Vitamin D is essential for bone strength, immune function, and muscle performance. But despite its importance, many people ...

Taking vitamin D on an empty stomach is likely safe, but absorption may be lower and some people may experience mild stomach ...

When the days shorten and the sun sinks low in the sky, that familiar winter slump sets in. There's a fundamental reason for this seasonal fatigue: low levels of vitamin D—the "sunshine vitamin." ...

Plus, the best ways to supplement your body if you find out you're deficient.