Retinol skincare products suddenly seem to be everywhere, promising clear, radiant and “youthful” skin.But what’s the science ...

Retinol, on the other hand, is more tricky. “There's a lot more limitation in terms of what you should be using in the same routine as retinol, just because it's irritating in itself,” she says.

She explains that she uses retinol at night to help with both acne and skin rejuvenation. As for glycolic acid, she prefers it in cleansers and chemical peels for a periodic skin brightening effect.

When used appropriately, glycolic acid will peel or exfoliate away the outer layer of dead skin, explains Dr. Koo. Used periodically in conjunction with retinol (at separate times of the day or on ...

Most dermatologists estimate that retinol is roughly 10 times less potent than tretinoin, meaning that when retinol undergoes the conversion process, only about 10 percent of it becomes retinoic ...