Trimethylglycine (TMG / Betaine anhydrous)
Trimethylglycine (TMG, also called betaine anhydrous) is an amino-acid derivative present in beetroot, spinach, whole grains, and seafood. It is the principal dietary methyl-group donor for the BHMT pathway, which lowers homocysteine. There is ONE authorised UK health claim — "Betaine contributes to normal homocysteine metabolism" — that requires a daily intake of 1.5 g of betaine to be made on a label.
Camden Medicals editorial · Last reviewed 3 May 2026 · Next review November 2026
- Cross-checked against
- NHS
- NICE
- BNF
- EFSA
- FSA
Camden's editorial team independently graded each health claim below on the strength of the published evidence — see the grade beside every condition.
- Class
- Amino acid
- Typical daily dose
- UK retail TMG products supply 500–2000 mg per serving. The UK-authorised Article 13(1) homocysteine claim requires ≥1.5 g/day from the supplement. Camden NB-161 supplies 600 mg per capsule (1 capsule daily) — below the claim threshold; SKU framing is mechanistic methyl-pool support, not a homocysteine claim.
- Top use evidence
- Moderate
On this page
What it is
Trimethylglycine (TMG), also known as betaine anhydrous or glycine betaine, is an amino-acid derivative — glycine with three methyl groups attached to the nitrogen. It is widely distributed in plant and animal foods. The richest dietary sources are beetroot (~1.5 g per 100 g of red beetroot dry weight), spinach, quinoa, wheat bran, prawns, and other seafood. A typical UK adult diet supplies a few hundred milligrams of betaine per day from food; supplement doses in the homocysteine-metabolism literature are 1.5 g and above.
Biochemically, TMG is a methyl-group donor. In the BHMT (betaine-homocysteine methyltransferase) pathway, TMG donates a methyl group to homocysteine, regenerating methionine and producing dimethylglycine (DMG). This is one of two principal pathways for homocysteine remethylation in the body — the other being the folate/B12-dependent methionine synthase pathway. The two pathways operate in parallel and are tissue-specific (BHMT is expressed predominantly in liver and kidney; methionine synthase is expressed broadly).
UK retail products supply TMG as betaine anhydrous in capsules, tablets, or powder — typically 500–2000 mg per serving. The most-trialled form is unstandardised betaine anhydrous; there are no notable branded "research-grade" preparations for TMG (unlike turmeric or ashwagandha).
Regulatory note: TMG / betaine is on the Great Britain Nutrition and Health Claims Register with one authorised Article 13(1) claim — "Betaine contributes to normal homocysteine metabolism" (Entry Id 4325, Regulation (EU) 432/2012). The register attaches three conditions of use: at least 500 mg of betaine per quantified portion; consumer information that the beneficial effect is obtained with a 1,5 g daily intake; and consumer information that a daily intake above 4 g may significantly increase blood cholesterol. Camden NB-161 supplies 600 mg of TMG per daily serving — it clears the per-portion floor but not the 1,5 g intake at which the effect is stated — so the SKU PDP cannot make the homocysteine-metabolism claim. Mechanistic framing as methyl-pool support paired with NMN is the permissible alternative.
At a glance
- An amino-acid derivative (also called betaine anhydrous) found in beetroot, spinach, whole grains, and seafood. It is a direct methyl-group donor in the body.
- ONE authorised UK food-supplement health claim: "Betaine contributes to normal homocysteine metabolism" (Reg 432/2012, conditional on 1.5 g daily intake from the supplement).
- Conventionally paired with NAD-precursor supplements (NMN, NR) to replenish the methyl groups consumed by NAD-precursor metabolism via NNMT.
- TMG / betaine anhydrous is NOT the same as betaine HCl — the HCl form is used historically for low stomach acid and has different uses and risks.
- Generally well-tolerated. Pregnancy: avoid as a supplement without prescriber review (dietary intake from food is not the concern).
What people use it for
Adults supplementing with NAD-precursors (NMN, NR) — methyl-pool support
NAD-precursor metabolism via NNMT consumes S-adenosyl-methionine (SAM), depleting the methyl pool. TMG is the standard mitigation, donating a methyl group to homocysteine via BHMT. The mechanism is well-described; outcome-trial evidence specifically for the NMN+TMG combination is limited. UK food-supplement claims for "methyl-pool support" or "homocysteine balance" are not authorised; the Article 13(1) claim is on a 1.5 g threshold.
Some evidenceLimitedAdults with documented hyperhomocysteinaemia, alongside NHS pathway management
High-dose betaine (≥1.5 g/day, often 3–6 g) is recognised in clinical literature for lowering elevated homocysteine. Hyperhomocysteinaemia management is a clinical pathway — talk to your GP for assessment of underlying causes (B12 deficiency, folate deficiency, MTHFR genetics, kidney function). Self-supplementation in place of clinical investigation is not appropriate. [4,5]
Some evidenceModerateAdults considering TMG for liver support / fatty liver
Small trials of high-dose betaine (≥1.5 g/day) in non-alcoholic fatty liver disease (NAFLD) have reported some marker improvements. UK NHS / NICE pathways for NAFLD apply (NICE NG49 — non-alcoholic fatty liver disease). TMG / betaine is not on the NICE pathway. UK food-supplement claims for liver support from TMG are not authorised. [2]
Some evidenceLimitedResistance-trained adults exploring supplements for performance
Small trials of betaine 2.5 g/day in resistance-trained men have reported some performance and body-composition endpoints. Trials are small. UK food-supplement claims for athletic performance from betaine are not authorised.
Some evidenceLimitedAdults wanting a dietary methyl-group source, alongside food sources
Beetroot, spinach, and quinoa are the principal dietary sources. TMG / betaine intake from a balanced diet supplies a few hundred milligrams per day, generally well below the supplement threshold. Dietary framing is permissible; specific UK food-supplement health claims below the 1.5 g threshold are not permitted.
Some evidenceLimited
How it works
TMG donates a methyl group to homocysteine via the BHMT enzyme, regenerating methionine. The mechanism is settled biochemistry; in supplement context, it is most often leveraged to replenish the methyl pool depleted by NAD-precursor metabolism (NMN, NR) or to support homocysteine metabolism in folate/B12-pathway-limited individuals.
Common myths
Myth"TMG and betaine HCl are the same thing"
RealityDifferent supplement forms with different uses. TMG / betaine anhydrous is the methyl-donor form used in homocysteine and NAD-precursor context. Betaine HCl is hydrochloric-acid betaine, used historically for low stomach acid and not the form to take for methyl-pool support.
Myth"TMG is a rejuvenation supplement"
RealityUK food-supplement claims for rejuvenation or lifespan-extension are not permitted on TMG / betaine. The supplement context is methyl-pool support for NAD-precursor users and homocysteine metabolism at ≥1.5 g/day; the popular age-reversal framing exceeds the regulator-permissible claim space.
Myth"TMG and folate / B12 do the same thing"
RealityBoth feed into homocysteine remethylation but via different pathways. TMG works via BHMT (predominantly liver and kidney); folate/B12 work via methionine synthase (broadly expressed). They are complementary not interchangeable. People with MTHFR variants, folate deficiency, or B12 deficiency may benefit from addressing the primary pathway first; talk to your GP.
Myth"Higher TMG doses are always better"
RealityThe UK-authorised claim is on 1.5 g/day. Beyond that, marginal returns are small and side effects (GI upset, transient lipid changes at very high doses) rise. Most supplement protocols use 500–2000 mg/day as the working range.
Common online questions
Synthesised from the questions UK shoppers most often ask online about Trimethylglycine (TMG / Betaine anhydrous). Each answer is editorial and links to its evidence in the Sources list below.
What's the difference between TMG and betaine HCl?
TMG (trimethylglycine) is also called betaine anhydrous — it is the methyl-donor form used in homocysteine / methylation context, present in beetroot and other foods. Betaine HCl (betaine hydrochloride) is a different supplement form, used historically as a source of supplemental hydrochloric acid for people with low stomach acid. The two are not interchangeable as products — different uses, different doses, different risk profiles. Camden NB-161 uses TMG / betaine anhydrous, not betaine HCl.
Why is TMG paired with NMN?
NMN is converted to NAD+, then consumed and ultimately cleared back to nicotinamide. The clearance step via nicotinamide N-methyltransferase (NNMT) uses a methyl group from S-adenosyl methionine (SAM). High NAD+ flux therefore depletes the methyl pool. TMG is a direct methyl-group donor that regenerates methionine from homocysteine via BHMT, buffering the methyl pool. The pairing is mechanistic; outcome-trial evidence for the combination as such is limited. Camden NB-161 includes 600 mg of TMG paired with 500 mg of NMN per capsule.
Will TMG lower my homocysteine?
At supplement doses of 1.5 g/day or more, the trial literature supports a reduction in fasting plasma homocysteine — this is the basis of the UK-authorised Article 13(1) claim "Betaine contributes to normal homocysteine metabolism". Below 1.5 g/day, the claim cannot be made and the trial-reported effect is smaller. Diagnosed hyperhomocysteinaemia is a clinical pathway — talk to your GP for assessment of underlying causes (B12 deficiency, folate deficiency, MTHFR genetics, kidney function) before self-supplementing.
Can I take TMG while pregnant?
Talk to your GP first. Dietary intake of betaine from beetroot, spinach, and other foods is not the concern. Standardised TMG supplementation during pregnancy has limited safety data; the conservative position is to avoid supplemental TMG during pregnancy and lactation without prescriber review.
Does TMG raise blood lipids?
Some early trials of high-dose betaine (≥6 g/day) reported transient rises in LDL cholesterol, though the effect was not consistently observed across studies and usually disappeared with discontinuation or dose reduction. At supplement doses of 1.5–3 g/day the signal is small and inconsistent. People with diagnosed cardiovascular disease should disclose TMG use to their prescribing team.
⚖️ The official position
What may lawfully be claimed about Trimethylglycine (TMG / Betaine anhydrous) in Great Britain. This is a regulatory position, not an evidence grade.
A health claim is authorised in Great Britain.
“Betaine contributes to normal homocysteine metabolism”
This claim is authorised for use in Great Britain under the GB Nutrition and Health Claims regulation. A product may carry it when it provides at least 15% of the UK NRV per recommended daily portion.
Authorised UK health claims
Verbatim from the GB Nutrition and Health Claims Register (Reg 432/2012 as assimilated in GB). A product can carry these claims when it provides at least 15% of the UK NRV per recommended daily portion.
1 authorised claim — show / hide
- "Betaine contributes to normal homocysteine metabolism"
🔬 Camden’s evidence review
The research Camden reviewed, graded on its strength. This is our own appraisal — it sits beneath the official guidance above, never above it.
Homocysteine metabolism — high-dose supplementation
ModerateEvidencemoderateTrials of betaine ≥1.5 g/day across 4–12 weeks have reported reductions in fasting plasma homocysteine in healthy adults and in adults with hyperhomocysteinaemia. The effect is settled regulatory science — the UK-authorised Article 13(1) claim "Betaine contributes to normal homocysteine metabolism" (GB NHC register Entry Id 4325, Reg (EU) 432/2012) rests on this evidence base. The register attaches three conditions of use: at least 500 mg of betaine per quantified portion; consumer information that the beneficial effect follows a 1,5 g daily intake; and consumer information that intakes above 4 g/day may significantly increase blood cholesterol. Camden NB-161 supplies 600 mg/day — clearing the per-portion floor but not the 1,5 g intake at which the effect is stated — so the claim is not made on that SKU. [1,5,6]
NAD-precursor methylation buffering — mechanistic
LimitedEvidencelimitedNAD-precursor metabolism via nicotinamide N-methyltransferase (NNMT) consumes S-adenosyl- methionine (SAM), the cell's universal methyl donor. On this widely described biochemistry, sustained NAD-precursor use is reasoned to draw on the methyl pool, and TMG — a direct methyl donor that regenerates methionine via BHMT — is the conventional mitigation. This is the biochemical rationale for TMG inclusion in NMN / NR supplements; outcome-trial evidence for the combination as such is sparse.
Non-alcoholic fatty liver disease (NAFLD) — small trials
LimitedEvidencelimitedSmall trials of high-dose betaine in NAFLD have reported liver-function-marker improvements. UK NICE NG49 lists recognised pathways for NAFLD management; betaine is not on those pathways. UK food-supplement claims for liver support are not authorised. [2]
Resistance-training performance — small trials
LimitedEvidencelimitedSmall trials of betaine 2.5 g/day in resistance-trained men have reported some endpoints in body composition and strength markers. Trials are small. No UK-authorised performance claim.
Safety
TMG / betaine anhydrous is generally well-tolerated in healthy adults at standard supplement doses. Pregnancy: avoid supplemental TMG without prescriber review (dietary intake from food is not the concern). Talk to your prescriber if you take any prescribed medication or have a kidney condition.
Talk to your pharmacist or GP first if you:
- You are pregnant, breastfeeding, or trying to conceive — limited supplement-context safety data.
- You are under 18.
- You have kidney disease — TMG metabolism produces dimethylglycine (DMG) and glycine; clearance pathway considerations.
- You have diagnosed hyperhomocysteinaemia — clinical pathway, not self-supplementation.
- You take any prescribed medication and are unsure of methylation-pathway interactions.
Common side effects: Mild GI complaints (nausea, abdominal discomfort, body odour from DMG metabolism) at higher doses. Generally well-tolerated.
Pregnancy and breastfeeding
Avoid supplemental TMG during pregnancy without prescriber review. Dietary intake of betaine from beetroot, spinach, and other foods is not the concern. Limited supplement-context safety data in pregnancy.
Limited human lactation safety data. Defer to prescriber.
Talk to your GP, midwife, or pharmacist before starting any supplement during pregnancy or breastfeeding.
More clinical detail (for clinicians and informed readers)
Contraindications
- Pregnancy — avoid supplemental TMG without prescriber review (dietary intake from food is not the concern).
- Lactation — limited safety data; defer to prescriber.
- Paediatric use — supplemental TMG not recommended for under-18s.
- Diagnosed kidney disease — relative contraindication; TMG metabolism produces glycine and DMG that are renally cleared.
- TMAU (trimethylaminuria) — relative contraindication; risk of fishy body odour from impaired trimethylamine clearance.
Drug interactions
- Methotrexate — theoretical interaction via folate / methylation pathway; talk to prescriber.
- Levodopa — limited interaction data; possible effect on absorption (theoretical).
- Generally limited interaction profile compared with serotonergic / CYP-modulating supplements.
This is not an exhaustive list. Always tell your prescriber and pharmacist about every supplement you take.
Common side effects
- Mild GI complaints — nausea, abdominal discomfort.
- Body odour — at high doses, the metabolic by-product trimethylamine can produce a fishy odour in some individuals (particularly those with TMAU genetic variants).
Rare side effects
- Allergic reaction.
- Transient rises in LDL cholesterol at very high doses (≥6 g/day) — usually reversible.
How to take it
- Typical supplemental range
- UK retail TMG products supply 500–2000 mg per serving. The UK-authorised Article 13(1) homocysteine claim requires ≥1.5 g/day from the supplement. Camden NB-161 supplies 600 mg per capsule (1 capsule daily) — below the claim threshold; SKU framing is mechanistic methyl-pool support, not a homocysteine claim.
- Timing
- Daily, with food. NMN-pairing protocols typically take both at the same time of day for methyl-pool buffering.
How to spot quality
Look for
- Form declared: betaine anhydrous (= trimethylglycine, TMG). Confirm it is NOT betaine HCl, which is a different supplement form.
- Dose declared per serving (mg of betaine, not just mg of "betaine complex").
- Country of manufacture stated.
- CoA available on request, with batch number and issue date.
- Standardised purity (≥99% by HPLC is the typical commercial bar).
- For the homocysteine-metabolism authorised claim: total daily intake of ≥1.5 g of betaine.
- Pregnancy contraindication on label for supplemental forms.
Red flags
- Confusion of TMG / betaine anhydrous with betaine HCl (different product, different use).
- No declared betaine dose per serving.
- Claim of "homocysteine support" or the Article 13(1) wording on a SKU below 1.5 g/day.
- Marketing as a lifespan-extension or age-reversal supplement (no UK-authorised claim).
- No country-of-manufacture or CoA disclosure.
- Marketed as a clinical hyperhomocysteinaemia therapy (clinical pathway, not self-supplementation).
Where Camden lands · gap declared
TMG is not a standalone Camden SKU. It appears in Camden's catalogue as a co-ingredient in NB-161 (NMN Complex 90 Delayed Release Capsules), which supplies 600 mg of betaine anhydrous (TMG) per 1-capsule serving alongside NMN and the other stack actives. That 600 mg sits below the 1.5 g/day intake the authorised betaine / homocysteine-metabolism claim requires, so no authorised health claim attaches to the TMG component of NB-161 — it is included for its methyl-donor role in the NAD-precursor stack, framed mechanistically rather than as a body-effect claim.
Reformulation or supplier clarification is in progress.
Commonly combined with
Other ingredients that share a biological pathway, cofactor relationship, or evidence-backed protocol with this one. Mechanisms below cite primary physiology — not folk pairing. Doses are literature ranges, not recommendations. Talk to your pharmacist or GP before changing your stack, especially if you take prescription medication.
NMN (β-Nicotinamide Mononucleotide)
Limited evidenceTMG replenishes the methyl groups consumed by NMN metabolism — the standard pairing in NAD⁺-precursor stacks.
Trimethylglycine (TMG, betaine) is a direct methyl-group donor that regenerates methionine from homocysteine via betaine-homocysteine methyltransferase (BHMT), buffering the cellular methyl pool. NAD⁺ precursors (NMN, NR, niacin) increase NAD⁺ flux, which consumes S-adenosyl-methionine (SAM) for nicotinamide methylation by NNMT. Without methyl-pool replenishment, sustained NAD-precursor supplementation can deplete SAM and raise homocysteine in some individuals. TMG co-supplementation is the standard mitigation. The pairing is biochemically well-described; human-trial evidence specifically for the combination remains limited. NMN is on the FSA novel-food register as "pending"; this combination is discussed for mechanistic context, not as a body-effect claim.
Evidence: The methyl-pool buffering rationale for pairing TMG with NAD⁺ precursors rests on well-described biochemistry — NNMT consumes S-adenosyl-methionine when clearing nicotinamide. Combination outcome trials in humans are sparse.
Doses studied: 500–1000 mg TMG with 250–500 mg NMN daily (literature dose range)
Found in Camden: Clarifera™ NMN Complex 90 Delayed Release Capsules
Vitamin B12
Strong evidenceB12 + TMG together complete the homocysteine-remethylation picture (folate/B12 pathway via methionine synthase + TMG/BHMT pathway).
Homocysteine remethylation has two parallel pathways: (1) methionine synthase (B12-dependent), and (2) BHMT (TMG- dependent). Both regenerate methionine from homocysteine. Camden NB-161 supplies both — 150 µg B12 (6,000% NRV) and 600 mg TMG — covering both pathways for users who may have either pathway limitation.
Evidence: Both pathways are settled biochemistry. EFSA-authorised B12 claims include normal homocysteine metabolism. The TMG Article 13(1) claim has the same theme but is conditional on the 1.5 g threshold. [7,8]
Doses studied: B12 100% NRV + TMG 500–2000 mg daily.
Found in Camden: Clarifera™ NMN Complex 90 Delayed Release Capsules