My doctor added vitamin D test to his patients recurring blood work since the start of COVID, and found out just about all his patients was deficient or near it.
If you don't have a primarily fish based diet or spend hours under direct overhead sunlight every day without a shirt on, you're probably deficient as well.
If you don't have a primarily fish based diet or spend hours under direct overhead sunlight every day without a shirt on, you're probably deficient as well.