Methylsulfonylmethane (MSM) is a sulfur-containing compound found in plants, animals, and humans. It can also be made in a lab into a dietary supplement, which is used widely in alternative medicine.

While chunky knits and oversized scarves might make wrapping up against autumn's drizz-mal temperatures a stylish breeze, protecting your hair and skin from blasts of icy wind and lacklustre light is ...