I have found the Solgar methylcobalamin to be the most effective. I got no start-up responses from other brands but did with Solgar. I have trusted Solgar for a long time and they haven't let me down with the meB12 either. As of 3 days ago, I have added in 5mg Lithium Orotate and will up to 10mg tomorrow. When I used LiOr a few months back, it would cause me to empty my bladder a LOT...like, I would have a sip of water and feel the need to go. I read online some people have this effect. I have been on the MeFolate (5mg/day) and MeB12 (5-10mg/day) for many weeks now and although I can't say I really feel any better, I have found the LiOr hasn't caused the above side effect this time. Hence why I am going to try a 10mg dose. I am 30yo and have had CFS following a viral infection at age 8 so I understand it may take a long time for neurology, immune and endocrine systems will take a long time to repair but I am disappointed that I have felt really nothing in the last 6+ weeks of starting methylation protocol.