Popular Vitamin D Supplement Has “Previously Unknown” Negative Effect, Study Finds

A new meta-analysis of randomized controlled trials suggests vitamin D2 supplements may lower vitamin D3 levels in the body.

The review indicates vitamin D3 may be more effective than D2 at supporting overall vitamin D status and immune-related pathways.

Researchers from the University of Surrey and collaborators say the findings challenge the idea that D2 and D3 are interchangeable.

The result could influence supplement guidance for bone health and immune support.