Pernicious Anaemia Society
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Methylcobalamin photolysis and side effects?

I almost dread to ask this, but for the people who suffered side effects from methylcobalamin, had the vitamin been exposed to light?

I'm wondering if that is a factor in creating impurities and causing side effects (particularly acne). I'm just not sold on the detox explanation.

Apparently methylcobalamin + air + water = aquocobalamin + formaldehyde. Formaldehyde can cause skin complaints.

I had had no warning to keep the sublingual from light. No mention of it from my doctor and no directions on the jar. It came in a thin white plastic jar. I later tried a methylcobalamin spray in a dark bottle which I kept from light but still had side effects.

I had a similar problem with hydroxocobalamin in a white jar as well. I am testing out a pure liquid form now and keeping it in the dark! So far, so good, but it's early.


At the risk of bringing side effects up yet again :-p, however, they really can be severe for some people and since there are so many conflicting theories as to why they happen, I think it's worth discussing now and then.

17 Replies

It seems that the solid form is much more resistant to photolysis

so it wouldn't worry about the solid stuff.

As for the breakdown products causing side-effects. I would think that the amounts involved are too small. 1000ug of MeCobalamin contains less than 1uMol and will produce less than 1uMol of formaldehyde. That's just 30ug of formaldehyde, which is what you'll consume if you eat one milligram of cauliflower.


Thanks for that response - the formaldehyde issue had been bubbling away in my subconscious for a while after reading about it in an EFSA (European Food Standards Agency) paper on B12 - so good to know what the relative dietary amounts actually are - weren't mentioned in the paper.

Formaldehyde isn't, if I remember the paper correctly a by-product in the decay of hydroxo under sunlight. And, again if I remember correctly, the formaldehyde decay occurs when the methylcobalamin is in solution - ie water is present - not in dry forms.


Thank you for your response:). I was on 5000 mcg methycobalamin and 1000 mcg methylfolate.


well they wont approve assisted dying here but it ok to kill us slowly with renegade supps.make syou wonder what is safe and what not


Glad that you seem to have found something that works for you.

There hasn't really been much if any research into the side-effects of B12 and human biochemistry is so complicated that there are probably huge numbers of factors involved and the explanation for one person may not be the same as the explanation for another - particularly when genetics and other conditions are factored in. Hormonal responses can also throw another spanner in the works

I'm not sure I would quite go with 'detox' as I think it's generally about the fact that B12D lowers your immune system, which means that normal immune system responses like itchiness etc are also lowered. As the immune system gets a boost these responses will be stronger so whilst there may be an element of more poisons being dealt with I think that is compounded by the reaction to the poisons being much stronger and hence more noticeable.

Short of an alergic reaction in the true sense of the word alergic (ie anaphylactic shock) although the side-effects can be very unpleasant they aren't life threatening, unlike a deficiciency. Strictly speaking other reactions are 'sensitivities


So that is why I may feel so bad after my first drop of MethylCobalamin! I had the flu jab the same day and the remains of what may have been a bad cold. Will wait a few more days and then try again! I suspect I may need to build up gradually. I had the doctor's blood test on Friday am and am now trying home supplementation as if I'm going to react / be sensitive I really would prefer to have only one drop in me than a whole injectionful also I may not be quite low enough for the GP to want to treat (here they need a level of below 120 but I'm not sure what the units or reference are for this)


Hope that the results and the GPS reaction go the right way.

When I finally started treating myself and getting the doses I really needed I had a huge cold the week after - but it felt really positive as it was the first time in several years that I'd had a runny nose (another thing that shows immune system is working well) - find the runny nose and sneezing awful and I felt quite grotty on one level but it all seemed so much more positive than what I had become used to - I felt ill and all the signs that I was ill were there as opposed to feeling ill and nothing else pointing to being ill.

As I take most of my B12 nasally I also had pink snot ... but it all washed out quite easily :)


Thanks for your response! I know there could be so many factors behind the side effects, and there's not a ton of research. I think I'm just trying to make peace with what happened to me, and figure out as much as I can. I will probably never quite know!


Crikey...I take 10 to 12 doses of two different B12s a day, including methylcobalamin. Glad I'm slowly switching over to injections! Will need much less taking it that way.


I'm not sure if it's a huge problem, particularly if it's protected from light. I had a TON of side effects and wondered if that was the culprit, I know of other people in a similar situation.


I remember reading somewhere that B12 causes changes in the bacteria on the skin.


Thanks! The worst part is my b12 threshold for not getting acne is too low to help with the nerves. I'm kind of straddling a line.


Not sure whether it was a fluke but my granddaughter had an outbreak of spots after taking her B12 and it cleared up after using a Swiss B12 cream I'd bought her for her eczema ! Homoepathic cure - treat like with like ? !


Interesting..was it a homeopathic b12 cream or an actual b12 containing cream? I did try creams with niacin and zinc, not too much luck..


Not homoepathic, containing B12 - bought through eBay - quite expensive £15.95 - for eczema - as I said, could have been a fluke that it worked on the spots!

Switzerland - Vitacreme B12 Vitamin Regenerative Cream 50ml / 1.76 fl oz.


Thanks! I'll look at it. The acne was so severe, £16 Is cheap when the alternative is permanent scarring. I'm taking tazorac now, which makes my skin red and flaky, but the spots heal without scarring. I appreciate it.


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