I found this on another forum that can be interesting for various forum members having problems with niacin / niacinamide. I hope it helps:
Here is the thread if you want to read more: Does methyl-absorbing niacin neutralise methyl supplements?
Yes I have read Lynch's claims about methyl sponges, along with those that proliferate on the internet offering advice about methylation.
I simply say what is the mechanism?
It is niacinamide that is cleared by methylation via the enzyme NNMT.
If you look at sites detailing niacin and niacinamide metabolism, there is no enzyme listed that methylates niacin.
See for example the entry in KEGG pathways. If you look in the top left hand section you will see niacinamide being converted to N-methyl nicotinamide via the enzyme NNMT, as I described above.
If you look immediately below niacinamide, you will see nicotinate (aka niacin). It is taken in several directions as part of different metabolic pathways and only one which is terminal or a clearance reaction. This is the conversion to nicotinurate.
I didn't canvas this in my previous post because I didn't want to overcomplicate things. This clearance reaction involves the addition of glycine - ie one of the phase II detox pathways which occur predominantly in the liver and which help the body excrete excess or unwanted metabolic products or exogenous substances.
So excess niacin is glycinated, excess niacinamide is methylated.
So I repeat, if Lynch and others claim that niacin is methylated, how does it happen?
I have no doubt the Lynch is knowledgeable about many things and has been helpful to at least some patients, but on this issue he is wrong.
Here is the thread if you want to read more: Does methyl-absorbing niacin neutralise methyl supplements?