[ZKLabs]

Retinols actually make the skin more resilient to sun damage. They boost collagen and thwart photoaging. A trial retinoic acid user may have turned red as a lobster and got a sunburn. The former will happen because it is a side effect. The latter will happen because it’s what happens with the sun. Hence the early concern. The main reason retinol is used at night is that light deactivates it.