Vitamin B-12, also known as cobalamin and cyanocobalamin, is one of the eight B-complex vitamins. Vitamin B-12 is necessary for metabolism, DNA synthesis, production of red blood cells and maintenance of healthy nerve cells, according to FamilyDoctor.org.
www.livestrong.com
I'm not saying I trust this or any statement at all its just the first thing that popped up
From healthline:
Is taking high doses of B12 helpful or harmful?
Here is the thing, as with potassium, salt, and many many other things, if your health is compromised, see your doc..But normal healthy folks, let er buck, if you have some desire or need....My last post, i hate google debates, i know and remember shit and LEARN it, i only post as some do not understand etc, so here s some good reading. Im not into i will see your google and raise you a different google search....endless. im out...
Not agitated or being a dick, but ive been doing this shit too long to carry on shit i have debated 20 years ago....and then 12 years ago, then 5 years ago, then last year. Today is not a debate i get that, its good to shre and i learn many times as well, i know very little compared to google, but i know a lot to have a chat out around a campfire with no cell service, thats what matters....to me anyway...its not what one can google, but what one has experienced and absorbed and understands...
Since B12 is a
water-soluble vitamin, it’s generally considered safe, even at high doses.
No Tolerable Upper Intake Level (UL) has been established for B12, due to its low level of toxicity. UL refers to the maximum daily dose of a vitamin unlikely to cause adverse side effects in the general population.
This threshold has not been set for B12 because your body excretes whatever it doesn’t use through your urine.
However, supplementing with excessively high levels of B12 has been linked to some negative side effects.
Several studies have shown that megadoses of the vitamin can lead to outbreaks of acne and rosacea, a skin condition that causes redness and pus-filled bumps on the face.
Yet, it should be noted that most of these studies focused on high dose
injections rather than oral supplements (
5Trusted Source,
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There is also some evidence suggesting that high doses of B12 may lead to negative health outcomes in those with diabetes or kidney disease.
One 2010 study found that people with diabetic nephropathy (loss of kidney function due to diabetes) experienced a more rapid decline in kidney function when supplemented with high dose B vitamins, including 1 mg per day of B12 (
8Trusted Source).