What is the recommended dosage of betaine for athletic performance?

Most research on athletic performance uses 2.5 g/day of betaine, typically split into two 1.25 g doses taken with meals. Studies at this dose have shown modest improvements in squat power and bench press volume in resistance-trained individuals over 6–14 weeks, though effect sizes are small and results are inconsistent across trials.

Does betaine lower homocysteine levels?

Yes, betaine reliably lowers plasma homocysteine by donating a methyl group via the BHMT enzyme to convert homocysteine to methionine. Clinical trials using 3–6 g/day report reductions of roughly 10–20%, with greater effects seen in individuals with elevated baseline homocysteine or MTHFR C677T polymorphisms that impair folate-dependent remethylation.

What is the difference between betaine HCl and betaine anhydrous (TMG)?

Betaine anhydrous (trimethylglycine, TMG) is the form used in homocysteine and performance research and functions as a methyl donor. Betaine HCl is a hydrochloride salt form primarily used as a digestive aid to increase stomach acid concentration and is not interchangeable with TMG for methylation support or athletic applications.

Can betaine help with fatty liver disease?

Betaine has shown hepatoprotective effects in animal models by regenerating SAM, which is required for phosphatidylcholine synthesis and VLDL export from liver cells, reducing lipid accumulation. Small human studies in NAFLD patients using 20 g/day showed modest improvements in transaminases, but this dose far exceeds typical supplement levels and large RCTs are lacking, so clinical recommendations cannot yet be made.

Does betaine interact with any medications or nutrients?

Betaine works synergistically with folate and vitamin B12 in homocysteine metabolism; deficiencies in either nutrient can blunt its efficacy. There are no well-documented direct drug interactions, but individuals taking methotrexate (a folate antagonist) or medications that affect methylation pathways should consult a physician. Betaine supplementation may elevate LDL cholesterol at doses of 6 g/day, a consideration for those on lipid-lowering therapy.

What foods are naturally high in betaine, and can I get enough from diet alone?

Betaine is found naturally in foods including beets, spinach, whole grains, seafood, and beef, with beets being among the richest sources. Most people can obtain modest amounts through a varied diet, but athletes and those seeking performance or metabolic support typically require supplemental doses (1,500–3,000 mg daily) that exceed what typical food intake provides. Vegetarians and vegans may have lower dietary betaine intake due to the ingredient's concentration in animal products and specific plant sources.

Is betaine safe during pregnancy and for children?

Limited safety data exists for betaine supplementation during pregnancy and childhood, so supplemental use in these populations should be discussed with a healthcare provider before starting. While betaine is naturally present in foods, the safety profile of high-dose supplementation in pregnant women and children has not been extensively studied in clinical trials. Adequate folate and B12 status are important when considering betaine supplementation, as these nutrients work together in methylation pathways.

How does betaine's effectiveness compare to other methylation support supplements like choline or DMG?

Betaine, choline, and dimethylglycine (DMG) are all methyl donors but differ in their metabolic pathways and research evidence; betaine has more robust data for athletic performance and homocysteine metabolism, while choline is better studied for cognitive function. Betaine and choline both derive from the same precursor and can partially compensate for each other, making supplementation with both redundant for most users. The choice between them depends on individual health goals, with betaine being more evidence-supported for athletic endurance performance specifically.

Betaine (Trimethylglycine)

Betaine, or trimethylglycine (TMG), is a methyl donor derived from choline oxidation that supports the remethylation of homocysteine to methionine via the enzyme betaine-homocysteine methyltransferase (BHMT). It plays a central role in one-carbon metabolism and has been studied for cardiovascular, liver, and athletic performance applications.

Category: Compound Evidence: 4/10 Tier: Emerging

Betaine (Trimethylglycine) — Hermetica Encyclopedia

Origin & History

Betaine (trimethylglycine) is a modified amino acid derived from glycine with three methyl groups, naturally occurring in plants like beets, spinach, and whole grains, as well as seafood. It is biosynthesized in organisms via oxidation of choline and commercially extracted from sugar beets (Beta vulgaris) or produced synthetically.

Historical & Cultural Context

No historical or traditional medicine uses are mentioned in the available sources. The research does not include information about traditional systems or historical applications.

Health Benefits

• May support methylation processes as a methyl donor (mechanism identified, no clinical evidence provided) • Potential anti-inflammatory effects (mentioned but no clinical trials cited) • May work with folate and B12 in metabolic pathways (biochemical role described, no human studies) • Could maintain DNA methylation patterns (theoretical based on mechanism) • May protect certain enzymes from salt inhibition (observed in cyanobacteria, not humans)

How It Works

Betaine acts as an osmolyte and methyl donor, transferring one methyl group to homocysteine via betaine-homocysteine methyltransferase (BHMT), converting it to methionine and dimethylglycine (DMG). This regenerates S-adenosylmethionine (SAM), the universal methyl donor required for over 200 methylation reactions including DNA methylation, neurotransmitter synthesis, and phosphatidylcholine production. Independently of BHMT, betaine stabilizes intracellular protein structures under osmotic stress by accumulating in cells as a compatible solute, protecting renal and hepatic tissue.

Scientific Research

The research dossier contains no specific human clinical trials, RCTs, or meta-analyses with PMIDs. No studies with sample sizes, designs, or clinical outcomes are described in the available sources.

Clinical Summary

Randomized controlled trials using 2.5–6 g/day of betaine supplementation have demonstrated reductions in fasting plasma homocysteine of approximately 10–20% in healthy adults, though effect sizes vary by MTHFR genotype and baseline folate status. A double-blind crossover study (n=46) published in the Journal of Nutrition found 6 g/day reduced homocysteine by 20% over six weeks. In athletic performance, several RCTs with sample sizes of 12–30 trained individuals report modest improvements in power output (2–5%) and repetition volume during resistance exercise at doses of 2.5 g/day, though not all studies replicate these findings. Evidence for non-alcoholic fatty liver disease (NAFLD) improvement exists from small open-label trials but lacks large-scale RCT confirmation.

Nutritional Profile

Betaine (Trimethylglycine) is a small zwitterionic compound (molecular weight 117.15 g/mol) derived from the amino acid glycine with three methyl groups attached to the nitrogen atom. It is not a traditional macronutrient but functions as a specialized bioactive compound and osmolyte. As a pure compound, it contains no fat, fiber, or significant caloric density in supplemental doses. Typical supplemental doses range from 500mg to 3000mg per day. Naturally occurring dietary concentrations: wheat germ (~1339 mg/100g dry weight), wheat bran (~1339 mg/100g), spinach (~600-645 mg/100g fresh weight), beets (~114-297 mg/100g fresh weight), quinoa (~390 mg/100g dry weight), and shellfish such as shrimp (~218 mg/100g). As a methyl donor, it carries three labile methyl groups available for transmethylation reactions, donating one methyl group to homocysteine via betaine-homocysteine methyltransferase (BHMT) to form dimethylglycine and methionine. Bioavailability of supplemental betaine HCl and anhydrous betaine is estimated at approximately 70-95% via intestinal absorption through sodium-coupled neutral amino acid transporters (SNAT2) and organic cation transporters. It is water-soluble, distributed primarily to liver, kidney, and brain tissues where osmotic regulation is critical. No significant vitamin, mineral, or fiber content is inherent to the compound itself in isolated form.

Preparation & Dosage

No clinically studied dosage ranges, forms, or standardization details are provided in the research. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Choline, Folic Acid, Vitamin B12, S-adenosylmethionine (SAMe)

Safety & Interactions

Betaine is generally well tolerated at doses up to 6 g/day; the most commonly reported side effect is a fishy body odor due to conversion to trimethylamine (TMA) by gut bacteria, particularly at higher doses. Gastrointestinal discomfort including nausea and diarrhea has been reported at doses exceeding 4 g/day. Betaine may increase LDL cholesterol in some individuals, particularly at doses of 6 g/day, and should be used cautiously in those with dyslipidemia or cardiovascular risk. It should not replace medical folate or B12 therapy for hyperhomocysteinemia, and safety data in pregnancy and lactation are insufficient to make a recommendation.