Acne isn't "dirty skin" and it isn't "food sin". It's a medical issue with clear causes. Here are the ingredients that actually convince in studies — and which ones are just marketing.
For severe acne (cystic, scarring, large-area, painful), the rule is: see a dermatologist. There are prescription treatments (isotretinoin, antibiotic creams, spironolactone) that are significantly more powerful than anything in the drugstore. Over-the-counter products are great for mild to moderate acne — but not a substitute for medical treatment in severe cases.
A fat-soluble acid that penetrates pores and cleans them from inside. Especially good for blackheads (comedones) and blemished skin. Usual concentration: 0.5–2 %. Found in toners, cleansers and spot treatments.
When to use? In the evening, 2–3× per week at first. Not together with retinol on the same evening.
The classic against inflammatory pimples. Kills acne bacteria (Cutibacterium acnes). Fast and powerful — but can dry skin out and bleach towels (!). Usual concentration: 2.5 % (gentle, almost as effective as higher doses) or 5 %.
When to use? Spot-apply to inflamed pimples. Don't apply over large areas unless a doctor prescribes it that way.
Vitamin A derivatives that boost cell turnover and prevent comedones. Adapalene (e.g. in Differin Gel) is a medicinal ingredient available through pharmacies. Whether it suits your skin and how to get it is best clarified with a dermatologist or pharmacist.
When to use? In the evening, ease in slowly (start with 2× per week). Sunscreen the next morning is mandatory, because retinoids make skin more sensitive.
The underrated all-rounder. Works against acne, pigment spots and redness. Very well tolerated, also allowed during pregnancy. Usual concentration: 10 % (over-the-counter) to 20 % (prescription).
When to use? 1–2× daily. Combines well with other actives.
Vitamin B3. Regulates sebum production, reduces redness, visibly reduces pores. Very well tolerated. Concentration: 5 %. Can be used both in the morning and evening.
Acts anti-inflammatory from outside (in creams) and also from within (as a dietary supplement, consult a doctor). Particularly helpful with inflammatory acne.
Antibacterial, slightly anti-inflammatory. Studies show effect at 5 % dilution, comparable to benzoyl peroxide — but gentler. Never apply undiluted, always dilute!
Patience. Acne treatments need 6–12 weeks before you see a clear difference. Some actives (especially retinoids) cause a purging effect in the first 4–6 weeks — the skin gets worse briefly before getting better. That's normal.
What's not normal: burning pain, severe redness, swelling. In that case: stop the product and consult a doctor if needed.
This is debated, but research leans towards three factors:
But: diet alone rarely cures acne. It can support — topical treatment with actives remains the main work.