The greatest difference would be the stimulant effects it has. It is a great thermo when stacked with other ingredients (i.e. caffeine). If you supplement 12.5mg e with 200mg c OR 25mg e 200mg c, you will have greater a greater thermo effect with the ladder. However, more necessarily does not mean better. I wouldn't dose higher then 25mg at any one time and don't surpass 100mg ephedrine hcl on any given day