Does vitamin D help with blood pressure? What the research does and doesn't show

Pooled randomised trials do not show that vitamin D supplements lower blood pressure in general. A meta-analysis of 46 trials (4,541 people) found no effect on systolic or diastolic pressure. Smaller analyses in people with high blood pressure and low vitamin D found a drop in systolic pressure, mostly at very large doses.

What the evidence doesn't support

• No evidence of an effect on blood pressure in people at large. The 46-trial analysis found an effect size of 0.0 mm Hg for systolic pressure (95% CI -0.8 to 0.8).
• No evidence for use in high blood pressure. The more positive analyses were limited to people with high blood pressure and low vitamin D, and their authors asked for better trials.
• Everyday doses doing what very large doses did. The signal in the hypertension analysis was in trials using doses above 400,000 IU in total, not daily doses at the label level.
• A reason to expect vitamin D to raise blood pressure at ordinary doses. We found no trial reporting this either, which is a different point from the question of a fall.
• No evidence on vitamin D3 with K2. We found no trial of the pair to cite.

What the trials found

All trials pooled: no effect

A 2015 systematic review and meta-analysis in JAMA Internal Medicine combined 46 randomised placebo-controlled trials (4,541 participants) of vitamin D supplementation lasting at least 4 weeks, for any indication, with active or inactive forms of vitamin D allowed. Trial-level results showed no effect on systolic pressure (0.0 mm Hg, 95% CI -0.8 to 0.8) or diastolic pressure (-0.1 mm Hg, 95% CI -0.6 to 0.5). Individual-patient data from 27 trials (3,092 people) agreed, and no baseline characteristic predicted a better response. The search ran to March 2014, and doses and forms varied between trials, so it cannot speak to newer trials or to any one dose.

People with high blood pressure and low vitamin D: a possible drop in systolic pressure

A 2024 meta-analysis in the Journal of Hypertension pooled 14 trials (11 in the meta-analysis) in people who had both high blood pressure and low vitamin D. Vitamin D reduced systolic pressure but not diastolic pressure overall. The reduction was clearer in people over 60, in trials longer than 8 weeks, in weekly rather than daily dosing, and in trials using total doses above 400,000 IU. The authors called for well-designed trials to validate the finding. This is a narrow group on very large doses, not the general population and not a daily supplement dose.

Older adults: no overall effect, a subgroup signal

A 2020 meta-analysis in F1000Research of trials in adults over 60 found vitamin D raised blood 25(OH)D but made no significant difference to systolic or diastolic pressure overall. In subgroups, systolic pressure was lower by 4.01 mm Hg (95% CI -7.45 to -0.57) in those with high blood pressure and by 1.91 mm Hg (95% CI -3.48 to -0.34) in those with low vitamin D. Subgroup results are weaker evidence than the overall result.

Cardiovascular events: no effect at 2,000 IU

VITAL (25,871 US adults aged 50 and over, 2,000 IU of vitamin D3 a day, median 5.3 years) found no effect on major cardiovascular events (hazard ratio 0.97, 95% CI 0.85 to 1.12). That is not a blood pressure result, but it is the largest trial at a common supplement dose, and it found no cardiovascular benefit.

Analysis	Who	Systolic pressure
JAMA Intern Med 2015, 46 trials	4,541 people	No effect (0.0 mm Hg, -0.8 to 0.8)
J Hypertens 2024, 11 trials	High blood pressure and low vitamin D	Lower; clearer at very large weekly doses
F1000Research 2020	Adults over 60	No overall effect; subgroup signal

Questions people ask

Does vitamin D3 lower blood pressure?

In the largest pooled analysis, 46 trials, no. Analyses limited to people with high blood pressure and low vitamin D found a lower systolic pressure, mainly at very large doses, and called for confirmation. Neither supports taking a supplement to lower blood pressure.

Can vitamin D3 raise blood pressure, or can too much vitamin D3 raise it?

None of the trials above reported a rise in blood pressure from vitamin D, and the 2015 meta-analysis found no effect either way. What too much vitamin D does cause is high blood calcium: a 2018 clinical review lists confusion, apathy, recurrent vomiting, abdominal pain, frequent urination, thirst and dehydration, and does not list high blood pressure. A 2023 meta-analysis of 22 trials (12,952 adults, 3,200 to 4,000 IU of D3 a day for six months or more) found hypercalcemia more common than on control (relative risk 2.21, about 4 extra cases per 1,000). The adult upper limit is 4,000 IU (100 mcg) a day from all sources; see how much vitamin D is too much.

How does vitamin D3 affect blood pressure?

We cite no mechanism study, so no statement is made about how. The trials above measured the outcome and, pooled, found no effect.

Does vitamin D3 and K2 lower blood pressure?

We found no trial of the combination to cite. See magnesium glycinate with vitamin D3 and K2 for what is and is not known about the pairing.

Is vitamin D3 good for high blood pressure?

The evidence does not show that it is. People with high blood pressure who take medication should not change it, and should ask a doctor before adding supplements; see vitamin D interactions.

When to talk to a doctor

High blood pressure usually has no symptoms and is found by measurement, so it needs checking and, if raised, management by a clinician. Vitamin D is not a treatment for high blood pressure, and nothing above supports replacing medication or lifestyle advice with it. If you take blood pressure medication, are pregnant or nursing, or take any other supplement containing vitamin D or calcium, ask a doctor before starting. A blood test of 25-hydroxyvitamin D shows your vitamin D status.