My glabella and forehead both need Botox. How many units would I need to have a natural looking forehead?

• I'm fairly conservative with Botox injections into the forehead for the horizontal lines that you are concerned about.  I usually begin with 12 units.  We can always add more later, but I want to make sure that we don't cause ptosis (sagging) of your brows. 
• As far as the glabella region (the lines between your eyebrows) I usually use 20 units.