These products also boost collagen. Tretinoin was the first retinoid approved by the U.S. Food and Drug Administration, but ...

She says, "You should not be applying tretinoin like this directly on your scalp," adding what harmful effects this may have, "It is only going to give you more irritation or post-inflammatory ...

If there's one skincare ingredient that is constantly raved about by dermatologists, it's retinol - and more specifically, ...