What it is: Trimethylglycine (TMG), also called betaine, is a compound naturally found in beets, spinach, and whole grains.
How it works: TMG is a methyl donor, providing CH3 methyl groups that are essential for hundreds of biochemical reactions in your body, including the conversion of NMN to NAD+.
The science: Here's the key point most people miss: when NMN is converted to NAD+, and when NAD+ is used and recycled, these processes consume methyl groups. Without sufficient methylation capacity, your body can't efficiently process NMN or maintain the NAD+ cycle.
TMG provides methyl groups through the betaine homocysteine methyltransferase (BHMT) pathway, which converts homocysteine back to methionine. Methionine then produces S-adenosylmethionine (SAMe), the body's universal methyl donor.
This pathway is particularly important because it's independent of folate and vitamin B12, meaning it works even if you have genetic variations (like MTHFR mutations) that affect other methylation pathways.
Why it matters: Methylation is involved in:
- DNA synthesis and repair
- Gene expression regulation
- Neurotransmitter production
- Detoxification
- NAD+ metabolism
Without adequate methyl donors, taking high doses of NMN could theoretically deplete your methyl pool, potentially increasing homocysteine levels (a cardiovascular risk factor).
Synergy with NMN: TMG ensures that your body has the biochemical resources it needs to efficiently convert NMN to NAD+ and maintain healthy methylation throughout the NAD+ cycle. Think of it as providing the raw materials needed for the factory to run smoothly.