I started taking B-12 several weeks ago and have noticed a HUGE difference in the way I feel, my ability to stay awake during the day and my stamina.

It's very important to take the Methylcobalamin (Methyl B-12). Here is a link where I purchase mine.....http://www.iherb.com/Jarrow-Formulas...enges/117?at=0. Their instructions say to take one every 3 or 4 days but I take one tablet every morning. First thing before I eat or drink anything. It's very important to take this particular supplement on an empty stomach. It has helped me more than I even imagined it would. That along with the D3 is a great combination.