Source: Fox News
“Vitamin D is known to be essential to many aspects of human health, but a new study suggests that taking a certain form of it can have a negative effect. The more potent and longer-lasting form, vitamin D3 (cholecalciferol) is produced naturally when the body is exposed to sunlight and is also found in animal products, while vitamin D2 (ergocalciferol) comes from plant or fungal sources, per the National Institutes of Health. Researchers from the University of Surrey in the U.K. found that taking vitamin D2 can cause reduced levels of vitamin D3 in the body. They made this determination by analyzing 11 randomized controlled trials including 655 adults, which showed that people taking vitamin D2 supplements had less vitamin D3 than those who did not take D2, according to a university press release.” (10/13/25)
https://www.foxnews.com/health/popular-vitamin-d-supplement-may-have-unexpected-effect-experts-warn