Condition: Acne

The 2024 American Academy of Dermatology guideline makes a strong recommendation for topical retinoids (adapalene, tretinoin, tazarotene). In a network meta-analysis of 179 randomized trials, a topical retinoid combined with benzoyl peroxide reduced total lesions by about 26% more than placebo in mild-to-moderate acne (mean difference 26.16%, 95% credible interval 16.75 to 35.36). Measured in: Adults and adolescents with acne across the trials underpinning a GRADE-based guideline and a network meta-analysis. Retinoids irritate and can dry or redden the skin in the first weeks, and they were less well tolerated than placebo in the trials. Starting every other night and using a moisturizer is how most people get past that.

A Cochrane review of 120 trials (29,592 participants) found benzoyl peroxide more effective than placebo for participant-rated acne improvement (risk ratio 1.27, 95% CI 1.12 to 1.45) and no meaningful difference from adapalene or clindamycin. Withdrawal for irritation was higher than placebo (RR 2.13, 95% CI 1.55 to 2.93). Measured in: 29,592 participants randomized across 116 trials, mostly mild to moderate acne, mean age 18 to 30. Dryness, redness and burning are common early and are the usual reason people stop. A lower strength (2.5 to 5%) applied once daily at first keeps most people on it. It bleaches fabric, so it marks towels and pillowcases.

The 2024 dermatology guideline strongly recommends oral isotretinoin for acne that is severe, scarring, causing psychological burden, or failing standard oral or topical therapy. It offers the best chance of lasting clearance, and because it is teratogenic it requires specialist supervision and strict pregnancy prevention. Measured in: Moderate-to-severe acne across the guideline evidence base and a comprehensive isotretinoin review. It needs a dermatologist, blood-test monitoring, and rigorous contraception for anyone who could become pregnant. Dryness of the lips and skin is near-universal; serious adverse events are rare and most effects are reversible.

A Cochrane review of randomized trials found combined oral contraceptive pills reduced inflammatory and non-inflammatory facial lesions, severity grades and self-assessed acne compared with placebo in women. The 2024 dermatology guideline gives them a conditional recommendation. Measured in: Women across randomized placebo-controlled and comparative trials in a Cochrane review. It suits women who also want contraception, takes a few cycles to work, and carries the usual pill considerations such as a small clot risk, so the choice is individual and made with a prescriber.

In the SAFA pragmatic randomized trial (342 women analyzed, 50 to 100 mg/day), more of those on spironolactone reported acne improvement than on placebo by week 24 (82% vs 63%, odds ratio 2.72, 95% CI 1.50 to 4.93), and dermatologist-rated treatment success at week 12 was 19% vs 6%. Headaches were slightly more common (20% vs 12%). Measured in: 342 adult women (mean age 29) with persistent facial acne in England and Wales. It is for women, the benefit builds slowly over months, and it is avoided in pregnancy. Mild side effects include headaches and, at higher doses, more frequent urination.

In a Cochrane review, azelaic acid was probably slightly less effective than benzoyl peroxide for self-rated improvement (risk ratio 0.82, 95% CI 0.72 to 0.95) but about equal to the retinoid tretinoin (RR 0.94, 95% CI 0.78 to 1.14). Most trial participants were women. Measured in: Mostly female participants aged 12 to 30 across 49 topical-treatment trials in a Cochrane review. It can cause mild tingling or itching at first, and it works a little less well than benzoyl peroxide, so it is often chosen for sensitive skin, for the marks (post-inflammatory pigmentation), or during pregnancy.

In a 12-week randomized trial of 43 young men, a low-glycemic-load diet cut total acne lesions by 23.5 versus 12.0 on the control diet (P=0.03) and improved insulin sensitivity. The low-glycemic-load group also lost more weight, which the authors could not fully separate from the diet effect. Measured in: 43 male acne patients aged 15 to 25, 12-week parallel dietary intervention. The low-glycemic-load group also lost weight, so part of the benefit may be weight loss, not the food swap itself, and the trial was in young men only.

A meta-analysis of observational studies found higher acne odds with dairy overall (odds ratio 2.61, 95% CI 1.20 to 5.67), total milk (OR 1.48, 95% CI 1.31 to 1.66) and skim milk (OR 1.82, 95% CI 1.34 to 2.47), while yogurt and cheese showed no association. Measured in: Pooled observational studies (case-control and cross-sectional) of milk and dairy intake and acne. What could explain it instead: Dietary intake was self-recalled (recall bias), milk consumption tracks with other lifestyle and dietary patterns, and reverse causation is possible if people change their diet because of their acne.. These are observational studies: they show that people who drink more milk have more acne, but that is a link rather than a demonstrated cause, and diet was self-recalled.

A single-blinded randomized trial in men with mild-to-moderate acne compared washing once, twice or four times daily for six weeks. There was no significant difference between the groups overall; washing twice daily improved comedones and non-inflammatory lesions, while washing only once daily worsened redness, papules and inflammatory lesions. Measured in: Men with mild-to-moderate acne, randomized to once, twice or four-times-daily washing for six weeks. The trial was small and in men only, and it tested washing frequency, not harsh scrubbing directly, so the practical read is gentle cleansing twice a day, not more.

Nodular and cystic acne can leave permanent scars, and guidelines recommend early, effective treatment (including isotretinoin) for acne that is severe, scarring or psychologically burdensome, because scars are far harder to treat than active acne and become less avoidable the longer severe acne runs. Measured in: Severe and scarring acne across the guideline evidence base and an isotretinoin review. Not all acne scars, and mild acne rarely does. The case for moving quickly applies to the deep, painful, nodular kind and to anyone already seeing marks form.

Clascoterone (brand name Winlevi) inhibits the androgen receptor locally in the oil gland and follicle, the same hormonal driver that oral spironolactone and the combined pill act on, applied to the skin. Because it acts locally it is approved for both males and nonpregnant females, while spironolactone is used only in women. Long-term data and head-to-head trials against the established topicals are still limited.

Systematic reviews of diet and acne find the most consistent signals are high glycemic load and dairy; reviews also list fatty food and chocolate as possible contributors, with the chocolate-specific evidence still unresolved. One small trial (25 acne-prone men eating 25 g of 99% dark chocolate daily for four weeks) reported worse acne scores, but the evidence on chocolate specifically remains limited and inconsistent. Measured in: Systematic review of diet-and-acne evidence 2009 to 2020, plus one small controlled chocolate trial in men. This is about the received wisdom, not any single food. Someone who notices their own skin reacts to a specific food can act on that. The diet signals that hold up are glycemic load and milk, so cutting out chocolate addresses the wrong factor.

A systematic review and meta-analysis found people with acne have significantly lower serum zinc than controls, and zinc treatment (oral or topical) reduced mean inflammatory papule counts compared with no zinc, whether used as monotherapy or an add-on, with no increase in side effects overall. Measured in: Acne patients and controls across the trials pooled in a PRISMA systematic review and meta-analysis. The trials are small and varied in the zinc form and dose. Oral zinc at higher doses can upset the stomach and, taken long term, interfere with copper absorption.

In a 10-week randomized controlled trial of 45 people with mild-to-moderate acne, both omega-3 (2,000 mg of EPA and DHA) and gamma-linolenic acid significantly reduced inflammatory and non-inflammatory lesions, with reduced inflammation and lower interleukin-8 staining on skin biopsy. Measured in: 45 participants with mild-to-moderate acne, 10-week randomized dietary intervention in Korea. One small trial is not enough to call this established. Omega-3 is a low-risk add-on, not a proven acne treatment.

Acne arises from four linked factors in the oil gland and follicle: excess and altered sebum, sticky over-keratinization blocking the pore, the skin organism Cutibacterium acnes, and inflammation. Androgens, insulin and insulin-like growth factor-1 are the main hormonal drivers. This is the well-established mechanism, and it explains why effective treatments target oil, the clog, the bacterium, and inflammation. Surface cleanliness is not part of the chain, so cleaning harder changes little.

In women, acne together with irregular periods, excess facial or body hair, or scalp hair thinning can signal polycystic ovary syndrome or another cause of high androgens, which the international evidence-based guideline treats as a reason for evaluation. A sudden, severe onset with a deepening voice or rapid virilization needs prompt work-up for a more serious androgen source. Measured in: Adolescent and adult women, per an international evidence-based PCOS guideline. Most acne does not mean a hormone disorder. This is about the specific combination of acne with other androgen signs, not acne by itself.