Coffee is a caffeinated drink that is popular worldwide. The question of whether coffee is hydrating or not has been a topic of debate. Here is what the search results say:

Positive:

• According to a report by the National Academies of Sciences, Engineering, and Medicine, coffee and tea contain mostly water and can be hydrating.
• A study published in the journal PLOS ONE found that coffee can contribute to daily fluid intake and does not lead to dehydration.

Negative:

• Caffeine is a diuretic, which means it can cause you to urinate more frequently, leading to fluid loss.
• Energy drinks, which contain caffeine, as well as other ingredients such as taurine and guarana, do not hydrate and should not be confused with sports drinks.

Ingredients or materials:

• Coffee contains caffeine, which is a drug that stimulates the brain and nervous system.
• Caffeine is naturally found in the leaves and fruits of some plants, including coffee beans, black and green tea, cocoa, cola soft drinks, and energy drinks.
• Caffeine (anhydrous or containing one molecule of water of hydration) is available in a USP grade with the following specifications: it contains not less than 98.5% and not more than 101.0% of the above ingredient calculated on an anhydrous basis.

In conclusion, coffee contains caffeine, which is a diuretic and can cause fluid loss. However, coffee and tea contain mostly water and can be hydrating. It is still a good idea to drink enough water no matter how much coffee you consume. Energy drinks, which contain caffeine and other ingredients, do not hydrate and should not be confused with sports drinks.