5 Signs You Might Be Low in Vitamin D (And What to Do About It)

Jason Higgins
2026-01-21T10:12:00-05:00

You might be wondering, "What the heck is vitamin D and why do I need it?" Don't worry, we're here to help. Vitamin D is actually a hormone that regulates calcium absorption and phosphorous levels in the body, which are both essential for strong bones.

In addition to keeping your bones healthy, vitamin D has been shown to have a number of other health benefits, including reducing the risk of heart disease, obesity, diabetes, and even some cancers. So clearly, this is one nutrients you don't want to be deficient in. Here are 10 signs that you might be low in vitamin D—and what you can do about it.

1. You Always Feel Tired
Do you find yourself struggling to get out of bed in the morning—even after a full night's sleep? Feeling exhausted all the time can be a sign that you're not getting enough vitamin D. In fact, studies have shown that fatigue is one of the most common symptoms of vitamin D deficiency. If you're always feeling tired, make sure to get your vitamin D levels checked by a doctor.

2. You Get Sick Often
Vitamin D plays an important role in boosting immunity, so if you find yourself getting sick more often than usual, it could be a sign that you're deficient in this nutrient. One study found that people who were deficient in vitamin D were nearly twice as likely to get sick with the flu compared to those who had sufficient levels of the nutrient. So if you're constantly getting sick, get your vitamin D levels checked and consider taking a supplement if necessary.

3. You Suffer from Depression or Anxiety
Low levels of vitamin D have been linked to depression and anxiety. In fact, one study found that people who were deficient in vitamin D were 11% more likely to suffer from depression than those who had sufficient levels of the nutrient. If you've been feeling down lately, make sure to get your vitamin D levels checked by a doctor. And if they turn out to be low, consider taking a supplement or spending more time outside in the sun (more on that later).

4. You Have Trouble Concentrating or Remembering Things
If you find yourself having trouble concentrating or remembering things, it could be a sign of a deficiency in vitamin D. One study found that people with memory problems were significantly more likely to be deficient in this nutrient than those without memory problems. So if you've been forgetting things more often than usual, make sure to get your vitamin D levels checked and consider taking a supplement if necessary.

5. You Experience Muscle Pain or Weakness
Muscle pain and weakness are common symptoms of vitamin D deficiency. In fact, one study found that people with muscle pain were twice as likely to be deficient in this nutrient as those without muscle pain. If you've been experiencing muscle pain or weakness, make sure to get your vitamin D levels checked by a doctor and consider taking a supplement if necessary.

Conclusion:

Vitamin D is an important nutrient that plays a key role in bone health and has also been linked to reduced risk of heart disease, obesity, diabetes, and some cancers. If you're experiencing any of the following 5 signs—fatigue, frequent sicknesses, depression or anxiety, difficulty concentrating or remembering things, muscle pain or weakness—you might be low in vitamin D and should get your levels checked by a doctor along with consider taking a supplement.