What is it? It's water that comes from coconuts.

How much does it cost? A ridiculous amount. The price arbitrarily leaps about, but a litre usually costs about £3.50.

What does it promise? Believers claim that it aids digestion, cures hangovers, reduces blood pressure and helps you lose weight.

What's it actually like? My first run-in with coconut water came at the end of a race, where it was thrust into my hands by a well-meaning volunteer. I immediately spat it out, because coconut water doesn't taste anything like normal water. Or at least it would, if normal water came with a leaking battery dropped inside it. It tastes like slightly rancid sweat. But that's part of its appeal – the sugars and salt that make it taste so hideous are what will keep you hydrated. However, coconut water contains calories, so you'll see the effects only if you have an active lifestyle. It won't work if you drink it lying on the sofa next to a pile of cakes.

Best and worst bit The moment you finally learn to like the stuff feels as if it's a genuine breakthrough, like the first time you could drink beer without screwing up your face. However, the various stages of buying it – wondering if you can afford it, wondering if the health benefits are worth the enormous price, the slow crashing wave of unstoppable middle-class guilt as it goes through the checkout, and then the crushing realisation that you don't actually even really like the bloody stuff anyway – undoes this moment of glory in an instant.

Is it worth it? Probably not, in all honesty. Tap water's also quite good for hydration, I hear.