What: Glucosamine, a sugar that’s present in the hard shells of crustaceans and animals’ bones, is a precursor to one of the major components of the cartilage that cushions joints.
Where: Almost all multi-ingredient joint supplements contain glucosamine, often in combination with chondroitin and a compound known as MSM (which is short for methylsulfonylmethane).
Why: Joints are one of those things that tend to get attention only when they demand it. And when they do, they’re not shy, often by aching or, worse, emitting sharper pains. Regularly taking a joint supplement can help strengthen joints, reducing pain and preventing injury and inflammation. Glucosamine provides joints with the raw materials for making glycosaminoglycans, which are a key component of cartilage. With more cartilage to cushion your joints, you should be able to go back to ignoring them.