More people are taking protein supplements regularly. The widespread understanding is that they aid muscle recovery after exercise, but protein's uses in the body are broader than that.

Ingested protein is broken into amino acids and then allocated to various purposes: synthesis and repair of muscle tissue, but also raw material for enzymes and hormones, production of immune-related proteins, and cell membrane structure.

A minimum intake is therefore necessary even for people who do not exercise. Older adults in particular synthesise muscle less efficiently from the same amount, so recommended intake per unit of body weight is often set higher than for younger adults.

Conversely, excess intake does not automatically become muscle. Surplus amino acids are used for energy or excreted, and because that process can burden the kidneys, it is flagged as a caution for people with kidney disease.

Whether supplements or food are preferable depends on circumstances. The standard explanation is that supplements add little for those who already get enough from meals.

This article summarises general nutritional information. Decisions based on individual health status should be discussed with medical professionals, particularly where an underlying condition exists.