Acne care products are a mix of four categories: cosmetics, quasi-drugs, over-the-counter medicines and prescription medicines. Each category allows different ingredients at different concentrations, and the gap in both effect and side effects is wide. This guide draws on Korea's Ministry of Food and Drug Safety (MFDS) rules, namely the "Regulation on Safety Standards for Cosmetics" and the "Rules on the Safety of Drugs and Related Products," along with the American Academy of Dermatology (AAD) guidelines.
The four categories — what sets them apart
| Category | Key ingredients / concentration | How to buy |
|---|---|---|
| Cosmetics | Salicylic acid 0.5–2%, niacinamide, tea tree | Regular stores and online |
| Quasi-drugs | Salicylic acid up to 6%, some soaps and cleansers | Regular stores (MFDS certification required) |
| OTC medicines | Benzoyl peroxide (BPO) 2.5–10%, some azelaic acid | Pharmacy (a pharmacist may recommend) |
| Prescription medicines | Retinoids (tretinoin, adapalene 0.1%+), antibiotics, isotretinoin | Dermatology prescription (a doctor's visit is required) |
The key point: cosmetics can help ease acne-prone skin, but treating acne is the domain of medicine. Moderate to severe acne does not clear with cosmetics alone, and a dermatologist visit is recommended.
How acne forms in four stages
- Excess oil production: androgens stimulate the sebaceous glands.
- Dead skin clogs the follicle opening: when cell turnover goes off-balance, the follicle blocks up and whiteheads and blackheads appear.
- C. acnes multiplies: this anaerobic bacterium grows inside the trapped oil.
- Inflammation: immune cells react to the bacteria, leading to red papules, pus and cysts.
Each ingredient acts on one or more of these four stages.
Cosmetic ingredients — MFDS usage limits
Salicylic acid (BHA)
- MFDS limit: 0.5–2% in regular cosmetics, and up to 6% in quasi-drugs such as acne soaps.
- How it works: it clears clogged dead skin inside the follicle and has a mild anti-inflammatory effect.
- Clinical reports: several trials report a statistically significant improvement over placebo in mild to moderate acne.
- Cautions: avoid high concentrations during pregnancy, and note that it raises sun sensitivity.
Niacinamide
- Typical use: used at 2–10%.
- How it works: it helps calm inflammation and regulate oil, and it eases the pigmentation that lingers after a breakout.
- Clinical reports: at 4%, it showed an effect similar to 1% topical clindamycin (Shalita AR et al., Int J Dermatol 1995; 82% vs 68% improvement after eight weeks).
- Cautions: it is very low in irritation, so it suits sensitive skin too.
Tea tree oil
- Typical use: a 5% topical concentration is recommended.
- How it works: it has antibacterial action against C. acnes and other microbes, along with an anti-inflammatory effect.
- Clinical reports: 5% tea tree matched 5% BPO with less irritation, though it worked somewhat more slowly (Bassett IB et al., Med J Aust 1990).
- Cautions: it can trigger allergy, so a patch test is recommended.
Azelaic acid
- Cosmetic concentration: usually 5–10%.
- Prescription concentration: as a medicine it goes up to 15–20%.
- How it works: it combines antibacterial action with normalised cell turnover, anti-inflammatory effects and lighter pigmentation.
- Notable point: it is considered relatively safe during pregnancy and breastfeeding (FDA Pregnancy Category B).
OTC medicines — available at the pharmacy
Benzoyl peroxide (BPO)
- Concentration: Korean OTC products come in 2.5%, 5% and 10%.
- How it works: it kills C. acnes through oxidation and calms inflammation.
- Guideline recommendation: it is a first-line OTC ingredient for mild to moderate acne (AAD Acne Guidelines, Zaenglein AL et al., J Am Acad Dermatol 2016).
- Cautions: early on it can bring dryness, redness and peeling. The standard advice is to start at 2.5% and build up slowly, and note that it can bleach clothing and towels.
Using BPO and a retinoid at the same time of day can let the BPO oxidise the retinoid and weaken it. It is better to split them, with BPO in the morning and the retinoid at night, or to alternate days.
Prescription medicines — from a dermatologist
Topical retinoids
- Tretinoin: used at 0.025–0.1%.
- Adapalene: comes in 0.1% and 0.3%.
- Tazarotene: used at 0.05–0.1%.
- How it works: it normalises cell turnover and prevents follicles from clogging.
- Cautions: absolutely contraindicated in pregnancy, with high sun sensitivity and strong irritation early on.
Topical and oral antibiotics
- Topical: clindamycin and erythromycin, generally used alongside BPO.
- Oral: doxycycline and minocycline are used for moderate to severe inflammatory acne.
- Cautions: because of antibiotic resistance, long-term use on their own is not recommended.
Isotretinoin (oral)
- It is the standard treatment for severe nodular and cystic acne.
- Among acne medicines it acts very strongly and carries heavier side effects, and it is absolutely contraindicated in pregnancy. It is strongly teratogenic on the reported evidence.
- It must only be taken under a dermatologist's prescription and regular monitoring.
Recommendations by acne stage — AAD guidelines
| Stage | Features | First-line recommendation |
|---|---|---|
| Mild | Mostly whiteheads and blackheads, little inflammation | Cosmetic BHA + topical retinoid, or OTC BPO |
| Moderate | Many papules and pustules, some nodules | Topical retinoid + BPO + topical/oral antibiotic |
| Severe | Nodules and cysts, risk of scarring | Oral isotretinoin (dermatology prescription) |
