When multiple active ingredients are used, their compatibility matters. Some work well together; others can strain skin when used at once. Care is needed, especially in multi-step routines.
A general principle is not to layer sensitive or strong ingredients at once. For example, combining several exfoliating ingredients in one routine can strain the barrier and cause sensitivity. "Less but right" applies: a few well-chosen, compatible ingredients are more sustainable than many.
Introducing a new active one at a time and observing your skin's response is safest. When unsure which ingredients can be combined, consult a dermatologist for a personalised assessment. EVİA offers protocol support for clinicians.