Best Betaine (TMG) Supplement 2026: Top Picks Ranked
Best Betaine (TMG) Supplement 2026: Ranked for Methylation and Performance
Betaine — sold as trimethylglycine (TMG), betaine anhydrous, or simply betaine — is among the most mechanistically well-documented methylation supplements available. It functions as a methyl donor in the betaine-homocysteine methyltransferase (BHMT) pathway, converting homocysteine to methionine. This single function has downstream effects on SAM (S-adenosylmethionine) availability, creatine synthesis, and cardiovascular biomarkers.
In sports nutrition, betaine anhydrous at 2.5 g/day has accumulated a reasonable RCT base for exercise performance, particularly in resistance training. In cardiovascular health contexts, its best-established effect is homocysteine reduction — 12–20% at doses of 1.5–6 g/day (Olthof et al., 2003; PMID: 14652361).
The supplement market conflates two distinct products under the "betaine" label: betaine anhydrous (TMG, for methylation and performance) and betaine HCl (for digestive acid support). Choosing the wrong form is the most common mistake in this category.
This guide covers both forms, the evidence base for each use case, and the top products ranked by dose accuracy, transparency, and value.
How Betaine Works
Methylation and homocysteine metabolism. Betaine (TMG) is a trimethyl compound — it carries three methyl groups, one of which it donates to homocysteine via the enzyme BHMT. This converts homocysteine to methionine. Elevated homocysteine is associated with cardiovascular disease risk; betaine consistently lowers plasma homocysteine in RCTs. The resulting methionine can be converted to SAM (S-adenosylmethionine), the universal methyl donor used in over 200 enzymatic reactions including DNA methylation, neurotransmitter synthesis, and gene expression regulation (Craig, 2004; PMID: 15321791).
Osmolyte function. Betaine is a naturally occurring organic osmolyte — a compound cells use to maintain hydration and volume under osmotic stress. This is particularly relevant during exercise, heat stress, and dehydration. Osmolyte function may contribute to betaine's observed effects on muscle endurance and cell protection.
Creatine synthesis. Methionine (from betaine methylation) contributes to the creatine biosynthesis pathway via guanidinoacetate methylation. This may partly explain why betaine shows performance effects at doses below those typically needed for pure cardiovascular benefits.
Digestive acid support (HCl form only). Betaine HCl dissociates in the stomach, releasing hydrochloric acid. This mechanism is completely separate from methylation and applies only to individuals with hypochlorhydria (low stomach acid). This form is not studied for exercise or homocysteine purposes.
What the Clinical Evidence Shows
Exercise Performance
Lee et al., 2010 (PMID: 19250531): A placebo-controlled crossover trial in active college males found that 14 days of betaine supplementation (1.25 g twice daily = 2.5 g/day) significantly improved squat repetition volume and power output compared to placebo. This is one of the first published RCTs establishing betaine's ergogenic properties.
Cholewa et al., 2013 (PMID: 22080324): A 6-week parallel-group RCT in competitive athletes found betaine (2.5 g/day) increased bench press and squat volume load, improved power output, and reduced markers of muscle damage. Body composition trended positive but did not reach statistical significance at 6 weeks.
Cholewa et al., 2018 (PMID: 30064450): In collegiate females completing a 6-week resistance training program, betaine supplementation reduced fat mass more than placebo but did not significantly increase strength or lean mass. Suggests body composition benefits may occur via non-strength pathways.
Cholewa et al., 2023 (PMID: 37409757): A randomized crossover trial found betaine supplementation improved CrossFit workout performance scores and increased testosterone concentrations. No effect on Wingate peak power (a pure anaerobic sprint measure), suggesting betaine may benefit endurance-strength hybrid activities rather than maximal single efforts.
Summary of performance evidence: Consistent moderate effects on resistance training volume (more reps, more sets), modest body composition benefits, variable effects on pure power/strength. Effect sizes are smaller than creatine. Most useful as a methylation-stack addition rather than a standalone performance enhancer.
Homocysteine and Cardiovascular
Olthof et al., 2003 (PMID: 14652361): Randomized dose-finding trial in healthy adults. Doses of 1.5, 3, and 6 g/day of betaine reduced fasting homocysteine by 12%, 15%, and 20% respectively after 6 weeks — a dose-dependent, statistically significant effect.
Meta-analysis (PMID: 23997720): A meta-analysis of 12 randomized studies confirmed betaine (6 g/day) reliably lowers plasma homocysteine by 5–20% in healthy volunteers.
Important caveat — LDL cholesterol. Olthof et al. (2005; PMID: 15916468) combined data from four RCTs and found betaine supplementation raised LDL cholesterol by approximately 0.2–0.4 mmol/L and increased triglycerides. This lipid-raising effect may offset part of the cardiovascular benefit from homocysteine reduction. Individuals with dyslipidemia should treat this as a material contraindication.
Liver Health
Abdelmalek et al., 2009 (PMID: 19824078): A 55-patient RCT of betaine (20 g/day — far above supplemental doses) in biopsy-confirmed NASH patients found no significant improvement in hepatic steatosis over 12 months. High-dose betaine is not supported as a liver disease treatment based on current evidence.
Jarrow Formulas TMG 500mg — Best Overall
Best for: Daily methylation support, homocysteine management, and building a methylation stack
Jarrow TMG delivers 500 mg betaine anhydrous per tablet — a clean, single-ingredient product from a brand with a long track record of label accuracy and GMP manufacturing standards. There are no proprietary blends, fillers, or unnecessary additives. The tablet form is convenient for daily dosing; for performance-level doses (2.5 g/day), five tablets achieves the clinically studied amount.
Label Analysis
Supplement Facts: Betaine (trimethylglycine) 500 mg per tablet. No proprietary blend. No unnecessary additives beyond basic excipients (microcrystalline cellulose, stearic acid). Non-GMO verified. Jarrow does not carry NSF Certified for Sport or Informed Sport certification on this specific product, which matters for drug-tested athletes.
At 500 mg per tablet, the daily cost for a 2.5 g/day (5-tab) protocol is approximately $0.70–0.90/day — reasonable for a single-ingredient methylation supplement.
Composite Score
| Criterion | Weight | Score | |-----------|--------|-------| | Evidence Quality | 30% | 8/10 | | Ingredient Transparency | 25% | 9/10 | | Value | 20% | 7/10 | | Real-World Performance | 15% | 7/10 | | Third-Party Verification | 10% | 5/10 | | Composite | | 7.6/10 |
Score notes: Scores highly on transparency (pure single ingredient, no blends) and evidence quality (the underlying betaine anhydrous research base is solid). Loses points on third-party verification (no NSF/Informed Sport on this product) and value compared to bulk powder alternatives at performance doses.
Best for: Individuals prioritizing methylation support and convenient tablet dosing at moderate daily amounts (500 mg–1 g/day maintenance). Not the most cost-effective choice if targeting the 2.5 g/day exercise dose.
Bulk Supplements Betaine Anhydrous — Best Value for Performance Dosing
Best for: Athletes and individuals targeting the 2.5 g/day clinically studied exercise performance dose
Bulk Supplements offers pharmaceutical-grade betaine anhydrous powder with certificate-of-analysis testing on every batch. The powder format is the only practical choice for reaching 2.5 g/day without taking 5+ tablets; at 2.5 g per serving, one 100g bag provides approximately 40 servings.
Label Analysis
Pure betaine anhydrous — no additives, no excipients. Lab-tested for identity, heavy metals, and microbial contamination. Unflavored, slightly sweet taste (betaine is naturally sweet). Mixes easily in water or shakes. Certificate of analysis available on request. Not NSF Certified for Sport; not appropriate for WADA-governed athletes without independent testing.
At approximately $0.35–0.55/serving for 2.5 g doses, this is roughly 3–4x more cost-effective than the Jarrow tablets at equivalent performance dosing.
Composite Score
| Criterion | Weight | Score | |-----------|--------|-------| | Evidence Quality | 30% | 8/10 | | Ingredient Transparency | 25% | 9/10 | | Value | 20% | 9/10 | | Real-World Performance | 15% | 7/10 | | Third-Party Verification | 10% | 4/10 | | Composite | | 7.9/10 |
Score notes: Strong value score — hard to beat at this price point per gram. Transparency is excellent (COA-tested, pure ingredient). Third-party verification score is the main weakness; no NSF/Informed Sport on bulk Supplements products.
Best for: Gym-goers, athletes, and anyone targeting the 2.5 g/day performance protocol. Stack with protein shakes — betaine's mild sweetness is unobtrusive.
NOW Foods Betaine HCl 648mg — Best for Digestive Support
Best for: Individuals with hypochlorhydria or poor protein digestion seeking betaine HCl specifically (not for methylation or exercise)
NOW Foods Betaine HCl delivers 648 mg per capsule — one of the cleaner betaine HCl products at its price point. Important caveat: betaine HCl is the wrong form for methylation support or exercise performance. This product's acid-releasing mechanism is entirely different from betaine anhydrous/TMG.
Label Analysis
Supplement Facts: Betaine HCl 648 mg per capsule. No pepsin in this specific formula (some betaine HCl products add pepsin). Non-GMO. GMP quality assurance. Well-priced at $8–14 for 120 capsules.
Composite Score
| Criterion | Weight | Score | |-----------|--------|-------| | Evidence Quality | 30% | 6/10 | | Ingredient Transparency | 25% | 8/10 | | Value | 20% | 9/10 | | Real-World Performance | 15% | 6/10 | | Third-Party Verification | 10% | 5/10 | | Composite | | 6.9/10 |
Score notes: Lower evidence quality score reflects the limited RCT data specifically for betaine HCl in digestive support (most evidence is anecdotal or from older practitioner literature). Value is excellent. Scored separately from betaine anhydrous products because this is a different product with a different use case.
Best for: Digestive acid support ONLY. Do not use this product if your goal is methylation support, homocysteine management, or exercise performance.
Betaine vs. TMG: Clearing Up the Naming Confusion
These terms are synonymous when referring to the anhydrous (pure) form:
- Betaine anhydrous = TMG = Trimethylglycine = same molecule
All three names appear on product labels for the same compound. Choose any of these labels — they refer to the same clinically studied ingredient. The only meaningful distinction is between betaine anhydrous (what you want for methylation/performance) and betaine HCl (for digestive acid support only).
Who Should Use Betaine?
Methylation support seekers: Individuals with elevated homocysteine, MTHFR variants, or those on methylation protocols who want to support the BHMT pathway alongside methylfolate and B12. Effective at 1.5–6 g/day.
Resistance-trained athletes: Individuals performing progressive overload training who want a research-backed add-on beyond creatine. The evidence base supports modest volume and endurance improvements at 2.5 g/day. Works best over 4–8 weeks.
Hybrid performance athletes: CrossFit, OCR, and endurance-strength hybrid athletes may get more benefit than pure powerlifters based on the Cholewa et al. (2023; PMID: 37409757) CrossFit data.
Who should avoid or proceed with caution: Individuals with high LDL cholesterol, elevated triglycerides, or existing cardiovascular risk — betaine raises blood lipids (PMID: 15916468). WADA-governed drug-tested athletes should seek NSF Certified for Sport-certified products; neither pick above carries that certification.
Final Verdict
For exercise performance at the clinically studied 2.5 g/day dose, Bulk Supplements Betaine Anhydrous offers the best value and the correct form. For daily methylation support at lower doses with convenient tablet format, Jarrow TMG 500mg is a clean, reliable choice. The NOW Foods Betaine HCl belongs in a separate category — appropriate only for digestive acid support, not methylation or exercise.
Betaine is a useful but not transformative supplement. Its evidence base is real and consistent, but effect sizes for exercise performance are modest. The strongest evidence is for homocysteine reduction (well-established), followed by resistance training volume (consistent across multiple RCTs), followed by body composition (suggestive but less consistent).
The lipid-raising effect is genuine and should factor into decision-making for anyone with cardiovascular concerns.
Frequently Asked Questions
What is the best betaine supplement for exercise?
For the clinically studied performance dose (2.5 g/day), betaine anhydrous powder is the most cost-effective choice — tablet-based products would require 4–5 tablets to reach this dose. Bulk Supplements betaine anhydrous provides laboratory-tested powder at approximately $0.35–0.55 per 2.5 g serving.
Is TMG the same as betaine?
Yes. TMG (trimethylglycine) is the chemical name for betaine anhydrous. You will see the compound labeled as "TMG," "betaine anhydrous," or "trimethylglycine" on different products — they are identical. Betaine HCl is a different compound; confirm the label says "anhydrous" or "TMG" if your goal is methylation or exercise support.
Does betaine actually work for building muscle?
The evidence suggests modest benefits for training volume (more total reps and sets) rather than direct muscle building. Cholewa et al. (2013; PMID: 22080324) and Lee et al. (2010; PMID: 19250531) found improved repetition volume and power output, but lean mass increases were inconsistent across studies. Betaine is not in the same tier as creatine for hypertrophy evidence.
What is the dose of betaine for homocysteine?
Doses from 1.5 to 6 g/day have been studied for homocysteine lowering. A 12% reduction was seen at 1.5 g/day; up to 20% at 6 g/day (Olthof et al., 2003; PMID: 14652361). Most practitioners use 2–3 g/day as a practical starting dose.
Can betaine be taken with creatine?
Yes. There is no known interaction between betaine and creatine, and some formulations combine both. Betaine may support creatine synthesis via the methionine pathway, so there is theoretical complementarity, though combined RCTs are limited.