Should You Take Vitamin D for Seasonal Depression?

January 23, 2024

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The dreary winter months can feel like a long slog. In some regions, the winter doldrums last for four months or longer. It’s cold. It’s gray. The days are short. You may be spending a lot of time indoors with no sun or fresh air. If you’re feeling sad, moody, or low on energy, you may be experiencing seasonal depression, also known as seasonal affective disorder.

Those winter blues are typically a recurrent pattern, starting in late fall and ending in springtime, as the days get shorter and then longer again. If you’re experiencing seasonal depression, one way to potentially get some relief is with vitamin D.

Why vitamin D matters

Notably, about 5 percent of U.S. adults (nearly 13 million people) experience seasonal depression, and it can last for up to 5 months. Most of the vitamin D in our bodies comes from our reaction to exposure to the sun’s ultraviolet rays. In the fall and winter, when we have less exposure to sunlight – from shorter days and less time spent outside – we’re more susceptible to deficiency in vitamin D.

Research indicates that maintaining enough vitamin D can be beneficial to mental health, so supplementing with it can be one avenue to explore for relief. (The American Psychiatry Association recommends other treatments for seasonal depression, including light therapy and cognitive behavioral therapy.)

What else can vitamin D do?

Aside from potentially helping with seasonal depression, vitamin D has several other benefits, including increasing bone strength and muscle mass, improving sleep, and boosting overall health, says registered dietitian Michelle Darian.

“Vitamin D and calcium work together to help build strong bones. Strong bones protect our heart and lungs and anchor our muscles,” Darian says. “Vitamin D maintains healthy and strong bones by regulating the absorption of calcium, the major component in bones. Together, these two nutrients also help protect you from age-related bone diseases like osteoporosis later in life.”

Vitamin D is also key to muscle growth and development. “One study found that vitamin D acts directly on muscle to increase protein synthesis, which can lead to an increase in muscle mass,” Darian notes.

Vitamin D’s role in sleep also factors into mood, because not getting enough sleep can increase the risk of depression.

What you need to know about vitamin D for winter depression

Check with your doctor or other health care provider before starting any supplement. Darian recommends checking your blood vitamin D levels before considering a supplement.

Just because some vitamin D may help, doesn’t mean a lot is better. You can get too much of a good thing. “It’s important to note that excess vitamin D may cause weakness, nausea, and poor appetite,” Darian warns. “Studies have also found that too much vitamin D worsens athletic performance, so it is important to test your vitamin D levels before supplementing.”