Acne and Dietary Supplements: What Really Works According to Trials

Yes, to a documented extent. A systematic review published in JAMA Dermatology evaluated 42 randomized trials totaling 3,346 participants. Studies of fair to good quality show potential benefit for zinc, vitamins B5 and D, green tea extract, probiotics, and omega-3s, most often measured by a reduction in the number of lesions or an improvement in overall assessment. The authors note that many studies are small in size and that larger trials remain necessary. The message is a possible supporting role, not a replacement treatment.

No. The JAMA review speaks of a possible and supporting role. Moderate to severe acne, with nodules, cysts, or risk of scarring, requires a dermatologist and treatments whose efficacy is established at a completely different level of evidence. Supplements have their place in mild acne, as an accompaniment to treatment, or to correct underlying factors, never instead of a consultation when the skin is affected.

Trials on probiotics and omega-3s lasted 12 weeks, and this is a realistic benchmark: the renewal cycle of an acne lesion and that of the epidermis are measured in weeks. Nothing should be judged before six weeks, and three months is the honest timeframe. A photo at the start, in the same lighting, helps to see progressive improvement that daily mirror checking obscures.

Zinc. A meta-analysis published in Dermatologic Therapy demonstrated two things: people with acne have significantly lower blood zinc levels than controls, and those treated with zinc achieve a significant reduction in the number of inflammatory papules compared to those not treated, both as monotherapy and as a supplement to treatment. The adverse effect profile was not different from that of comparators, except for digestive discomfort.

Clinical trials generally used doses higher than reference nutritional intakes, in a therapeutic approach. A supplement providing 14 mg of zinc per day, approximately 140% of reference values, falls within a nutritional approach: it corrects the relative deficit demonstrated in people with acne, without reaching the doses used in trials. High doses require medical advice, as long-term zinc can interfere with copper absorption. Gluconate is the form most commonly used in studies.

The JAMA review describes them as rare for most interventions, with one exception: digestive effects reported for zinc, nausea and gastric discomfort, which are limited when capsules are taken with meals. At high and prolonged doses, zinc can also interfere with copper absorption, which is a reason not to exceed recommended doses without medical advice.

A randomized, double-blind, placebo-controlled trial published in 2024 followed 74 patients aged 12 to 30 years for 12 weeks. The product combined Lactobacillus rhamnosus and spirulina. An improvement in the global severity scale was observed in 50% of patients on probiotics versus 29% on placebo, and the number of non-inflammatory lesions decreased significantly more. Tolerability was identical in both groups. The JAMA review classifies probiotics among interventions with potential benefit.

A randomized 12-week trial in untreated acne patients showed that omega-3s increase intestinal microbiota diversity, enrich butyrate-producing bacteria, and improve the GAGS severity score. The proposed mechanism operates through the gut: omega-3s modify the flora, which modifies skin inflammation. The JAMA review also classifies them among interventions with potential benefit. A dietary literature review furthermore identifies fatty acids among protective factors.

Because two independent findings converge: oral probiotics and oral omega-3s improve acne by modifying intestinal flora, even though they do not act directly on the skin. A systematic review of the skin microbiome recalls on its side that acne involves an imbalance between Cutibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis on the skin surface. The hypothesis is that inflammation of intestinal origin alters the skin terrain. It's a solid lead, but not yet an entirely demonstrated mechanism.

The review JAMA Dermatology ranks it among interventions with potential benefit in studies of fair to good quality. The reasoning is based on correcting a deficiency: vitamin D plays a role in immune regulation and keratinocyte differentiation, and deficiency is common. It's not an acne treatment per se, but a terrain factor worth verifying through testing, especially in winter.

These are the two most surprising findings from the JAMA review, and the authors report them alongside the others. Vitamin B5, pantothenic acid, plays a role in lipid metabolism, including sebum. Green tea extract owes its interest to EGCG, a catechin with anti-inflammatory properties and sebum production-modulating effects. Sample sizes remain modest, and these two leads should be considered as signals to be confirmed rather than established facts.

Not sugar itself, but glycemic load. A systematic review of 34 studies concludes that a high glycemic index and high daily glycemic load are positively associated with the onset and severity of acne, an observation supported by randomized controlled trials. The effect is described as modest but significant. The mechanism works through insulin and IGF-1, which stimulate sebum production and proliferation of follicle cells.

A meta-analysis of observational studies finds an association between milk consumption and acne: odds ratio of 1.48 for total milk, 1.25 for low-fat milk, and 1.82 for skim milk, with the category consuming the most dairy products having an odds ratio of 2.61. The interesting point is that neither yogurt nor cheese were associated with risk. A more recent review qualifies this by noting that the link depends on sex, ethnicity, and dietary habits. These are associations, not proof of causality.

A literature review from 2009 to 2020 ranks chocolate among factors favoring acne, alongside high glycemic index foods, dairy products, and fatty foods. But it also specifies that the role of specific components remains unresolved: cocoa, dark chocolate, or milk chocolate are not equivalent, and the respective contributions of sugar and milk versus cocoa in the observed effect cannot be separated. Dark chocolate with high cocoa content is the least affected by this reasoning.

That six families have adequate data according to the reference review: zinc, probiotics, omega-3, vitamin D, B5, and green tea, with zinc leading the way with its own meta-analysis. That diet matters, through glycemic load and milk, but not yogurt or cheese. That effects should be judged at three months. And that acne that leaves marks or persists should be seen by a dermatologist, with supplements playing a supporting role.