I started off at 10 then found it wasnt doing enough (6' 195) so I went to 15 then 20 .. but yes I got the lower back pain too.. and knee joint. Had to slow my cardio. Went to 204 now 2 weeks after back to 195. Kept some of the strenght but when I was on the last week rocked. If I was to do it again at my size id start at 20.

Sides were too much though. Got my Methyl-D already. Antother 2 weeks and I am on that.