CBD is one of dozens of cannabinoids (which are natural compounds) found in cannabis plants. CBD used in beauty products is from hemp (not marijuana), and it is not psychoactive like the cannabinoid THC is. (That is, CBD cannot get anyone high, no matter how much is used.)
Studies have shown that CBD (and other cannabinoid compounds) can interact with the body's own endocannabinoid system, which may help to ease pain, anxiety and other ailments. While the role of hemp oil (and specifically CBD) is less studied in skin care, hemp oil has been used by people for thousands of years, and is known to be rich in essential fatty acids and phytonutrients. Its use as an ingredient in beauty products is relatively new...and so far, users have glowing reviews.