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Complementary Medicine

Vitamin B12 Deficiency with B12 Supplemnts



I am a 62 y/o male. I just discovered that I have a B12 deficiency(my level was 138). My symptoms included fatigue and demetia type symptoms(memory loss mostly). I am also diabetic and take glucophage. My Physician ordered B12 injections once per month for 3 months and sublingual B12 500 mcg daily. I had my first injection August 24th and started the SL B12 on the 25th. I have yet to feel any increase in energy, decrease in fatigue and the memory is still poor. I spoke with my physicians office staff today( 9/11/07) and was told that it may take 6 weeks to start to feel better. I have read several articles and they all have stated that within 48-72 hours a person should feel more energized. I realize a persons response to B12 is individualized, but how long does it normally take to see an improvement after starting B12 therapy? Thank you so much for your time.


Vit B12 deficiency > 3 months can leave permanent deficits. Having said that most patients respond in a day or two with the half life being 6 days. When patients do not feel a response we add B-100 before each meal and find the mental components return in 5-7 days, but takes months to be perfect.

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Response by:

Glen F Aukerman, MD, DABFP Glen F Aukerman, MD, DABFP
Professor of Family Medicine
College of Medicine
The Ohio State University