Watermelon juice contains several ions, primarily potassium, magnesium, and calcium. These ions are essential for maintaining hydration, electrolyte balance, and overall health. Potassium, in particular, is crucial for muscle function and nerve signaling, while magnesium and calcium play roles in bone health and muscle contractions. According to a study published in the Journal of Food Composition and Analysis, watermelon juice has an average potassium content of 118 mg per 100 ml, making it a good source of this vital mineral. Additionally, the same study reported magnesium and calcium contents of 4.6 mg and 1.8 mg per 100 ml, respectively. These findings highlight the importance of watermelon juice as a natural source of essential electrolytes.