Hi Alice, I was wondering is it true that tretinoin can break down under artificial light such as from lamps/light bulbs and from devices such as tv? Many thanks

Hi, yes, it’s true that tretinoin can break down under artificial light – though it depends on the formulation, the strength of the light source and how long the product is exposed to the light. The same thing happens with retinol. It’s a key reason why skincare professionals always suggest using any retinoid/ vitamin A-based product at night, and a good reason for putting it on shortly before bedtime rather than earlier in the evening.