Calcium is sometimes used to support or treat leg cramps, particularly in the context of muscle cramping associated with pregnancy or certain medical conditions. The rationale is based on calcium's key role in muscle contraction and nerve signaling. Deficiency in calcium can lead to increased neuromuscular excitability, which may manifest as muscle cramps or spasms. Thus, correcting a calcium deficiency may alleviate cramps in those specific cases.

However, the scientific evidence supporting routine calcium supplementation for leg cramps in the general population is limited. A few studies have shown that calcium supplementation can help reduce cramping in pregnant women, especially when they have low calcium levels. For example, a Cochrane review (Cochrane, 2012) found some benefit in pregnancy-related cramps, but evidence for non-pregnant adults is weak or inconclusive. For most people, especially those with normal calcium levels, supplementation does not seem to significantly reduce the frequency or severity of leg cramps.

In summary, calcium is scientifically justified in treating leg cramps only when there is a documented deficiency or in certain populations (like pregnant women). Routine use for leg cramps in the general adult population lacks strong evidence and is not broadly recommended.