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Pernicious Anaemia Society
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Does injecting B12 deplete other vitamins ?

I’ve been SI B12 for more than 12 months. First weekly.....then after trial and error 1 every 2 weeks.

At the start when I was deficient (B12) my GP also gave me 5mg Folic Acid.

After my annual blood test last September I was put on 400ug Folic Acid.....my B12 levels were 3000 but GP didn’t mention anything (He doesn’t know I’m self injecting)....so I think he should have asked why levels are high.

My Vit D was quite borderline but GP didn’t give anything, said is fine so I jbought some as I was having bone pain. I first took a course of 20,000iu 1 tablet twice weekly until they finished (40 in pack). I now bought 1000iu and started taking 2 a day, it’s only been about 10 days and noticed a lot of improvement in my mood(felt much better) was feeling depressed (maybe SAD) but big change, also got much better sleep.

I took it in the evening or night for few days and couldn’t go sleep at all(stayed awake all night), slept during the day until I decided to look up when to take Vit D and it said MORNING !.......never evening or night as it stops the production of melatonin ( the sleeping hormone) which increases at night time naturally. My bone pain I also notice the difference.

Since I’m injecting every 2 weeks what are the chances that this could cause a depletion of other vitamins ???

I’ve been following this site for quite a while and come across (people who inject B12) always mention Magnesium, Potassium, Vitamin B complex, Ferritin and broad spectrum multivitamin.

I didn’t know how bad things can get with low vitamins until I was low on B12 and Vit D and the extent to which Vit D affects your sleep. (So anyone out there taking Vit D DONT take it at night......take it in the MORNING!) it really affects your sleep.

I’m now wondering whether there’s other vitamins/minerals which are being depleted by regular 2 weekly injections since I know the importance of B12, D, Folate (All these make a huge difference together with B12.......so is there anything I should be taking additionally?

I take;

B12 injection every 2 weeks

400ug Folic Acid daily

Vitamin D 2000iu daily

Would it help to take broad spectrum multivitamin (like Wellman) daily ?

.....or a Vit B complex ?......or anything else I should be looking at ?

Additional note;

My diet is not so good (not much fruit or veg), mostly carbs and proteins.

Sorry for the long question.

Thanks in advance.

4 Replies

Long question Ryaan.....I needed a B12 shot to make it to the end !

1 like

Yes - take a daily multivitamin to fill in for the minerals and metals that get depleted when metabolism kicks in after you start on B12 injections

I take my folic acid in 800 mcg tablets- 2x three times a day, 800 x 6 = 4800 mcg (4.8 mg). By spreading it out throughout the day, I feel like I’ve got more energy.



A B12 deficiency is like having an oil leak in your car. You need to top up with oil more frequently. But it doesn't mean that you need to fill up with petrol more often, or that your tyres need pumping up more regularly.


however, just to add, if low when you start getting the B12 you need then the fact that processes weren't running that are now running can cause a temporary depletion of some vitamins - notably B9 and some minerals, because you will be needing more for a while whilst repair work is going on. More significantly, long term is likely to be the fact that the problem that is affecting your ability to absorb B12 may also affect other vitamins and minerals meaning that you may need slightly more than RDA to make sure that you take in enough from your food. However, care is needed in supplementing as it is possible to overdose on many minerals and vitamins and the effect on other vitamins and minerals won't be on the same scale as it is for B12.


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