yep, you can leave out the lemon. Sometimes I use lime just for variety. Or just use mollases and ACV for the macro and trace minerals.
Cayenne pepper should not be taken for more than a month daily. Lemon is a sour food, and sour foods can weaken the spleen over time, but how long that takes is anyone's guess. When it no longer seems tasty or refreshing to you, take a break. I find that I crave sour foods more in the summer, and that is when they are more appropriate. But really, the only overdose possible is the cayenne pepper, as that is one powerful agent! :)