The validated 4-step protocol
Step 1: Gentle BHA cleanser (0.5–1% salicylic acid). Step 2: Niacinamide 4–5% serum. Step 3: Lightweight oil-free moisturiser. Step 4: SPF 50+ (AM) or retinoid 0.025% (PM). That is it. Adding more products increases the risk of irritation, product interaction, and adherence failure.