Vitamin D Supplements and Anxiety: What the Evidence Says

What the evidence shows

A review of adult trials found no significant effect of vitamin D3 on anxiety symptoms.
A trial in people with post-COVID symptoms found lower anxiety scores after vitamin D.
A Parkinson’s disease trial found lower anxiety after vitamin D and probiotics together.
The guideline review found insufficient evidence for nutraceuticals in anxiety-related disorders, with a separate exception for N-acetyl cysteine in obsessive-compulsive disorder-related conditions.

What the research says

Research results differ across the studies summarized here. A review of adult trials found no significant effect of vitamin D3 on anxiety symptoms. A trial in people with post-COVID syndrome found lower anxiety scores after vitamin D. Another trial found lower anxiety after participants with Parkinson’s disease took vitamin D with probiotics.

Results across adult trials

A 2024 review combined results from 31 randomized trials with 24,189 adults. It examined vitamin D3 and both depressive and anxiety symptoms. The review found no significant effect on anxiety symptoms. Its follow-up groups included trials lasting 8 weeks or less, 8 to 24 weeks, and 24 to 52 weeks. They also included trials lasting more than 52 weeks. The abstract reports stronger effects on depression in the first two groups, but not in the longer groups. It calls for more high-quality trials to assess anxiety.

Studies in specific patient groups

An 8-week randomized trial studied 80 patients with post-COVID fatigue or neuropsychiatric symptoms. Compared with a dummy pill, the vitamin D group had lower anxiety scores. The study also found improvements in fatigue and cognitive scores. It found no significant group differences in sleep quality, depression scores, trail-making tests, or two inflammation markers. Adverse events were similar, and no serious adverse events were reported.

A 12-week randomized trial studied 46 people with Parkinson’s disease. Participants received vitamin D with probiotics or dummy pills. The combined supplement group had lower anxiety scores, disease severity, and gastrointestinal problems than the dummy-pill group. The abstract does not give the size of the anxiety change.

What a clinical guideline review found

A 2022 guideline review assessed evidence from meta-analyses and randomized trials for psychiatric conditions. It reported that no nutraceutical had sufficient evidence for any anxiety-related disorder, apart from its separate finding. That finding concerned N-acetyl cysteine in obsessive-compulsive disorder-related conditions. The review assessed Grade A evidence, defined as a meta-analysis or two or more randomized trials. Its findings describe that evidence review; they do not report results from a new vitamin D anxiety trial.

Sources

About this article

NootroWorld publishes research summaries, not medical advice. This article describes what studies have and have not established; it does not tell you what to take. Supplements can interact with medication, pregnancy and existing health conditions, and study populations often differ from your own situation. Discuss any personal decision with a qualified healthcare professional.