The NHS has said: "Everyone over the age of 1 year should have 10 micrograms (mcg or µg) or 400 international units (IU) of ...

“It’s truly one of the most versatile ingredients we have,” explains board-certified dermatologist Dhaval Bhanusali, M.D.

People you might class as a ‘perfectionist’ or an ‘extremely hard worker’ might actually be showing the signs of something ...