Most popular acne advice falls into one of three groups: true (stress, friction and picking really do matter), partly true (diet may play a role for some people, but the evidence is mixed), and false (acne isn’t caused by dirty skin, and toothpaste isn’t a treatment). Below, we go through 12 common claims and grade each one by the strength of the evidence, drawing on the American Academy of Dermatology’s acne guidelines (2016 and 2024) and the key studies behind each question.
How we grade the evidence
These grades are our editorial summary of the research, not an official scale:
- Strong: consistent results from good-quality randomized trials or systematic reviews, or broad agreement in clinical guidelines.
- Moderate: some trials or consistent observational studies, with limitations.
- Limited: small, short, older or conflicting studies. The answer isn’t settled.
- None: no meaningful research supports the claim, or the evidence points the other way.
The claims at a glance
| Claim | Verdict | Evidence level |
|---|---|---|
| Acne is caused by dirty skin | False | Strong (against the claim) |
| Washing more often clears acne | False beyond twice a day | Limited (one small trial) |
| High-glycemic diets worsen acne | Possibly, for some people | Limited to moderate |
| Dairy causes acne | Unproven; association only | Limited (observational) |
| Chocolate causes acne | Unclear | Limited and conflicting |
| Toothpaste dries out pimples | False; it can irritate | None supporting it |
| Sun or tanning clears acne | False | None supporting it |
| Stress makes acne worse | True for existing acne | Limited to moderate |
| Popping pimples helps them heal | False | Clinical consensus against it |
| Makeup always causes acne | False; product choice matters | Clinical consensus |
| Acne is contagious | False | Strong (against the claim) |
| You just have to grow out of it | False | Strong (effective treatments exist) |
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Myth: acne is caused by dirty skin
Verdict: false. Evidence: strong.
Acne starts inside the hair follicle, below the surface. Oil and dead skin cells form a plug, C. acnes bacteria multiply, and inflammation follows. That’s the process described by the NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases and the AAD. The dark tip of a blackhead isn’t dirt; it’s trapped material that darkens on contact with air.
The flip side matters too. The AAD warns that scrubbing and over-washing irritate skin and can make acne look worse.
Myth: washing more often clears acne
Verdict: false beyond twice a day. Evidence: limited.
In a small 2006 randomized trial, people who washed their face twice a day saw modest improvement, while washing once a day was associated with worsening. Washing four times a day didn’t add benefit over twice. That matches AAD advice: wash twice a day and after sweating with a gentle cleanser and your fingertips.
Partly true: high-glycemic diets may worsen acne
Verdict: possibly, for some people. Evidence: limited to moderate.
A diet’s glycemic load reflects how much it raises blood sugar. High-glycemic foods include white bread, sugary drinks and many processed snacks. The theory is that frequent blood-sugar spikes raise insulin and insulin-like growth factor 1 (IGF-1), which may increase oil production and androgen activity.
- A 2007 randomized trial in Australian young men found a low-glycemic-load diet over 12 weeks reduced acne lesions more than a conventional diet. However, participants on the low-glycemic diet also lost weight, which complicates interpretation.
- A 2012 randomized trial in Korean patients found a low-glycemic-load diet over 10 weeks improved acne and reduced the size of oil glands on skin biopsies.
These are small trials, and the weight loss in the first one makes it hard to credit the diet alone. The AAD’s 2016 acne guidelines called the evidence on high-glycemic diets emerging and recommended no specific dietary changes. A lower-glycemic eating pattern is reasonable for general health, and it may help some people’s skin. But it shouldn’t replace proven treatment.
Partly true: dairy and acne
Verdict: unproven; association only. Evidence: limited (observational).
Several large observational studies have linked milk intake, especially skim milk, with acne in teens and young adults. A 2018 meta-analysis of studies including about 78,500 children, adolescents and young adults found higher odds of acne with higher dairy intake, particularly milk. A 2019 meta-analysis of observational studies reached similar conclusions for milk, with less consistent findings for other dairy foods. Proposed explanations include hormones and growth factors in milk, and milk’s effect on insulin and IGF-1.
But observational studies can’t prove cause and effect. People who drink more milk may differ in other ways, and diet recall is imprecise. There are no good-quality trials showing that cutting dairy improves acne. The AAD’s 2016 acne guidelines noted that dairy, especially skim milk, may influence acne, but recommended no specific dietary changes.
Practical take: if you notice a clear, repeatable pattern between dairy and breakouts, a trial of cutting back, planned with a clinician or dietitian so you still get enough calcium and vitamin D, is reasonable. It’s not necessary for most people.
Whey protein supplements
Case reports and small case series have described acne starting or worsening after people began whey protein supplements, often in bodybuilders. This is weak evidence, but if your acne appeared after starting a supplement, mention it to your clinician.
Unclear: chocolate and acne
Verdict: unclear. Evidence: limited and conflicting.
The famous 1969 study in JAMA that “cleared” chocolate compared chocolate bars with a similar sugary, fatty placebo bar and found no difference. Critics have pointed out the study’s short duration and that the placebo bar was itself high in sugar and fat, so it couldn’t show whether those ingredients matter. Later, small trials pointed the other way:
- A 2014 double-blind trial in a small group of men with acne-prone skin found that capsules of 100% cocoa increased acne lesions compared with placebo.
- A 2016 randomized crossover study in college students found more acne lesions after eating milk chocolate than after eating jelly beans with similar calories.
These studies are small, short and difficult to blind, so they can’t settle the question, and they don’t show that avoiding chocolate treats acne. If you notice a clear pattern, cutting back won’t hurt, but don’t expect it to replace real treatment.
Myth: toothpaste dries out pimples
Verdict: false; it can irritate. Evidence: none supporting it.
There’s no clinical evidence that toothpaste treats pimples. Toothpaste is formulated for teeth, and ingredients such as detergents, flavorings (like menthol), whitening agents and baking soda can irritate or burn facial skin. That can leave a spot redder and more noticeable, or cause a rash. The same goes for lemon juice, rubbing alcohol, garlic and undiluted essential oils.
A better option for a single spot is an over-the-counter benzoyl peroxide or salicylic acid spot treatment, or a hydrocolloid patch to stop you picking. See our guide to pimple patches.
Myth: sun or tanning clears acne
Verdict: false. Evidence: none supporting it.
A tan can temporarily mask redness, which may be why this myth persists. But sun exposure doesn’t treat acne, and it damages skin, raising skin cancer risk. It also causes problems for people with acne specifically:
- Many acne treatments, including retinoids such as adapalene and tretinoin, can make skin more likely to burn. The Differin label advises limiting sun exposure and using sunscreen.
- UV exposure can darken the marks acne leaves behind, making them last longer.
Use a broad-spectrum, non-comedogenic sunscreen daily; our guide to sunscreen for acne-prone skin explains how to choose one. (Medical light and laser therapies used by dermatologists are different, controlled treatments, not the same as sunbathing.)
True: stress can make acne worse
Verdict: true for existing acne. Evidence: limited to moderate.
Stress doesn’t cause acne on its own, but it’s linked to flares. A 2003 study of university students found acne got worse during exams, and the worsening was associated with higher self-reported stress. The AAD lists stress among the factors that can worsen acne. Stress management won’t replace treatment, but it’s worth factoring in, especially because acne itself can cause stress.
Myth: popping pimples helps them heal
Verdict: false. Evidence: clinical consensus against it.
The AAD advises against popping, squeezing or picking. Doing so can push material deeper into the skin, increase inflammation, and raise the risk of dark marks, infection and scars. For a large, painful spot, a dermatologist can treat it safely, for example with a corticosteroid injection or drainage. See our guide to acne scars for why prevention matters.
Myth: all makeup causes acne
Verdict: false; product choice matters. Evidence: clinical consensus.
You don’t need to stop wearing makeup. The AAD recommends choosing products labeled “non-comedogenic” or “won’t clog pores” and removing makeup before bed. Heavy, oily products can contribute for some people, as can hair oils and pomades near the hairline. If you suspect a product, stop it and reintroduce products one at a time.
Myth: acne is contagious
Verdict: false. Evidence: strong.
You can’t catch acne from someone else. The bacteria involved live on nearly everyone’s skin; acne depends on your follicles, oil production, hormones and genetics. (Sharing towels or makeup isn’t a great idea for general hygiene reasons, but it won’t give you acne.)
Myth: you just have to wait to grow out of it
Verdict: false. Evidence: strong.
Acne often improves after the teen years, but it can persist or start in adulthood, especially in women (see hormonal acne in adult women). More importantly, effective treatments exist, and the AAD recommends treating acne early to reduce the risk of scars and emotional distress. Waiting it out means risking marks that last far longer than the acne.
What actually works
The strongest evidence is for proven treatments, not lifestyle changes:
- Benzoyl peroxide and topical retinoids (strong recommendations in the 2024 AAD guidelines);
- prescription options, including topical antibiotics used with benzoyl peroxide, oral doxycycline, hormonal therapy and isotretinoin for severe acne;
- a simple, gentle routine that you can keep up for months.
Our step-by-step guide to getting rid of acne and our acne skincare routine put this into practice. For the basics of what acne is, see what is acne?
When to see a dermatologist
See a dermatologist or your doctor if you have deep, painful spots, scarring or dark marks, if about three months of consistent over-the-counter treatment hasn’t helped, if acne affects your mood, or if you’re pregnant, breastfeeding or under 18 and want to start treatment.