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CBS a360 - reason to stop MTHFR supplements ?

Homozygous on CBS a360

Is this enough to warrant stopping methyl-B12 and methyl-folate in order to treat CBS fist?

Yasko sort of freaked me out after I just read her book.



Senior Member
Arizona, USA
I can give you an opinion: no, it's not. My opinion is that you need symptoms or test results to determine if you have sulfur (or ammonia) problems. If you are already on methylation supplements and doing well, I see no reason to stop. Please note that this is just an opinion. There are other threads about Yasko's take on CBS, what the research really says, etc. that you can find on this site. I suggest you take a look and come to your own conclusions.


Senior Member
As long as you're tolerating the methyl supplements, and don't have problems with sulfur foods, meds or supps, CBS is probably not expressed. The reason to treat CBS is if you're not tolerating methyl supplements - i.e. getting a stress/anxiety reaction, or head pressure, etc. - so that you can't proceed with the methylation protocol.

In addition, A360A is the minor CBS SNP, and I haven't noticed too many people with that SNP having a problem with CBS.

So it sounds like you're probably ok to continue with the methyl supps.


Juice Me Up, Scotty!!!
Murcia, Spain
People say that CBS often gets expressed when you start with methylsupplements. Taurine and sulfate in urine should tell you. And not tolerating the supplements of course. I have the worst CBS mutation homozigous and my taurine in urine is actually defficient, the lowest aminoacid in my urine aminoacid testing.

By the way, this is sargonnas!
I'm homozygous for CBS a360 as well and have been wondering the same thing! And the information from yasko et al regarding B6 supplementation seems to be all over the place. Very confusing.


I'm having a hard time increasing hydroxy b12 dosage. Help!

I'm "only" heterozygous CBSA360A, but sulfate strips were over 1000 a few months ago. I've AHCY+-, too, but that didn't seem to mitigate CBS here. So after a couple months of limiting thiol/sulfur foods, sulfate strips are down to 400. Yippee! But I can't bump hydroxy b12 up over 250mcg. Insomnia kicks in. I cannot afford that. This has been going on for a couple weeks. Give it more time? I'm BHMT+- also, which mimics CBS, so was thinking about adding phosphatidlyserine stuff (PS/PC/PE), but not sure if I need to now that sulfate seems lower.

I'm homo MTR/MTRR so really want to get some B12 going somehow. Want to get on full SMP eventually.

Btw, I erroneously tried 1g methyl b12 a month ago (dr's advice) and I felt crazy hyped (prob overmethylated) the next day. So I think COMT may be in play -- even tho I'm "only" hetero V158M/H62H. Was hoping VDR Taq++ would mitigate that, but based on mB12 reaction, that doesn't seem to be the case.

I wonder if something else could be getting in the way of B12 for me. A great naturopath cleared out mercury 10 yrs ago. And my current acupuncturist (also very good) isn't picking up bacteria or metal toxins.

Ideas? Thx for any help. Brain fog kicking in.