Hi Laurel..... 25mg is in each syringe. Yes...it's a huge dose although it was used in one of the studies for ALS....either 25mg daily or 50mg 2x per week. ALS untangled dot com doesn't give an A rating for many reviews although it does for this....lowering homocysteine levels, reducing glutamate toxicity and oxidative stress are all very positive. As far as I know, MB12 is the active form of B12 and is in your system for a much shorter period of time. I would rather over-do it than under-do it. I don't notice any increase in function although since beginning the Deanna Protocol, regular acupuncture and these injections in October I haven't noticed a great deal or progression...knock on wood!! Can't say how much the MB12 has to do with it although would be surprised it isn't having some effect. Also....I now take it with Folic acid oral tablets....apparently MB12 and Folic are synergistic