Vitamin D in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After COVID-19 or Vaccination: A Randomized Controlled Trial.

What Was Tested

This randomized controlled trial looks at Vitamin D, K2, Magnesium and Zinc in the context of chronic fatigue syndrome and me.

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can develop as post-vaccination syndrome (PVS) or Post-Acute Sequelae of SARS-CoV-2 infection (PASC).

In their prior retrospective study, most patients with PVS who developed ME/CFS had vitamin D insufficiency or deficiency.

Who Took Part

The study group was 91 participants.

The age groups tagged for this paper are adults and middle-aged adults, both men and women.

How the Study Was Run

The design is described as randomized and open-label.

Random assignment meant chance, not the researchers, decided who got Vitamin D, K2, Magnesium and Zinc and who got the comparison, which limits bias.

Everyone knew when Vitamin D, K2, Magnesium and Zinc was being given (open label), which is simpler to run but leaves more room for expectations to affect what is reported.

What Was Measured

The primary endpoint was the change in ME/CFS symptom count from screening to Week 12.

The subject headings attached to it are Fatigue Syndrome, Chronic, Vitamin D, Vitamin D Deficiency, COVID-19, Dietary Supplements, Vaccination and SARS-CoV-2.

Author keywords: COVID-19 vaccine, Long COVID, PASC, myalgic encephalomyelitis/chronic fatigue syndrome and post-vaccination syndrome.

What This Means in Plain Language

The paper is a randomized and open-label study of Vitamin D, K2, Magnesium and Zinc in 91 participants in people with chronic fatigue syndrome and me.

The publication is from 2026 (Nutrients), a journal based in Switzerland.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, Chronic fatigue syndrome and ME research.