I really LOVE these lemonade packets! I use two packets in my 40oz water bottle multiple times a day, and it's helped me drink a lot more water than I was before these packets. It's really tasty, not too strong, and doesn't have that weird aftertaste that some low-calorie or sugar-free products often have. If I only use one packet for the 40oz of water, it just gives a slight lemon aftertaste without much flavor, which I personally don’t like, but others might.. It's not an exact science on how much to use. Totally worth the money