There have been a lot of favorable mentions of AOR. What is needed is some serious A-B testing despite the ENZY not being avaialble easily in quantity. If half a dozen people, sensitive to the differences could do a couple of planned A-B comparisons, and then A-B each pair of brands, it would produce some good info. Another candidate is the Kirkland methylcobalamin 5mg x 300 tablets for $19 at Costco and $25 at Amazon. Another is Medicine Shoppe housebrand MeCbl, 1000mcg and other sizes if available. We, and I mean A LOT OF US, need these trials. We need fallbacks and alternates on brands so we don't get clobbered by things like the Jarrow change. I found the Jarrow originally because the ENZT went out of stock everywhere for several months after the first time I named it as truely superior. I had a month of relapse before identifying it. I ordered 10 brands all at once. During that first year I had best results taking 2-4 brands at the same time and identifying the best combinations.