If you’re reading this from a beach in Thailand or from a spa in Tulum, then you can head back out into the sunshine (and send us a postcard, please!). If you’re in the Northern Hemisphere, however, the days are short and dark and most of us feel the effects of seasonal depression and decreased immunity in one way or another. This effect can range from “I’m not in the mood to go out tonight” to full-blown depression.

Light therapy is helpful for people who suffer from seasonal affective disorder (appropriately acronymed SAD), also known as the winter blues. It can also improve the immune function of people who tend to get sick in winter (i.e. almost everyone!). Symptoms of SAD can include fatigue, wanting to sleep more than usual, craving carbs and sugar, slacking off at work, or losing interested in your favorite activities, combined with higher than usual levels of anxiety, sadness, or fear.

Light therapy involves sitting close to a special “light box” for 30 minutes a day, preferably as soon after waking up as possible. With 10,000 lux, a measure of light intensity, the light is around 20 times brighter than typical indoor lighting. Note that hanging out in the actual sun is the best alternative: a bright sunny day can be 50,000 lux or more.

Luminotherapy is one of the best treatments for seasonal depression out there.

“I consider sunlight to be an essential nutrient, although people who live near the poles or spend months on nuclear submarines usually adapt to its deficiency. I have many patients who need sunlight to improve mood and immunity and I recommend light therapy for them,” says leading functional medicine doctor Leo Galland.

Natural light is, of course, ideal, but unfortunately not an option in the Fall and Winter months in many parts of the world. “Exposure to luminotherapy lamps makes it possible to compensate for this lack of natural light,” says head of French luminotherapy leader Dayvia, Hervé Carbonnel.

“Who says?” you ask? SCIENCE.

It all begins with the activation of light receptors at the bottom of our retinas. “The activation of these receptors regulates our biological clock and promotes the secretion of energizing hormones such as serotonin,” says Carbonnel. He adds: “Exposure to light in the morning also blocks the secretion of melatonin, which is abnormally secreted during the day in people experiencing lack of energy or extreme fatigue, craving sweets, or feeling the winter blues.”

Luminotherapy is one of the best treatments for seasonal depression out there. A recent study even showed that luminotherapy can be just as effective as depression medications, such as Prozac. Symptoms of the “winter blues” can disappear within a week of beginning light therapy, but most health professionals recommend continued exposure every day for at least 3 weeks to see lasting benefits.

And hey jetsetters, light therapy is also an amazing anti-jet lag treatment.

And hey jetsetters, light therapy is also an amazing anti-jet lag treatment. Try luminotherapy exposure at least one week before you fly, especially if you’ll be crossing over three or more time zones. Carbonnel suggests a tailored approach to light therapy depending on where you’re headed in order to, he says “manipulate your biological clock.” His recommendation? “Use the light according to your destination. For example, for a trip to the USA from Europe, use the lamp later and later in the evening, but do the reverse for a trip to Asia”

Does this all still sound too high commitment? “A fascinating study at Harvard university found that you do not actually have to see the light for its antidepressant effect to occur. Absorption of light through the skin seems to be enough,” says Galland. So, you can brush your teeth, read a newspaper, or catch up on work while reaping the benefits of light therapy.

Sound good, sunshines?

Rebecca Leffler is an American journalist, author, and wellness consultant. After a long career in entertainment in Paris, France, she’s traded red carpets for green smoothies and croissants for kale. She loves: the morning, yoga, avocados, fresh air, French air, puns, lemons, coconuts, flower, fancy hotel lobbies and chemical-free tampons. She hates: pineapples, negativity, frowning and being cold. Follow her on Instagram or Twitter for more. Photo credit: Astrid di Crollalanza.