Mrs. D is wonderful on the topic, but is sick at this time. You might see if you can find old posts of hers in this forum.

Also, you might consider going to a good health food store and ask someone knowledgeable on the subject. I recall years ago I went to a nutritionist for a few appointments and she told me when in doubt to stick to the brands well known for being good in quality like Jarrow or Solaray.

I take a B Complex, extra B12 and extra B6. I look for a low dose of the extra B6 as I understand too much can be harmful. I take methyl. B12 and look for sublingual or chewable. I do not worry about my dosage of B12 as I understand it is not stored/does not build up and it is safe to take a high dosage.

Additionally, I take a good multi and extra D3.

I have found a multi vitamin along with extra D3 and extra B vitamins very helpful for my issues with mild depression.

Best wishes.