It has many substances that it shouldn't have since it is supposed to be just a caffeine supplement. Also, caffeine is absorbed from 0 to 100%. That means that when you are relaxed while reading or at the gym, suddenly you have a rapid heartbeat for forty minutes and then the effect stops. I suggest finding a slow-release caffeine supplement or drinking beverages with caffeine instead, as this way of taking caffeine does more harm than good.

After 5 uses, I noticed that it caused swelling in my stomach and irritation in my throat, which I assume is an allergy. Maybe it's something subjective. I always took the pill with food and water.

Very good product. It has 100mg which correspond to 133% of the caffeine in a Red Bull or 67% of that in a Monster. I use it instead of pre-workout with a light meal/snack.