Can I use acids and retinol on the same night?

It is generally not recommended to use AHA/BHA acids and retinol on the same night, especially for beginners, as the combination can cause significant irritation, redness, and barrier damage. Each ingredient increases cell turnover and used together they amplify irritation. Skin cycling addresses this by separating exfoliation night and retinol night. Advanced users with tolerant skin may use them on alternate nights but rarely the same night.