Taking more makes it last longer. It will only be stronger if the 40 wasn’t strong enough in the first place (exactly what happened with me). I take three capsules of the 40, all at once in the morning. Taking one tablet wears off after5 hours, two tablets wears off after 9 hours, three tablets wears off after 13 hours. That’s just to give you an example. Each person requires a different dose and metabolizes at a different rate.