It’s not called the “sunshine vitamin” for nothing. Vitamin D is one of the only vitamins that you don’t get primarily through food. Instead, it’s produced from your skin cells, and then processed by other parts of your body (including the liver).

Sadly, a lot of people are deficient! And they tend to get a lot more deficient in the winter with less sunlight, shorter days, and staying inside more.

If you knew the benefits of vitamin D (and specifically of taking vitamin D3 supplements during the winter), you might think twice about getting enough heading into winter. Here are 3 compelling reasons why you should take vitamin D3 during wintertime.

Vitamin D keeps away the winter blues

Scientists have discovered something else special about vitamin D. Not only is it created by sun exposure, but it also functions just like a hormone— and, in some ways, like a happiness neurotransmitter.

That happy feeling after spending some time in the sun? Yep, turns out it may be thanks to the vitamin D. Studies also show it may be good for dispelling depression, a common struggle for many of us during wintertime, and it is even being considered as an important treatment for major depression disorders.

In short, taking vitamin D3 could help keep away those winter blues.

Vitamin D protects your immune system

There are more than a few reasons why cold and flu season blows up in the winter. One reason is we spend more time indoors, increasing its spread. But the other reason is because we’re more susceptible to it, thanks to a natural dip in winter vitamin D.

To reverse this and keep your immunity strong, vitamin D is one of an important handful of nutrients crucial to reducing your risk of colds, flu, and other viral illnesses. It can’t cure, treat, or 100% prevent viral illnesses, but research does show it can reduce your risk, lessen symptoms, and help you deal with it faster and with a quicker recovery time.

Vitamin D supports a healthy weight

Besides the winter blues and more colds and flus, winter is also that season when some of us get a little soft! Good news: vitamin D3 supplements may help with that, too.

It’s not 100% clear why, but studies have found that people were more likely to lose weight if they took vitamin D3 supplements compared to if they led the same lifestyle but took a placebo. It may have to do with how vitamin D helps boost calcium intake, which can help those who don’t get enough calcium lose weight.

Winter is coming. When it does, a lot of us struggle with the blues, depression, mood changes, weight gain, and getting sick often. But it might be because you’re vitamin D deficient!

Taking vitamin D3 supplements this winter can be a great way to combat this— as well as getting outside and getting some sun exposure on sunny winter days when you can.