If you want to add theanine to your EC stack, but it separately IMO. The 2:1 ratio means you’ll be taking 400mg theanine to get 200mg caffeine; that’s a pretty high dose. It’ll be cheaper (per serving) to buy them separately, and will give you the flexibility to dose your caffeine and theanine independently (at whatever ratio you find best, perhaps 2:1, 1:1, or 1:2).