As cooler temperatures move in and our biological clocks adjust to time changes, the shift in natural light patterns can have an impact on our mental state of mind. The “winter blues” are very real for a lot of people: For some the effects are far greater, leading to severe lows and a medical diagnosis known as seasonal affective disorder (SAD), which is listed under DSM-5 by the American Psychiatric Association. Symptoms of SAD can include tiredness, weight gain, mood swings and sleep issues. But studies have shown that light therapy lamps (also known as SAD lamps) can be effective in helping to reduce symptoms.

Dr. Michael Terman, president of Center for Environmental Therapeutics and professor of Clinical Psychology in Psychiatry at Columbia University has studied the effects of SAD in clinical trials. “Milder cases do not match the severity seen in clinical cases, but are burdensome nonetheless,” he says over an email interview. “‘Winter blues’ are about three times more prevalent than cases of full-blown depression, but they follow the same time course and respond to the same light therapy regimen (10,000 lux in 30-minute sessions shortly after waking).” Dr. Terman recommends placing a lamp that is height-adjustable so the screen faces downward toward the eyes at a desk or kitchen table, but not in the bedroom. In general, the lamps should offer 10,000 lux brightness and be a UV-free, LED light.

For some people, the benefits of using light therapy lamps are long term. Board certified health coach and author, Robyn Youkilis says that people who work at their desks year-round or face constant inclement weather during winter months don’t get enough natural light and can benefit from using these devices at any time of year. She suggests starting slow. “I have found that the lowest lux setting is generally safe for everyone. At first see how your body reacts—you want to feel bright like you would on a sunny day, not overstimulated or too alert,” she says.

If you’re ready to buy a light therapy lamp, we’ve compiled a list of the best options that range from the most affordable to the best for travel. But keep in mind that these recommendations are in no way an endorsement for treating a medical condition. If you think you might be suffering from SAD, please seek medical advice for the best treatment options.