This clinician-recommended serum combines pure retinol with niacinamide (Vitamin B3), offering powerful renewal for mature skin. Retinol works by promoting skin cell turnover and boosting collagen production, while niacinamide helps reduce irritation and strengthen the skin barrier. For best results, apply at night (start 2×/week), build usage gradually, and always follow with a broad-spectrum SPF in the morning. Texture improves over time; moisture and tolerance are key.