2_gainin may have meant ephedrine/caffeine.
20-30 mg on first dose of the day, with 200 mg caffeine. After that, optionally up to another 50 mg ephedrine per day, preferably in smaller amounts taken more frequently as the half-life is short. Caffeine continues to be taken with it, in proportion.
It's effective while the body is currently absorbing less calories than it's burning. If in a caloric excess or balance, for example in the few hours after a larger meal, it will do less if any good. It can be omitted at such times.