Researchers discovered that teenagers with anxiety disorders tend to have lower vitamin D levels in their blood compared to healthy teens. In this study, 124 anxious teens had significantly less vitamin D than 131 healthy peers. When anxious teens with low vitamin D took supplements for 12 weeks, their anxiety symptoms improved. While this doesn’t prove vitamin D deficiency causes anxiety, it suggests that checking and correcting low vitamin D levels might be a helpful part of treating teen anxiety.

The Quick Take

  • What they studied: Whether teenagers with anxiety have lower vitamin D levels than healthy teens, and whether taking vitamin D supplements helps reduce anxiety symptoms.
  • Who participated: 255 adolescents total: 124 teens diagnosed with anxiety disorders and 131 healthy teens without anxiety. All were patients or visitors at a hospital in China between 2020-2022. Of the anxious teens, 86 with low vitamin D received supplements.
  • Key finding: Anxious teens had an average vitamin D level of 16.48 ng/ml, while healthy teens averaged 22.95 ng/ml—a meaningful difference. After 12 weeks of vitamin D supplements, anxious teens with low vitamin D showed reduced anxiety scores.
  • What it means for you: If you’re a teen struggling with anxiety, getting your vitamin D level checked might be worth discussing with your doctor. Taking vitamin D supplements appears to help reduce anxiety symptoms, especially if your levels are low. However, this isn’t a replacement for other anxiety treatments—it may work best as part of a complete treatment plan.

The Research Details

This was a case-control study, which means researchers compared two groups: teenagers with anxiety disorders and healthy teenagers without anxiety. They measured vitamin D levels in both groups’s blood to see if there was a difference. The researchers then took 86 of the anxious teens who also had low vitamin D and gave them vitamin D supplements for 12 weeks. They measured their anxiety levels before and after the supplements to see if vitamin D helped.

The study took place at a hospital in China from 2020 to 2022. Researchers used blood tests to measure vitamin D (specifically a form called 25-hydroxyvitamin D3) and used standard anxiety questionnaires to measure how anxious each teen felt. This approach allowed them to see both whether anxious teens have lower vitamin D and whether fixing low vitamin D improves anxiety.

Case-control studies are useful for finding connections between health conditions and other factors. By comparing anxious teens to healthy teens, researchers could see if vitamin D deficiency is more common in anxiety. The supplementation part of the study was important because it showed that vitamin D might actually help reduce anxiety, not just that low vitamin D happens to occur with anxiety. This type of evidence helps doctors decide whether checking and treating vitamin D deficiency should be part of anxiety care.

This study has several strengths: it included a reasonable number of participants (255 total), used objective blood tests to measure vitamin D, and included a follow-up period where teens took supplements. However, there are limitations to consider. The study was done in one hospital in China, so results might not apply equally to all populations. The study didn’t have a control group that took a placebo (fake pill), so some improvement might be from expecting to feel better rather than the vitamin D itself. The researchers didn’t track other factors that might affect anxiety, like exercise, sleep, or other treatments teens were receiving.

What the Results Show

The main finding was clear: teenagers with anxiety disorders had significantly lower vitamin D levels than healthy teenagers. The anxious group averaged 16.48 ng/ml of vitamin D, while the healthy group averaged 22.95 ng/ml. This difference was statistically significant, meaning it wasn’t likely due to chance.

When researchers looked at the relationship between vitamin D levels and anxiety severity in the anxious teens, they found that lower vitamin D was associated with higher anxiety scores. In other words, the teens with the lowest vitamin D tended to have the most anxiety symptoms.

The most encouraging finding came from the supplementation part of the study. When 86 anxious teens with low vitamin D took supplements for 12 weeks, their anxiety scores decreased. This suggests that raising vitamin D levels may help reduce anxiety symptoms in teenagers who are deficient.

The study showed that vitamin D deficiency or insufficiency was common among the anxious teens studied. The researchers found that vitamin D levels could predict anxiety scores to some degree—meaning vitamin D status had a measurable relationship with how anxious someone felt. This suggests vitamin D might be one of several factors worth considering when evaluating teen anxiety.

This research adds to growing evidence that vitamin D may play a role in mental health, particularly anxiety and depression. Previous studies in adults have suggested similar connections between low vitamin D and anxiety, but research specifically in teenagers has been limited. This study provides some of the first evidence that the vitamin D-anxiety connection may also apply to adolescents. The findings align with the theory that vitamin D affects brain chemicals involved in mood and anxiety regulation.

Several important limitations should be considered. First, this was a relatively small study in one hospital in China, so results may not apply to all teenagers everywhere. Second, the study didn’t use a placebo control group—some teens got supplements while others didn’t, but researchers didn’t give some teens fake pills to compare. This means some of the improvement might come from expecting to feel better rather than the vitamin D itself. Third, researchers didn’t track other things that affect anxiety, like sleep quality, exercise, stress levels, or whether teens were receiving other treatments. Fourth, the study was observational for the comparison part, so we can’t be certain that low vitamin D causes anxiety—it could be that anxiety causes low vitamin D, or both could be caused by something else. Finally, the follow-up period was only 12 weeks, so we don’t know if benefits last longer.

The Bottom Line

If you’re a teenager with anxiety, discuss vitamin D testing with your doctor. If your levels are low, vitamin D supplementation appears to be a safe, inexpensive addition to anxiety treatment that may help reduce symptoms. However, vitamin D supplements should not replace other proven anxiety treatments like therapy or medication if your doctor recommends them. The evidence suggests vitamin D supplementation is most helpful as part of a complete anxiety treatment plan. Confidence level: Moderate—the research is promising but limited by study design and size.

This research is most relevant to teenagers experiencing anxiety symptoms and their parents or guardians. It’s also important for doctors and mental health professionals who treat teen anxiety. Teenagers with other mental health conditions like depression might also benefit from discussing vitamin D levels with their doctors, though this study specifically focused on anxiety. This research is less relevant to teens without anxiety symptoms, though maintaining adequate vitamin D is important for overall health.

Based on this study, you might expect to see some improvement in anxiety symptoms within 12 weeks of starting vitamin D supplementation if your levels are low. However, individual results vary. Some people may notice improvements sooner, while others may take the full 12 weeks. It’s important to continue other anxiety treatments while starting vitamin D and to work with your doctor to monitor progress.

Want to Apply This Research?

  • Track your anxiety levels weekly using a simple 1-10 scale and note your vitamin D supplementation. Record specific anxiety symptoms (like worry, nervousness, or physical tension) to see if they improve over 12 weeks of supplementation.
  • Set a daily reminder to take your vitamin D supplement at the same time each day (like with breakfast). Log each dose in the app to build consistency. Also track any anxiety-related activities like meditation, exercise, or therapy sessions alongside your vitamin D intake to see how these factors work together.
  • Create a weekly anxiety check-in where you rate your overall anxiety, note any improvements in specific symptoms, and confirm you took your vitamin D supplement consistently. After 12 weeks, compare your starting anxiety scores to your current scores to measure progress. Share this data with your doctor to help guide ongoing treatment decisions.

This research suggests a potential connection between vitamin D and teen anxiety, but it is not definitive proof that vitamin D deficiency causes anxiety or that supplements will cure anxiety in all cases. This information is educational and should not replace professional medical advice. If you or a teenager in your care is experiencing anxiety, please consult with a qualified healthcare provider, mental health professional, or doctor before starting any supplements. Vitamin D supplementation should be part of a comprehensive anxiety treatment plan, not a standalone treatment. Always discuss any new supplements with your doctor, especially if you’re taking other medications. Individual results may vary, and what works for one person may not work for another.