My legs feel weak after taking vitamin b12 injections. Is it normal?

It is not uncommon for some symptoms to appear to get worse before they get better as the B12 you are having starts repairing the damage done to your nervous system and your brain starts getting multiple messages from part of the body it had "forgotten about" or lost contact with.

I sometimes liken it to a badly tuned radio on which you have turned the volume up high trying to catch the programme you want when all of a sudden the signal comes in loud and clear and the blast nearly deafens you.

A lot will depend on the severity and longevity of your B12 deficiency as to how long before there is no further improvement or recovery. Some symptoms will "disappear" quite quickly whereas others may take months or even years. There is no set timescale as we are all different.

It is also important that your Folate level is monitored as this is essential to process the B12.

There is a complex interaction between folic acid, vitamin B12 and iron. A deficiency of one may be "masked" by excess of another so the three must always be in balance.

Symptoms of a folate deficiency can include:

symptoms related to anaemia

reduced sense of taste

diarrhoea

numbness and tingling in the feet and hands

muscle weakness

depression

Initially, replacing B12 will lead to a huge increase in the production of blood cells and platelets (which occurs in the bone marrow) and can lead to rapid depletion of folate and iron stores; this can then limit the expected recovery of Haemoglobin.

Both iron and folate may be needed so please have these levels checked by your doctor.

I am not a medically trained person but I've had Pernicious Anaemia (a form of B12 deficiency) for more than 46 years.

I wish you well. 

Yes it's quiet common to feel this ur b12is very low u might have difficulty in walking muscle weakness palpitations depression brain fog memory loss. U might feel better after some 4months plz keep taking injections every alternative day and after that every month once.

It might be that you body needs time to get used to the injections, everything should change within a few weeks, but if not then speak to your doctor.