However, there is currently no strong scientific evidence proving that placing soap in or under your bedsheets actually prevents leg cramps. While some people report noticeable improvements, these experiences do not establish that soap itself is responsible for the effect. The remedy may also work as a psychological comfort. Having a familiar bedtime routine can make people feel more relaxed, and relaxation may make it easier to fall asleep.

In that sense, the soap could become a comforting ritual even if it has no direct physical effect on muscle cramps. People who try the trick generally choose a plain or lightly scented bar and keep it dry. Anyone with sensitive skin should avoid strongly perfumed products that could cause irritation, particularly if the soap comes into direct contact with the body.