I also have not tried it as part of the lemonade, but use it by the teaspoon when I'm feeling weak. Especially during that time of the month, as I tend to be slightly anemic anyways. Today I had to take 3 teaspoons at different times and each time I felt less fatigued and was able to continue with my difficult day.
I completed several MC's before I read a suggestion to use it as I am now. Ever since, I can say that the Master-Cleanse is MUCH easier to get through! Try it!