I’m a big believer in Vitamin C. It’s one of those "just generally good for you" vitamins that your body can’t manufacture itself and which needs constant topping up. I eat a lot of fruit anyway but there’s no harm in getting a bit extra.
This is a huge bag and at a very reasonable price. It’ll probably last me years. What I do is mix about half a teaspoonful in a glass of fizzy spring water. This produces a refreshing drink, with a hint of lemon flavour but which has next to no calories and no other nasty junk in it.
One word of warning though: If you’re not taking Vitamin C already, or you don’t eat much fruit, you may want to be standing within sprinting distance of a toilet the first time you take this –or else start with 1/4 or 1/8 of a teaspoonful and work your way up to a bit more, as your body becomes accustomed to it!