Does Keto Help Acne? What the Skin Research Shows

For decades the medical line was that chocolate and chips had nothing to do with spots, and anyone who insisted otherwise was told it was a myth. That confidence has quietly crumbled. There is now trial evidence that the type of carbohydrate you eat changes how your skin behaves, and plenty of people who have cut carbs report clearer skin as a side benefit they were not expecting. Here is what the research actually supports, what it does not, and how to think about keto if breakouts are the thing you want to fix.

Does keto cause a breakout first?

This one catches people off guard, so it is worth addressing before the good news. A fair number of people notice their skin gets slightly worse in the first two or three weeks of keto before it settles. It is often called a “purge”, though that word oversells it. The likely causes are mundane: the hormonal churn of switching fuel sources, the water and mineral shifts of early adaptation, and sometimes a jump in dairy or nut intake as people reach for convenient keto foods. If your skin flares at the very start, that is not a sign keto is wrong for you. Give it a month before you judge, keep your other skin habits steady, and see where things land once your body has adjusted.

The study that put diet back on the table

The most cited piece of evidence is a randomised controlled trial by Smith and colleagues, published in the American Journal of Clinical Nutrition in 2007. Young men with acne were assigned to either a low-glycaemic-load diet, lower in sugar and refined starch, or a normal diet, and followed for twelve weeks. The low-glycaemic group saw their lesion counts drop roughly twice as much as the control group. They also lost a little weight and, importantly, improved their insulin sensitivity. That last finding is the thread that ties the whole thing together, because it points at the mechanism rather than just the outcome.

Why blood sugar and insulin drive breakouts

The connection between food and skin runs through hormones, not grease on your fingers. Fast carbohydrate, the sugary drinks, white bread and sweets that spike blood sugar quickly, pushes up insulin and a related messenger called IGF-1. Both of these do three unhelpful things to skin: they tell the oil glands to produce more sebum, they encourage the cells lining your pores to overgrow and clog, and they stoke the low-grade inflammation that turns a blocked pore into a red, sore spot. Eat in a way that keeps blood sugar and insulin on an even keel and you turn the volume down on that entire cascade. A low-glycaemic diet does this, and keto, being very low in fast carbohydrate, does it more firmly still.

The dairy complication

Here is the wrinkle worth knowing about, because keto and dairy tend to travel together. Several observational studies link milk, and skimmed milk in particular, to more acne in some people. The suspected reason is that dairy nudges the same insulin and IGF-1 signalling, and milk also carries hormones of its own. This does not mean cheese and butter will wreck your skin; the signal is strongest for liquid milk and whey, and many people tolerate full-fat dairy without any bother at all. But if you have gone keto, leaned hard on cheese and cream, and your skin has not improved the way you hoped, dairy is the obvious variable to test. Cut it back for a few weeks and watch. Our guide to dairy on keto and going dairy-free covers how to do that without losing the fat you need.

How long before your skin changes?

Skin is slow, and patience is the thing most people underestimate. A single pimple takes weeks to form beneath the surface before it ever appears, so a diet change cannot show up overnight. In the Smith trial the meaningful difference emerged over twelve weeks, and that is a reasonable window to hold in mind. Expect little in the first fortnight, possibly even the small early flare mentioned above, then a gradual calming over the following two to three months. Judging the whole experiment after ten days is the commonest mistake and the surest way to give up just before it would have worked.

What to eat for clearer skin on keto

The part of the evidence that is rock solid is the value of cutting the high-glycaemic offenders, and keto handles that for you by default. Beyond simply removing sugar, a few choices stack the odds in your favour. Build meals around protein, non-starchy vegetables and whole-food fats rather than heavily processed “keto” snacks, since ultra-processed food and its additives are not doing your skin any favours. Keep an eye on hidden sugars in sauces and dressings; our piece on reading labels and spotting hidden carbs is useful here. Oily fish, eggs and leafy greens bring the zinc, omega-3s and vitamin A that skin genuinely uses. And if constant sugar cravings are what pulls you off track, managing those cravings is half the battle for your skin as well as your waistline.

Keto or just a low-glycaemic diet?

It is fair to ask whether you need full keto at all. The honest answer is that the strongest trials tested low-glycaemic eating, not strict ketosis, and keto sits at the far end of that same spectrum. A 2024 review of ketogenic and low-glycaemic diets for inflammatory skin conditions reached a measured verdict: the approach is promising and mechanistically sensible, but keto-specific skin trials are still thin. So if the idea of full keto feels like a lot just for your complexion, a moderate low-glycaemic diet, plenty of the same whole foods and far less sugar and refined starch, already captures most of the benefit the research can vouch for. Keto is a reasonable stricter option, not a prerequisite.

When diet is not the whole answer

Acne has several drivers, and food is only one of them. Hormonal acne, the kind that clusters along the jaw and flares with the menstrual cycle, is heavily influenced by conditions such as polycystic ovary syndrome, where insulin resistance is central; for that overlap our article on keto and PCOS is the better starting point. Genetics, stress, skincare products and bacteria all play their part too. Diet can be a real lever, and for some people a surprisingly effective one, but it is not a cure and it is no substitute for proper treatment. Persistent, painful or scarring acne deserves a dermatologist, and there is no shame in using medical options alongside a sensible diet rather than instead of one.

The bottom line

A randomised trial found that low-glycaemic eating roughly doubled the improvement in acne over twelve weeks, and the biology of insulin and IGF-1 explains why steadier blood sugar calms the skin. Keto sits at the strict end of that same low-glycaemic scale, so it is a reasonable bet for clearer skin, with two honest caveats: keto-specific trials are still limited, and dairy is the variable most likely to hold your results back. Give any change a couple of months, watch your own response rather than the calendar, and keep the dermatologist’s door open for anything stubborn.

This is general information about the ketogenic diet, not medical advice. Acne can need medical treatment; see a doctor or dermatologist for persistent or severe acne. If you are pregnant, on medication, or managing a condition such as diabetes, speak to a doctor or dietitian first.

Source: Smith RN, et al. A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial. American Journal of Clinical Nutrition. 2007;86(1):107-115. Read it here. See also the 2024 review on diets and inflammatory skin conditions here.