Hi I have just been diagnosed with an under active thyroid (sorry don't have the results to publish). My GP has started my on 50mg of Levo per day and I am back in 4 weeks for another round of bloods. My GP also told me that although my vitamin B12 level was 'normal' it was in the low end therefore it would be beneficial to take a B12 supplement. Could anyone advise/recommend a decent supplement? Also I have experienced slight diarrhoea since starting the Levo, is this normal? Many thanks and I look forward to reading all the posts on this site!