Exfoliate gently 2–3 times per week with a mild chemical exfoliant such as lactic acid, glycolic acid, or salicylic acid
Moisturize daily with urea, lactic acid, ceramides, or glycerin
Apply sunscreen to exposed knees every day
Reduce friction from kneeling, tight clothing, and rough surfaces
Use a gentle cleanser and avoid harsh scrubbing
Try brightening ingredients such as niacinamide, vitamin C, azelaic acid, or kojic acid
Use retinoids at night if tolerated
Keep the area well hydrated and avoid picking or scratching
Maintain a healthy weight if excess friction or pressure is contributing
Treat underlying causes such as eczema, insulin resistance, or hormonal issues
See a dermatologist if the darkness is sudden, severe, thickened, itchy, or not improving
Consider professional treatments such as chemical peels, laser therapy, or prescription creams under medical guidance