What is TMG (Trimethylglycine)?
TMG, short for trimethylglycine and also known as betaine, is a compound that donates methyl groups to support the body's methylation reactions. It is taken as a supplement to help keep the methylation cycle running, often alongside NAD+ precursors.
It sits within the methyl economy, the network of molecules that pass small methyl tags between one another. TMG is valued because it can hand over a methyl group to support methylation, which is why it is often paired with NMN, since raising NAD+ can draw on the same methyl supply. In that role it overlaps with methylated B vitamins, which support the cycle from a different angle.
It appeals to people taking NAD+ precursors who want to replace methyl groups those supplements may consume, and to anyone supporting methylation more generally. The catch is that not everyone needs extra methyl donors, and adding TMG when the cycle is already balanced can tip some people towards feeling restless or on edge. For that reason the dose is best matched to a real need rather than taken as a routine add-on.
If you are taking a methyl-demanding precursor and want the matching source, see our NMN.
Frequently asked questions
How is it different from methylated B vitamins?
TMG donates a methyl group directly to the cycle, while methylated B vitamins supply folate and B12 in an active form that the cycle uses as cofactors. One hands over the tag, the others keep the machinery that moves tags supplied.
Who uses it, or when is it the right choice?
It is commonly taken by people using NMN or similar precursors to offset the methyl groups those may use up. It also suits anyone advised to support methylation who tolerates methyl donors well.
When is it the WRONG choice?
It is the wrong choice for people who feel wired or anxious on methyl donors, since it can add to that. It is also unnecessary for someone whose methylation is already well supported by diet.