Yes. Teeth whitening lights have been proven to speed up the whitening process by accelerating the chemical reactions occurring as the bleaching gel makes contact with the teeth. In most cases, LED (light-emitting diode) light is used to activate the agent.
However, by no means do whitening lights make teeth whiter on their own. It’s simply a technology that plays a role in the bleaching process but it won’t work unless the teeth have been smeared with hydrogen peroxide or another whitening product.
In most cases, the LED light activator will not cause any side effects. What creates problems with the oral tissues is the bleaching chemical itself. If you have any concerns about that, talk to your dentist.