What is TMG (Trimethylglycine)?
Trimethylglycine (TMG), also known as betaine, is a naturally occurring compound found in foods such as beetroot, spinach, quinoa, and wheat germ. It is classified as a methyl donor — a molecule that donates methyl groups (a carbon atom bonded to three hydrogen atoms) to support a wide range of biochemical reactions in the body.
Methylation is one of the most fundamental processes in human biology. It influences gene expression, neurotransmitter production, detoxification, and cardiovascular health. Without adequate methyl donors like TMG, these processes can become impaired.
Key Benefits of TMG
1. Supports Healthy Homocysteine Levels
One of TMG’s most well-researched roles is in the metabolism of homocysteine, an amino acid that, at elevated levels, is associated with increased cardiovascular risk. TMG donates a methyl group to convert homocysteine into methionine, helping to keep homocysteine within a healthy range.
Multiple clinical studies have confirmed that TMG supplementation significantly reduces plasma homocysteine levels, particularly in individuals with genetic variants (such as MTHFR mutations) that impair natural methylation.
2. Liver Health and Fat Metabolism
TMG plays a protective role in liver function. Research shows it helps prevent the accumulation of fat in the liver (hepatic steatosis) by supporting the export of lipids and reducing oxidative stress. It is used clinically in some countries as a treatment for non-alcoholic fatty liver disease (NAFLD).
3. Athletic Performance
Several randomised controlled trials have found that TMG supplementation (typically 2.5 g/day) can improve power output, endurance, and body composition in trained athletes. It is thought to work by supporting creatine synthesis and reducing fatigue-related metabolites.
4. Cellular Methylation and Epigenetic Health
Beyond homocysteine, TMG supports the broader methylation cycle that governs DNA methylation — a key epigenetic mechanism that regulates which genes are expressed. Healthy methylation patterns are associated with slower biological ageing and reduced disease risk.
Why Stack TMG With NMN?
This is where the science gets particularly interesting for longevity enthusiasts.
When you supplement with NMN (Nicotinamide Mononucleotide), your body converts it into NAD+ via the salvage pathway. This process consumes methyl groups — specifically, it generates nicotinamide as a byproduct, which must be methylated and excreted. At higher NMN doses, this can place increased demand on your body’s methyl pool.
If methyl groups become depleted, the downstream effects can include:
- Elevated homocysteine levels
- Impaired DNA methylation
- Reduced neurotransmitter synthesis
TMG replenishes this methyl pool, acting as a buffer that keeps methylation running smoothly even as NMN drives NAD+ production upward. This is why many longevity researchers and clinicians recommend taking TMG alongside NMN — not just for its independent benefits, but to maintain biochemical balance.
Our NMN & TMG Welzo Ultra Purity Supplement Stack is formulated with this synergy in mind, combining ultra-purity NMN with an optimal dose of TMG in a single, convenient stack.
How Much TMG Should You Take?
Typical supplemental doses range from 500 mg to 3 g per day, depending on the goal:
- Methylation support with NMN: 500 mg–1 g/day is generally sufficient
- Homocysteine management: 1.5–3 g/day, ideally under medical supervision
- Athletic performance: 2.5 g/day as used in most sports science trials
TMG is well-tolerated at these doses. The most commonly reported side effect at higher doses is a mild fishy body odour, which is dose-dependent and resolves on reducing intake.
Who Should Consider TMG?
TMG is particularly relevant for:
- Anyone supplementing with NMN at doses of 500 mg/day or above
- Individuals with MTHFR gene variants affecting methylation
- Those with elevated homocysteine on blood tests
- People seeking to support liver health and metabolic function
- Athletes looking for evidence-based performance support
The Bottom Line
TMG is a versatile, well-researched compound that earns its place in a serious longevity stack — both for its independent benefits and its critical role in maintaining methylation balance when taking NMN. If you’re already supplementing with NMN, adding TMG is one of the most evidence-backed refinements you can make.
Explore our NMN & TMG Stack or build your own protocol with our full Longevity Bundle.