I also tried the ABR drugs (other than Rebif) and have been on Tysabri going on 9 infusions...Have been Dx's w/MS for about 10 yrs now. I am on Thyroid, Calcium, and an anti-depressant...am 51, female, and although not menopausal yet, hormones do play a big part of how I feel (along with the heat these days!)Anyway, no new side effects, relapses, but I HAVE noticed an energy change...let me explain...my first infusions were in a center where I was done within 3/4 an hour...my last three have been in a center closer to home, and take nearly 2 hrs (smaller needle)...anyway, no noticeable energy surge for the last three...how long does your infusion take?