These light boxes simulate sunlight and are generally safe and easy to use. When used properly, the risks are minimal, because of a diffusing screen that filters out the majority of harmful UV rays (unlike tanning beds, which are NOT a good replacement for light therapy). Because of that, the chance of it upping your risk of skin cancer is minimal, but it can never hurt to use sunscreen as an extra precaution, says Rohan.
When buying a light therapy lamp, make sure it's one specifically for SAD, says Winch, since some are for skin conditions or other issues. Each light box will come with its own set of instructions, but typically, you'll be instructed to use it for 15–20 minutes in the morning, a foot or two away from you, and pointed toward your face. Be sure not to look directly into the light, and if you feel jumpy or restless, Winch suggests dialing it back by a few minutes. That said, Rohan strongly recommends seeing a professional first to figure out the right dose and avoid any side effects.