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TMG (Trimethylglycine / Betaine Anhydrous)
A methyl donor (betaine) that reliably lowers homocysteine and modestly aids strength/power and endurance — but can raise LDL cholesterol, and doesn't improve body composition.
What the evidence says
Most TMG studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2017–2025 with a typical study size of 21 participants.
Based on 7 studies · 4 meta-analyses · 1 RCT · 21 total participants
Confidence
HighBy outcome
TMG has an evidence score of 5.8/10 — moderate evidence based on 7 indexed studies, including 4 meta-analyses. A methyl donor (betaine) that reliably lowers homocysteine and modestly aids strength/power and endurance — but can raise LDL cholesterol, and doesn't improve body composition. Representative study: PMID 39514262.
The commonly studied dose of TMG is 2.5-6g betaine/TMG daily (performance studies commonly use ~2.5g; methylation/homocysteine use up to 6g). Individual needs vary — start at the lower end of the range and adjust based on how you respond.
See full supplement plans that include TMG.
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Last reviewed June 2026 · evidence from 7 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
TMG (trimethylglycine), also called betaine anhydrous, is a methyl donor and cellular osmolyte. It reliably lowers homocysteine (by remethylating it to methionine) and is used as a performance aid: meta-analyses show modest improvements in strength/power and some endurance measures, likely via cellular hydration and methylation support. Two honest caveats from the evidence: it does NOT improve body composition, and it can moderately raise total/LDL cholesterol — a real cardiovascular trade-off at higher doses. (Distinct from betaine HCl, which is used for stomach acid, not methylation.)
Donates methyl groups to remethylate homocysteine to methionine, supporting methylation and lowering homocysteine.
Acts as an osmolyte that supports cell hydration and may aid muscular performance.
Methylation support contributes to endogenous creatine production.
How TMG works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
2.5-6g betaine/TMG daily (performance studies commonly use ~2.5g; methylation/homocysteine use up to 6g)
Take with food
| Form | Type |
|---|---|
| 💊Betaine anhydrous (TMG) | Recommended |
| 🧪Powder | Alternative |
| 💊Capsule | Alternative |
Distinct from betaine HCl (stomach acid).
Minimum: 2 weeks
Optimal: 8 weeks
Cycling: Not required
Note: With meals; can dose pre-workout for performance.
Dose-response data unavailable. The current published research for TMG does not provide sufficient dose-specific outcome data to generate reliable dose-response curves.
Refer to the Dosage & Timing section above for recommended dose ranges based on available evidence.
Modest gains in strength and power output.
Reliably lowers homocysteine.
Can moderately increase total and LDL cholesterol.
Does not meaningfully change body fat or lean mass.
Monitor lipids — betaine can raise LDL.
Food amounts fine; supplemental doses not well studied.
Few documented drug interactions; monitor lipids if at cardiovascular risk.
Tip: Monitor lipids; lower dose; pair with lipid-aware diet
Tip: Reduce dose
The best time to take TMG is with meals. Taking it with food is preferred. Taken with meals; performance protocols often split or dose pre-workout.
TMG is generally safe at recommended doses, with a few precautions worth noting. The most commonly reported side effects are raised LDL/total cholesterol, GI upset/fishy body odor (high doses). Use caution if any of these apply to you: High cardiovascular risk / elevated LDL (may raise cholesterol); Kidney disease (use caution).
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