I have an uber-sensitivity to caffeine and I know there’s only a small amount in the AM formula, so I only need one. I take 2 of the PM to counteract at night. I am still adjusting because they really make my brain go to work, but the results are immediate and significant. When I look back at my work product from before, I started a couple of weeks ago and now, there is a drastic difference in my productivity and quality. Would definitely recommend to others feeling a little foggy and slow.