After 40 years of smoking ultra light cigarettes, I went exclusively to SmokeTip, and E-cig.  It has been 5 months, and I love it.  However, the past month I have had numbness and tingling in my lower legs and feet, and in my hands. Has anyone else experienced this.  I use about 4 cartriges per day (6mg each). 
Thank you!  Great site!