Vitamin C healthy drink?

I need to take more Vit C .... I was just at Trader's Joes and found this packet that you mix with water to get 1000mg of Vitamin C as well as a few other antioxidants.. Can this be right?? Like I said I need to build up my immunity and this seems perfect with 1000mg of Vitamin C PLUS I have to drink it with 8oz of water which is an extra bonus!!!!!!