These 6 Ingredients Don't Mix Well With the Sun

Second to SPF of every dermatologist's "must apply" list is retinoids (which include both OTC retinol and prescribed retinoic acid).

"This ingredient works by speeding up the cell turnover process, therefore boosting the production of collagen and elastin," says Jeannel Astarita, aesthetician and founder of Just Ageless. "It is useful to refine pores, reduce hyperpigmentation, fine lines, and wrinkles, and to improve skin texture in general. It also works to clear acne."

The miracle ingredient comes with the downside that it doesn't mix well with the sun, which is why it's recommended for nighttime use. The primary reason why is because the sun essentially breaks it down, rendering it ineffective. Astarita also adds that wearing retinol during the day may cause your skin to be skin more sensitive to the sun given its potent exfoliating properties.

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