Nuun is a company that makes tablets that you dissolve in water to make electrolyte drinks. Dan Moricoli (one of Dr Klimas's patients) mentioned that he takes them to try to keep hydrated. I got some to try last week and used them on a day when I was trying a 500 calorie fast. I found this stuff palatable in a way that I haven't found other electrolyte drinks such as Gatorade. I wouldn't drink Nuun for fun but it's not horrible either. It doesn't contain sugar, which I thought was a good thing, but it contains sorbitol, which is a sugar alcohol. I wondered if I should be concerned about any of the ingredients, including sorbitol. Presumably they're all in small amounts. They're as follows: Active Ingredients Sodium (carbonates) Potassium (bicarbonate) Magnesium (sulfate) Calcium (carbonate) Vitamin C Vitamin B2 level (mg) 360.0 100.0 25.0 12.5 37.5 500 mcg Other ingredients: citric acid, sorbitol, sodium carbonate, natural colors flavors, sodium bicarbonate, potassium bicarbonate, polyethylene glycol, magnesium sulfate, sodium benzoate, calcium carbonate, acesulfame potassium, riboflavin-5-phosphate. Must admit I'd rather be drinking something natural like coconut water but it's incredibly expensive in the UK, at least - it's £3.50/litre - and although it's big on potassium I don't know that it's got the other electrolytes.