Thyroid UK
82,948 members97,982 posts

What dose of vitamin b12 is ok to start with?

I havent had my vitamin levels tested yet so i suppose this is a silly question but i am willing to try anything to feel better and get rid of my anxiety symptoms on levo. I recently read about vitamin b12 being vital when you are hypo but i dont know what dosage to take to start with. What is classed as high strength?

3 Replies

tricky question really, as you should get tested first (not silly 'tho) if you supplement successfully then get tested doc will think levels are OK, although it could be other stuff. Same goes with irons, folate, ferratin & Vit D etc. (possible underlying deficiencies).

I can only speak from my experience really, doc wouldn't do Vit D3 (or B12) test so I had a private (NHS) spot-test for Vit D ('inadequate') & told doc, who, although interested said just go to boots - since supplementing I feel better - but you have to get someone to take your bloods for Vit B12 & it's more complicated so I haven't got my head round it yet - however it is an option - suggest you ask your GP first? otherwise try the main site for info

J :D


Hi, Poshbird

It really is not a good idea to start taking supplemental B12 before any tests are run, which they certainly should be as you are hypothyroid, because your intake of B12 will skew the results. If I were you, I'd wait until B12 is tested, when folate and ferritin will also be tested, plus a full blood count and if you are lucky, Vit D also.

However, bitter experience has taught me to have a most cynical and suspicious mind so please ask for copies of the blood test results, never trust any doctor who says "Your blood test results are normal." I did, but never again, had just about every symptom listed on but was refused any treatment despite having umpteen symptoms and told if I was looking for symptoms I would find them. The arrant stupidity!! Fixed myself eventually, and still do, but it is necessary to know exactly what you are doing - what to take, how to take it, and why, to fix yourself efficiently. Always get copies of your blood test results, you are entitled to them, and then post the results here in full with all reference ranges also (very important) and then we can advise you.

Go to:

for B12 Sign & Symptoms Assessment

It would also be useful if you would post your thyroid test results with ranges and also how much levo you are on. Sometimes anxiety can be because the levo dose is too low but we need to know details before anyone can surmise what is going on.


Dratted proof reader! "for B12 Signs...."


You may also like...