found there was no relationship between dairy consumption and the presence of acne [2].

And yet here the plot thickens. A meta-analysis (which is a fancy word to mean ‘looking at the data from several studies’) found that acne was worse when people drank more milk—but it was no worse when people ate yoghurt or cheese [3]. A 2020 study that looked at more than 24,452 people seemed to point the finger specifically at milk too [4].

So, what’s going on?


Why can dairy cause acne?

Dairy can contribute to acne in different people for different reasons.

You have to remember that studies use statistics to find ‘significant’ trends. One person could react wildly to dairy, while two others could have no issue at all—and when you look at the data, these could balance each other out.

We can use studies to guide us, but it’s just as important to find out what works for you as an individual. And both my research and clinical experience suggest that dairy can cause skin problems in some people.

To understand why, let’s take a brief look at some biological mechanisms:


A sensitivity to milk proteins

You can react to casein or whey found in milk. Unlike a full-blown allergy, a sensitivity is much slower and much more subtle—symptoms could appear days after you eat dairy. This can make it hard to see the connection.

People who react to casein tend to have dramatic results when they cut out dairy, and they usually find they’re fine when eating goat’s or sheep’s dairy (which contain a different form of protein).

People who react to whey often find their acne is worse when they consume lots of whey-based protein powders. It’s often behind the ‘bodybuilder’ acne.


An exaggerated insulin response

Your body releases the hormone insulin whenever you eat. Insulin helps to shuttle glucose (from your broken-down food) out of your blood cells and into your cells.

This is an essential bodily process. But problems can arise when too much insulin is released too often, as it kicks your sebaceous glands up a notch and causes them to produce more oil—leaving you more acne-prone.

So, what causes sharp rises in insulin? Refined carbohydrates and sugar are the main culprits but, surprisingly, so is milk. Not only do milk’s natural sugars cause an insulin response, but its whey and casein also cause the body to produce more [5].

When you combine sugar and dairy, this effect can be exaggerated. That’s why many people find ice cream is a huge acne trigger.


Response to milk microRNAs

‘MicroRNA’ sounds scarily scientific, but it simply means a molecule that interacts with genes.

Cow’s milk contains hundreds of microRNAs. They perform lots of functions, but a key one is to tell the calf’s genes that it’s time to start growth processes [6].

And herein lies the potential problem: cow’s milk is designed to help a calf double its birth weight in 40 days. It may be that the ‘growth signals’ provided by the microRNAs in cow’s milk are too much for an adult human. When a person no longer needs to grow, the signals can run amok—causing the excess skin cell growth and sebum production that lead to acne.

It’s important to note that this research is ‘translational’, which means it’s just providing hypotheses at this stage. But it’s pretty compelling. Cow’s milk may contribute to acne not because you’re drinking loads of cow hormones (which is another popular theory on the internet) but because of how the milk makes your own hormones behave.

These are just a few examples of how milk and dairy interact with your body. Food is information and, as you can see, dairy contains complex messages.


The Happy Skin Solution Cover


What are the worst types of dairy for acne?

So, what does all this science mean for you and your diet?

If you’re currently suffering from acne, it’s worth paying attention to how much cow’s dairy you’re eating. According to the research, some forms are more problematic than others.

Milk seems to be most strongly associated with acne. Interestingly, skimmed or low-fat milk may trigger acne more than full-fat milk [7].

Cheese is next up, though there are differences between the types. Soft cheese (e.g. cream cheese) may be more problematic than hard, aged cheeses (e.g. Parmesan).

Yoghurt appears to be least troublesome of all. This may be because the process of fermentation reduces both the milk sugars and the microRNAs [8]. Interestingly, kefir (fermented milk) has even been found to have a positive effect on acne [9].


Should you cut out dairy?

We’re going to come full circle here: it depends.

The bottom line is that dairy can contribute to acne—but cutting it out won’t lead to a clear complexion in everyone. Acne is a multi-faceted condition, and dairy is often just one piece of the puzzle.

If you want to see if dairy has an effect on your skin, the best thing to do is to cut it out entirely for a period of time. Three months would be ideal, but three weeks can be enough to give an indication too. While you’re eliminating dairy, focus on eating lots of seeds, nuts and pulses to maintain your calcium intake.

After the elimination period, reintroduce dairy products in this order:

1) Butter

2) Fermented milk (kefir)

3) Hard cheese: Parmesan, Grana Padano, mature cheddar

4) Yoghurt

5) Soft cheese: cream cheese, Brie

6) Cream

7) Milk

8) Ice cream

Eat the food three times in one day (i.e. three servings of butter), then wait three days. If your skin doesn’t react, you can eat that food once more. If your skin does react, continue to eliminate it and move to the next type of dairy on the list.

For those types of dairy that you did react to, try eating a sheep or goat’s milk alternative and see if it makes a difference.

In my experience, most people who’ve suffered from acne should avoid making dairy a mainstay of their diet. But they can find a happy equilibrium. Your skin may be fine with hard cheese, but not great after a milky latte. One serving of dairy a day could be OK, but you start to see issues after two.

Experiment and see what works for you. The goal is to make your diet as diverse and relaxed as possible.


For more skin-clearing research and practical tips, get your copy of The Happy Skin Solution.

Related Posts

Dr Thivi Maruthappu


Dr Thivi Maruthappu is the UK’s first and only dual-qualified Consultant Dermatologist and Nutritionist, and the pioneer of the (much-needed!) Nutritional Dermatology field. She runs busy NHS dermatology clinics, conducts academic research and delivers lectures worldwide. She’s also recently authored her first book, Skin Food, which aims to make holistic skincare accessible for everyone.



Porter magazine called her a ‘Global Skincare Expert’, and Caroline Hirons described her as ‘one of the best facialists in the world’. In the skincare industry, Marie Reynolds is in a league of her own. I had the privilege of experiencing one of Marie’s facials as a young journalist—and I can still remember every exquisite detail more than a decade later.

Cherries for Happy Skin From Within

Give your skin a treat

Want the jumpstart guide to eating for great skin (plus updates from me)? No spam, ever, I promise.