Does Vitamin D help migraine frequency? (Grade B evidence)
Grade B for Vitamin D on migraine frequency: the balance of RCT evidence favours a benefit, especially in adults with migraine, at moderate certainty, at doses varies across trials.
Bottom line. Grade B for Vitamin D on migraine frequency: the balance of RCT evidence favours a benefit, especially in adults with migraine, at moderate certainty, at doses varies across trials. [1 RCT]
- Direction
- benefit
- Magnitude
- Meta-analysis of 5 RCTs: vitamin D treatment significantly reduced headache days, attack frequency, headache severity, and migraine-related disability versus control in migraine patients. One of the more consistent positive signals for a vitamin D outcome in this dataset, though the evidence base is still just 5 trials.
- Grade
- B
- Certainty
- moderate
- Clinical meaning
- small but potentially useful
- Who it applies to
- adults with migraine
- Dose / form studied
- Safety
- none identified in this claim
- The one limitation
- Sample sizes are small in most included trials; effect sizes may shrink with larger studies.
Reviewed · Evidence last changed · Claim clm_ec_b10-vitd-migraine v1
Grade B / moderate: probably helps, and new studies are unlikely to reverse this — but could shrink the effect size.
Who it works for
Best-studied in adults with migraine. Effective doses cluster around varies across trials.
Evidence
| Study | Design | Cite |
|---|---|---|
| The Efficacy of Vitamin D Supplementation for Migraine: A Meta-Analysis of Randomized Controlled Studies. | peer-reviewed | PMID:33449474 |
Why this grade
Reasoning trace
Grade B at moderate certainty. The grade reflects the direction and size of the effect across the 1 publishable source above; certainty reflects heterogeneity, sample sizes, and design quality. What would move it upward: additional well-powered RCTs in the target population that replicate the effect at similar doses. What would move it down: a large null trial, discovery of publication bias, or a retraction of a keystone study.
Dose & form
Studied intake: varies across trials.
How it stacks up for migraine frequency
- Vitamin D vs Magnesium for migraine frequency — Magnesium Grade C
- Vitamin D vs CoQ10 for migraine frequency — CoQ10 Grade B
- Vitamin D vs Melatonin for migraine frequency — Melatonin Grade C
- All interventions graded for migraine frequency →
Grade history
No grade changes yet. Initial grade assigned; re-reviewed on every 12 months (Grade A/B) — next review by . Methodology v1.
Re-review cadence: every 12 months (Grade A/B) · next scheduled by · methodology v1.
Frequently asked
How long does Vitamin D take to work for migraine frequency?
Trials of Vitamin D for migraine frequency typically report effects within 2–4 weeks, though individual response varies. Studies rarely find benefit inside 1 week for chronic outcomes.
What dose was used in studies of Vitamin D for migraine frequency?
Studied doses for Vitamin D in migraine frequency trials cluster around varies across trials. See the dose block for the specific range and how it varies by form.
Does Vitamin D work for migraine frequency if I'm not deficient?
The effect concentrates in adults with migraine. If your baseline is normal, expect a smaller effect than the trial averages.
Vitamin D or the next-best alternative for migraine frequency?
See the compare block above for the head-to-head with the most-cited alternative. Grade + certainty differences matter more than any single trial.
Related
- Vitamin D for mood — Grade C
- Vitamin D for bone health — Grade B
- Vitamin D for immune function — Grade C
- Vitamin D for strength — Grade C
- Vitamin D for cognition — Grade C
- Vitamin D for testosterone / hormone levels — Grade C
- Full profile: Vitamin D
- Is Vitamin D hype?
- Everything graded for migraine frequency
What this is — and is not
- Evidence description
- Meta-analysis of 5 RCTs: vitamin D treatment significantly reduced headache days, attack frequency, headache severity, and migraine-related disability versus control in migraine patients. One of the more consistent positive signals for a vitamin D outcome in this dataset, though the evidence base is still just 5 trials.
- Substrate's interpretation
- Grade B at moderate certainty — the direction and size the studies converge on, as our reading of the corpus.
- Discuss with a clinician
- If you're on medication or have a condition that changes the calculus, bring the interaction & population blocks above to your pharmacist or prescriber before deciding.
- Individualized medical advice
- Not provided here or on any Substrate surface (API, agent tool, embed) — see YMYL policy.
Cite this page
Reuse under CC-BY 4.0 with attribution to evidencebased.info.
Plain-text citation
Substrate. Does Vitamin D help migraine frequency? (Grade B). https://evidencebased.info/interventions/vitamin-d/migraine. Updated 2026-07-16.
BibTeX
@misc{substrate_ionsvitamindmigraine,
author = {Substrate editorial},
title = {Does Vitamin D help migraine frequency?},
year = {2026},
url = {https://evidencebased.info/interventions/vitamin-d/migraine},
note = {Grade B, evidencebased.info}
}Found something wrong on this page? Report an error →