This article is a part of CNN Underscored’s Guide to Age-Defying Beauty, a weeklong focus on the essential products, tips and tricks to enhance your glow at any age. We’ll be featuring editor-tested ...

If you're keen to book in for an LED facial or invest in a techy, at-home device but aren't sure how or even if it can benefit your skin, learning how light therapy works and what it actually is to ...