Hi Velha, Is it normal, in what you know about peoples experience, to have worsenibg of focus and short term memory during startup? I'm having a general worsening it seems and am not sure how long to stay the course. Yes, worsening and intensification and shifting of symptoms is the usual course of what happens when starting active b12s from a severe deficiency state. However, it's like the weather. It changes again and again and again. The startup period is most like that as the sudden startup of so many processes put a heavy load on the body's resources and can cause temporary shortages of other factors and brings verious things to a grinding halt that just barely started up. As some things heal, and epithelial tissues that are normally fast reproducing, are usually the fastest to heal. After those heal and changes often occur with the blood ands immune system, things settle down quite a bit. Neurological healing takes the longest. In neurological things, the roller coaster effect is especially noticable as something is still damaged until the last step of healing it takes place and so it goes from one damaged state to a different damaged state. In my experience everything that is affected during the startup is improved or healed over time. The things that are totally unaffected may or may not be changed over time. Not everything is related to b12 deficiencies and as the many things that are fall away the remaining things are more clerarly revealed. The tendency of the active b12s is for things to go towards normal but it's like a new driver with a stick shift, uneven and jerky on the starts and shakey on everything else.