Acne myths: toothpaste, dirty skin, the sun, diet, 'biofilm' and more, fact-checked

Myth: acne is caused by dirty skin

False. The NHS says acne isn’t caused by poor hygiene, because the biological causes happen beneath the skin. Acne starts when hair follicles get blocked by oil and dead skin cells, and is driven by hormones, genetics and inflammation.

Washing more doesn’t help either. The NHS says washing more than twice a day may aggravate the skin, and the AAD recommends washing twice a day plus after sweating.

Myth: blackheads are dirt in your pores

False. The NHS says blackheads aren’t filled with dirt; they’re dark because of pigment produced by the lining of the hair follicle. Many “blackheads” on the nose aren’t even blackheads; see blackheads vs sebaceous filaments.

Myth: scrubbing harder clears acne

False. The AAD says scrubbing irritates skin and can make acne flare. Use a mild cleanser with your fingertips and pat dry.

Myth: put toothpaste on a pimple

False. The NHS says that although toothpaste contains antibacterial ingredients, it can irritate and damage the skin, so it isn’t recommended. Use a thin layer of benzoyl peroxide, salicylic acid or adapalene instead. See pimple patches and spot treatments.

Myth: the sun (or a sunbed) clears acne

False. The NHS says there’s no conclusive evidence that sunbathing or sunbeds improve acne. Some acne medicines make skin more sensitive to light, and sun exposure damages skin and raises skin cancer risk. The AAD adds that sun can darken acne and make it last longer, which is why marks can look worse after a summer.

Skin Realist check: a tan can hide redness for a while, which is probably where this myth comes from. It doesn’t treat the acne, and the marks are often darker when the tan fades.

Myth: diet has nothing to do with acne (or everything)

Both are overstated. The AAD says:

• small studies suggest a low-glycemic diet may reduce acne, though other studies found no link
• all types of cow’s milk (whole, low-fat and skim) have been linked to acne
• no studies have found that yogurt or cheese lead to more breakouts
• more research is needed, and clear skin still needs skin care and acne treatment

The NHS also lists high-glycemic diets as a possible trigger. So diet may be a factor for some people, but cutting out foods is rarely enough on its own. If you suspect a food, the AAD suggests seeing whether avoiding it makes a difference.

Myth: popping a pimple makes it heal faster

False. The AAD says popping at home often pushes material deeper into the skin, increasing inflammation, and can lead to permanent scars, more noticeable acne, more pain and infection. A dermatologist can extract blackheads and whiteheads or inject a painful cyst safely.

Myth: acne is contagious

False. The NHS says you can’t pass acne on to other people.

Myth: sex or masturbation affects acne

False. The NHS says having sex or masturbating doesn’t make acne better or worse.

Myth: only teenagers get acne

False. The AAD says some adults keep getting acne into their 30s, 40s and 50s, and some get it for the first time as adults; women are more often affected. The NHS says about 3% of adults over 35 have acne. See hormonal and jawline acne.

Myth: people with acne shouldn’t wear makeup or moisturiser

False. The AAD says people with acne can wear makeup if they choose non-comedogenic products and remove them every night. And the AAD says dry, irritated skin can lead to more acne, recommending a moisturiser for acne-prone skin twice a day. See makeup for acne-prone skin.

Myth: more product (or a higher percentage) works faster

False. The AAD says applying more medication than recommended doesn’t clear acne faster, and the AAD lists switching treatments every week or so as a habit that irritates skin. Higher strengths mostly add irritation. See OTC acne treatments compared.

Myth: retinoid “purging” means it’s working

Partly true, often misused. The adapalene Drug Facts label says acne may seem to worsen in the early weeks before it improves. But a 2009 review in the Journal of Drugs in Dermatology concluded it’s unlikely that starting a topical retinoid causes acne to flare, and attributed early worsening to acne’s natural course. Either way, getting worse beyond 6 to 8 weeks, or bumps in new places, isn’t purging. See closed comedones.

Myth: “biofilm” is the hidden cause of your acne

Overstated. Some brand blogs claim acne is really caused by bacterial biofilms, protective layers bacteria build inside follicles, and sell products to “break them up”. This comes from a genuine research theory: papers such as PMID 23392942 and PMID 19671069 describe how Cutibacterium acnes biofilms and the immune response might contribute to acne.

But a theory about mechanism isn’t proof that a “biofilm” product works. We found no clinical trials showing products marketed against biofilm clear acne better than standard treatments. The treatments with strong evidence are still benzoyl peroxide, retinoids and, for some people, prescription options.

Myth: acne will go away on its own, so it isn’t worth treating

Risky. The NHS says many people’s acne improves with age, but the AAD says deep nodules and cysts often cause permanent scars, and the sooner you treat them, the fewer scars you’ll have. Acne can also affect mood and confidence. Effective treatment exists; see when to see a dermatologist.