Hello lybrate-user. Green coffee contains caffeine, similar to regular coffee. Therefore, green coffee can cause caffeine-related side effects similar to coffee like insomnia, restlessness,vometing, increased breathing rate etc.
Depending on the concentration of Chlorogenic acid in your supplement, this can range from a dosage of 240-3000 mg of green coffee bean extract per day. I recommend that you follow the dosage instructions on the bottle. A common recommendation is one serving, 30 minutes before each meal.