I have been using zipfizz for 13 years. I am 65. I tend to carry my stress in my neck, which can cause headaches, even migraines. I began taking this when I was helping my sister and brother-in-law move. She offered me one. I drank the whole thing. I noticed it caused me to relax a bit, just enough for me not to get a headache. It did keep me up all night that first time. Since then, I use 1 bottle a day, 1/3 morning, 1/3 noon, 1/3 3pm. This combination seems to be perfect for me. I work hard physically on the farm and find it gives me steady energy through the day. For me, the benefits outweighed the Splenda being in it.