My vit d3 level is 15.87 and vit b12 level is 161 My haemoglobin level is 11.8 and RCB count is 4 which is less...my doctor prescribe me meganeuron od plus tablet Along with uprise d3...?but after taking meganeuron od plus for 10 days i have been facing side effect like constipation and loss of appetite... Plz tell me the name of vit b12 medicine which has no side effect like constipation and loss of appetite...tell me the name of vit b12 medicine of top pharmaceutical company which should be easily available...i have poor memory and poor concentration as well