TMG (Trimethylglycine): What It Does, Why It Works, and How to Take It
Most people find TMG through NMN. They're researching NAD+ precursors, land on a protocol, and suddenly they're reading about methylation. It doesn't have to be complicated.
Here's what you need to know.
What Is TMG?
TMG stands for trimethylglycine. It's a naturally occurring compound found in beetroot and other plant foods, studied in clinical research for decades. The name tells you what it does: three methyl groups attached to glycine, an amino acid.
Those methyl groups are the point. TMG is one of the body's primary methyl donors, feeding the reactions that keep the methylation cycle running.
What is TMG? A plain-English explanation →
How Methylation Works and Why It Matters
Methylation regulates gene expression, neurotransmitter synthesis, detoxification, and cardiovascular health. When it runs efficiently, your body produces SAMe (S-adenosylmethionine), the universal methyl donor that keeps these processes moving.
When it doesn't, homocysteine builds up. That's an inflammatory amino acid linked to cardiovascular disease, cognitive decline, and impaired mitochondrial function.
TMG remethylates homocysteine back into methionine, which keeps homocysteine in check and the methylation cycle moving.
TMG and methylation: what the research says →
Why TMG and NMN Are Almost Always Taken Together
NMN raises NAD+ levels. That reaction consumes methyl groups. Over time, sustained NMN supplementation can deplete methylation capacity, especially if your baseline is already under pressure from stress, alcohol, or MTHFR gene variants.
TMG replenishes that methyl supply. It keeps methylation running while NAD+ levels rise. This is why TMG appears in NMN protocols almost universally, and why NMN Bio includes TMG in the Morning Bundle.
This is not a marketing pairing. It's a biochemical one.
TMG and NMN: the longevity pairing → TMG dosage with NMN →
TMG Benefits: What the Research Shows
Cardiovascular support
TMG's most studied application is homocysteine reduction. Elevated homocysteine is an independent risk factor for cardiovascular disease. Clinical trials have shown TMG significantly reduces plasma homocysteine at doses of 500mg to 6g per day.
TMG and blood pressure: what the evidence says →
Liver function
TMG was originally used clinically to treat non-alcoholic fatty liver disease. It supports fat metabolism in the liver and protects against liver cell damage. The mechanism: TMG donates methyl groups to produce phosphatidylcholine, a key component of cell membranes and liver fat transport.
Methylation support for MTHFR variants
Around 40% of the population carries a variant of the MTHFR gene that reduces methylation efficiency. TMG activates an alternative pathway (betaine-homocysteine methyltransferase, or BHMT) that works independently of MTHFR. That makes it directly relevant for people who carry this variant.
Athletic performance
Betaine, the other name for TMG, has real evidence behind it in sports performance research. Studies in trained athletes show improved power output and endurance at doses of 2.5g per day, via cellular hydration, creatine synthesis, and mitochondrial efficiency.
TMG Dosage: How Much to Take
The research-backed range is 500mg to 6g per day, depending on the goal.
For general methylation support alongside NMN: 500mg to 1g per day is the standard starting point.
For homocysteine management: clinical trials have used 1.5g to 3g per day.
For athletic performance: 2.5g per day is the most studied dose.
NMN Bio TMG capsules deliver 500mg per capsule. Most people start with one and assess from there.
Best Time to Take TMG
Take TMG in the morning with your NMN. Both absorb well with food. A single morning dose with breakfast is the standard approach.
Higher-dose protocols sometimes split the dose, half in the morning and half at midday. For most people taking TMG alongside NMN, that's not necessary.
Best time to take TMG: the complete timing guide →
TMG Side Effects
TMG is well tolerated in the published research. At higher doses, some people notice a fishy body odour (a by-product of trimethylamine production, more common above 3g per day) or mild gastrointestinal discomfort.
At 500mg to 1g, the range most NMN users will take, side effects are uncommon.
TMG side effects: full breakdown →
TMG in Food vs Supplement Form
TMG occurs naturally in beetroot, spinach, quinoa, wheat germ, and shellfish. Beetroot is the richest source at around 300mg per 100g. Getting a therapeutic dose from food alone means eating substantial amounts consistently.
Supplementation is more practical for reliable dosing, especially when the goal is supporting NAD+ metabolism.
The NMN Bio TMG Formula
NMN Bio TMG delivers 500mg of pharmaceutical-grade trimethylglycine per capsule, 90 capsules per bottle. No fillers, no proprietary blends, no undisclosed amounts.
It's also in the Morning Bundle alongside NMN 500 and NAD+ Brain, the full morning NAD+ protocol in one.
Shop TMG 500mg → Shop Morning Bundle →
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