Trimethylglycine (TMG)

What is Trimethylglycine (TMG)?

TMG, also called betaine, is a small molecule naturally present in beets, spinach, and whole grains. Your body also makes a small amount of it. It plays a central role in methylation — a behind-the-scenes process that helps regulate everything from DNA activity to mood chemistry. TMG is not the same as betaine HCl, which is a digestive acid supplement; TMG is the anhydrous (non-acidic) form used for methylation and metabolic support.

How does Trimethylglycine (TMG) work?

TMG donates one of its three methyl groups to homocysteine, converting it into the safer amino acid methionine. This directly lowers homocysteine — a compound that builds up when methylation is sluggish and is linked to heart disease and cognitive decline. By keeping methylation running smoothly, TMG also supports the production of SAMe, your body's master methyl donor, which affects mood, liver repair, and inflammation control.

What forms does Trimethylglycine (TMG) come in?

Powder form is the most economical and easy to dose-adjust; it dissolves readily in water or juice. Capsules and tablets are more convenient for on-the-go use. Betaine HCl is a distinct product used for stomach acid support and should not be confused with TMG.

Where it comes from:

Betaine was first isolated from sugar beet molasses in the 19th century — hence the name (from Beta vulgaris, the beet plant). Its role in human metabolism was clarified through the 20th century as researchers mapped the one-carbon methylation cycle. It entered clinical use primarily as a treatment for homocystinuria, a rare genetic disorder causing severe homocysteine buildup, before its broader metabolic benefits gained attention in sports nutrition and preventive cardiology.

What does Trimethylglycine (TMG) help with?

• High homocysteine: TMG directly converts homocysteine into methionine, making it one of the most effective natural tools for bringing elevated homocysteine levels down. This matters because high homocysteine is a well-established risk factor for heart disease and stroke. Even when B vitamin therapy has already been tried, adding TMG can produce additional reductions.
• Heart health and cardiovascular risk: By lowering homocysteine and supporting healthy methylation, TMG helps reduce one of the underlying contributors to arterial damage and cardiovascular risk. Population studies consistently link higher dietary betaine intake with better heart health markers.
• Liver health and fatty liver (NAFLD): TMG is one of the few nutrients that directly supports the liver's ability to process and export fat. It helps prevent fat from accumulating in liver cells, which is the hallmark of non-alcoholic fatty liver disease. It is also used medically in rare cases of severe liver damage.
• Exercise performance and power output: A growing body of research shows that TMG supplementation can modestly improve muscular endurance, strength, and power — particularly in resistance training. The mechanism likely involves better creatine synthesis (creatine production is one of the biggest consumers of methyl groups) and possible effects on hydration at the cellular level.
• Methylation support and MTHFR variants: People with MTHFR gene variants process folate less efficiently, which can slow down the methylation cycle and raise homocysteine. TMG bypasses the MTHFR-dependent pathway entirely, providing an alternative route to keep methylation moving. It is often recommended alongside methylfolate for this group.
• Mood and mental energy: Because methylation is required to make neurotransmitters like serotonin, dopamine, and norepinephrine, supporting it with TMG may help stabilize mood and mental clarity — especially in people whose methylation is impaired. The effect is generally supportive rather than dramatic.
• Insulin sensitivity and blood sugar: Some research suggests TMG may help improve how well cells respond to insulin, which could be beneficial for people with metabolic syndrome or early blood sugar dysregulation. The link appears connected to its role in reducing inflammatory signals and supporting liver fat metabolism.
• Inflammation: TMG has shown modest anti-inflammatory effects in both dietary studies and clinical research, likely connected to its role in methylation and its influence on inflammatory signaling pathways in the liver and gut.

What can Trimethylglycine (TMG) help prevent?

• Cardiovascular events associated with chronically elevated homocysteine (supported by epidemiological and intervention data)
• Liver fat accumulation in people with dietary risk factors for NAFLD

Which foods are rich in Trimethylglycine (TMG)?

1. Beets (beetroot): Beets are the richest known dietary source of betaine/TMG — the compound was literally named after the beet plant. Both fresh beets and beet juice provide meaningful amounts.
2. Quinoa: One of the highest betaine-containing grains, making it a standout choice for plant-based methylation support.
3. Spinach: A reliably good source of dietary betaine, especially when eaten in larger quantities as a salad base or cooked green.
4. Wheat germ and wheat bran: Whole wheat products, particularly the germ and bran portions, contain significant betaine — one reason whole grains consistently outperform refined grains on cardiovascular markers.
5. Shrimp and shellfish: Shellfish, especially shrimp, contain notable amounts of betaine and also provide supporting nutrients like B12 and zinc that work alongside TMG in the methylation cycle.

Practical Tips:

Eating a diet rich in beets, leafy greens, whole grains, and shellfish can provide meaningful dietary betaine. However, supplemental TMG delivers doses (1,000–3,000 mg/day) that are difficult to achieve from food alone, so diet and supplementation are often used together when therapeutic effects are the goal.

What are the side effects of Trimethylglycine (TMG)?

• Fishy body odor (especially at higher doses)
• Nausea or stomach discomfort
• Diarrhea or loose stools
• Mild mood changes or irritability in people who are already good methylators
• Elevated LDL cholesterol reported in some studies at high doses — worth monitoring

Good to know:

TMG is considered safe and well-tolerated at standard doses. The most notable dose-dependent side effect is a fishy body odor caused by its conversion to trimethylamine — this is more common at doses above 3g/day. Starting with a lower dose and splitting it through the day reduces most GI complaints.

How much Trimethylglycine (TMG) should you take?

• Recommended daily: 1,000–3,000 mg per day for most adults. Clinical trials for homocysteine lowering commonly use 2,000–6,000 mg/day in divided doses; sports performance research typically uses 2,500 mg/day. Start at 500–1,000 mg/day and increase gradually.
• Best time of day: Morning or early afternoon; some people find it mildly stimulating, so avoiding it late in the day is sensible.
• With or without food: Best taken with food to reduce the chance of nausea and to align with your body's natural digestive and metabolic rhythms.
• Time to effect: 4–6 weeks for measurable homocysteine reduction; exercise and energy effects may be felt within 1–2 weeks of consistent use.
• How long to take it: TMG can be taken long-term when there is a clear indication (e.g., elevated homocysteine, MTHFR variant). No standard cycling protocol is required, but it's reasonable to recheck homocysteine levels every 3–6 months to assess ongoing need.