Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In
Myth-buster

A 24-week trial of folic acid plus 1,600 IU vitamin D failed to improve overall cognition in adults with mild impairment and vitamin D deficiency — though a per-protocol analysis hinted at a possible effect, requiring longer replication.

This open-label, 402-person study is among the first to test this specific combination, and its null result challenges popular hopes that pairing B vitamins with D might boost brain function — but the finding applies only to a narrow clinical group, and the unblinded design means we should treat the hint of an effect with caution until larger, blinded trials weigh in.

Researchers gave people with mild cognitive impairment and low vitamin D levels either folic acid plus high-dose vitamin D or a control for six months. When they analyzed everyone as originally assigned, the combination showed no meaningful advantage over control on tests of overall cognitive function. A secondary analysis that excluded people who didn't fully follow the protocol did find a potential benefit, but that kind of analysis is less reliable and doesn't change the main negative result.

Where this fits in the evidence

This is among the first studies we've indexed on Vitamin B9 for Improved Overall Cognitive Function — treat it as an early signal until more research accumulates.

The study

Effects of Vitamin D3 Combined with Folic Acid on Domain and Specific Cognitive Function among Patients with Mild Cognitive Impairment: A Randomized Clinical Trial.

  • Randomized Controlled Trial (RCT)
  • n = 402
  • 2024-12
  • The journal of prevention of Alzheimer's disease
More on Vitamin B9More on Improved Overall Cognitive Function

This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.

Back to top