According to several sources, including studies conducted by St. Andrews University in Scotland, the most hydrating drinks are those that contain a small amount of sugar, fat, or protein, as these ingredients help the body retain water for a longer period of time than plain water. Here are some of the most hydrating drinks, ranked from most to least hydrating:

• Milk (both skim and whole)
• Oral rehydration solutions that contain small amounts of sugar, sodium, and potassium
• Tea
• Sports drinks
• Fruit-infused water
• Fruit juice
• Watermelon juice

Its important to note that while some drinks may be hydrating, they may also contain high amounts of sugar, caffeine, or other ingredients that can have negative health effects. For example, energy drinks are not hydrating and can actually cause dehydration due to their high caffeine content. Its also important to stay away from drinks that can cause water loss, such as sugary sodas.