Collection: Cos De BAHA

Cos De BAHA is a Korean brand specialising in high-percentage, single-active serums — typically containing one or two clinical-strength actives per bottle rather than complex multi-ingredient formulas. Each product is named directly after the percentage and active it contains (Niacinamide 20%, Retinol 2.5%, Azelaic Acid 10%), making it easy to build a transparent, results-focused routine. The brand sits between drugstore minimalism and prescription-grade strength, offering dermatology-style actives without the prescription markup.

Not for most users. Niacinamide is one of the most well-tolerated skincare actives — clinical studies show even 10% and 20% concentrations are safe for daily use on healthy skin. The Cos De BAHA Niacinamide 20% + Zinc PCA 4% Serum is designed to address oily, congested, breakout-prone and uneven-toned skin in one product. For very sensitive or barrier-compromised skin, start every other day and build up to twice daily. If skin gets red or stings, switch to a lower percentage (5–10%) until tolerance builds.

2.5% is a higher-strength over-the-counter retinol — most beginner retinol products contain 0.1–0.5%. Cos De BAHA Retinol 2.5 is intended for users who have already built tolerance to lower-percentage retinol and want stronger results on fine lines, texture and pigmentation. Start by using it 1–2 evenings per week, applied to dry skin, and follow with a hydrating cream like AESTURA Atobarrier 365 to buffer dryness. Always pair with daily SPF50+ since retinol increases UV sensitivity. Not recommended during pregnancy or breastfeeding.

Azelaic acid is a naturally-occurring dicarboxylic acid with multiple skin benefits: it kills acne-causing bacteria (P. acnes), reduces inflammation in rosacea and redness-prone skin, fades post-inflammatory hyperpigmentation, and gently unclogs pores. At 10%, the Cos De BAHA serum delivers near-prescription-strength results on acne, redness, melasma and uneven tone — all in one product. Apply once or twice daily on clean skin; results visible in 4–8 weeks. Pregnancy-safe (unlike retinol), making it a strong choice for expectant mothers.

Yes — but rotate strategically rather than layering everything at once. A common rotation: Vitamin C in the morning, Niacinamide 20% as the daytime treatment under SPF, Retinol 2.5 (or Azelaic Acid for sensitive skin) in the evening, Tranexamic Acid added 2–3 evenings per week for pigmentation. Avoid stacking retinol + AHA + vitamin C on the same evening — alternate them across the week. Always wait 1–2 minutes between layers and apply a hydrating cream as the final step to buffer irritation.