Last reviewed: May 2026 · Reviewed by: Harley Medic Editorial Team · Category: Methylation, Longevity & Performance Supplements
If you’re searching for the best TMG supplement in the UK in 2026, this doctor-led, best reviewed TMG comparison ranks every credible UK product against eight clinical criteria — and explains why dose, form, and methyl-donor pairing with NMN matter more than marketing claims. Note: replace this placeholder with a relevant Harley Medic internal link → [link to Harley Medic methylation hub or longevity category].
Quick verdict: the best TMG supplement UK 2026
After comparing every credible UK TMG supplement against eight clinical criteria — dose, source form, purity, manufacturing standard, third-party testing, format, ingredient transparency, and cost-per-effective-dose — Welzo Ultra Purity TMG (£16.99, down from £24.99 RRP) is our best TMG supplement pick of 2026. It delivers a clinically meaningful 1000mg of pure TMG (Betaine Anhydrous) per serving in a single-ingredient capsule — no fillers, no binders, no synthetic additives — manufactured in the UK to GMP standards and third-party tested for purity. As a best reviewed TMG product, it pairs cleanly with NMN, NR, and other longevity supplements as a standard methyl donor companion.
Why TMG matters: the science behind UK TMG supplements
Trimethylglycine — better known as TMG or betaine anhydrous — is one of the body’s primary methyl donors. It’s a naturally occurring compound found in beetroot, spinach, quinoa, and wheat bran, structurally a glycine molecule with three attached methyl groups. Those three methyl groups are the entire point: TMG donates them to power methylation reactions across DNA, neurotransmitter synthesis, liver detoxification, phospholipid production, and homocysteine clearance — billions of times per second across every cell in your body.
TMG has become the standard methyl donor companion in modern longevity protocols (most notably alongside NMN and NR) because NAD⁺ metabolism consumes methyl groups; replenishing them with TMG is a strategy popularised by Dr David Sinclair and now baked into virtually every evidence-informed longevity stack.
What TMG does in the body
Three mechanisms make TMG clinically interesting and explain why it ranks so consistently across “best TMG supplement” reviews:
- It’s a methyl donor via the BHMT enzyme. TMG donates a methyl group through the betaine-homocysteine methyltransferase (BHMT) enzyme, converting homocysteine back to methionine. Crucially, this is a folate- and B12-independent methylation pathway — particularly relevant for individuals with MTHFR gene variants who have impaired folate-based methylation. In the liver, BHMT catalyses up to 50% of homocysteine metabolism.
- It’s an osmolyte. TMG helps regulate the balance of water and salt inside cells, maintaining a stable cellular environment. This is the basis for some of the athletic performance evidence — improved cellular hydration may support training volume and power output.
- It supports SAM (S-adenosylmethionine) regeneration. SAM is the universal methyl donor in human biochemistry; nearly every methylation reaction draws on it. By feeding methionine back into the cycle, TMG helps maintain SAM availability — which becomes important when methylation demand is high (such as during high-dose NMN supplementation).
What the human evidence actually shows
| Study (Year) | Population | Dose | Key finding |
|---|---|---|---|
| McRae (2013) — meta-analysis | 5 RCTs, 206 healthy adults | 4–6 g/day, 6–24 weeks | Plasma homocysteine ↓ 1.23 µmol/L (~11.8% from baseline) — statistically significant |
| Olthof et al. (2005) | 151 healthy adults, 4 RCTs pooled | ~6 g/day | Lowered homocysteine but raised LDL cholesterol and triglycerides — important caveat for high-dose use |
| Cholewa et al. (2014) — review | Resistance-trained adults | ~2.5 g/day | Modest improvements in repetitions, training volume, and power output |
| Ashtary-Larky et al. (2021) — meta-analysis | Pooled RCTs | Variable | Confirmed homocysteine reduction; flagged total cholesterol increase at ≥4 g/day for ≥6 weeks |
| Schwab et al. (2002) | Healthy volunteers | 6 g/day for 12 weeks | Significant homocysteine reduction; one of the foundational human RCTs |
The pattern across this evidence base: TMG reliably lowers homocysteine at 4–6 g/day, supports modest athletic performance benefits at ~2.5 g/day, and is well-tolerated short-term. The cholesterol caveat at high doses is real and worth knowing — for most longevity-focused users at 1–2 g/day, this is unlikely to be an issue, but anyone considering 4 g+/day should monitor their lipid panel.
Important context: TMG is sold in the UK as a food supplement. It is not a licensed medicine and is not approved to prevent, treat, or cure any disease, including cardiovascular disease. The published evidence supports it as a well-tolerated methylation adjunct, particularly valuable when NAD⁺ precursor supplementation increases methyl group demand.
How we ranked the best TMG supplements UK buyers can purchase in 2026
The UK TMG supplement category has expanded significantly since 2022, driven by demand from longevity protocol users pairing NMN with methyl donors. Quality varies by 5×+ between products. Our framework for ranking the best TMG supplements UK shoppers should consider prioritises the eight variables that actually determine whether a TMG supplement will deliver the methylation benefits seen in published research:
- Dose adequacy. Effective protocols range from 500 mg/day (basic methylation support) through 1000 mg/day (NMN methyl-donor pairing) to 4–6 g/day (homocysteine reduction in clinical trials). Products should make their per-serving dose clearly visible.
- Source form. “TMG” and “betaine anhydrous” are the same compound; either name is acceptable. Avoid betaine HCl, which is a different compound (a digestive aid for stomach acid). The best reviewed TMG products use anhydrous betaine, the methylation form.
- Purity and ingredient transparency. Single-ingredient products are easier to evaluate. Stacked formulas with B12, folate, or B6 can be useful but should disclose every dose.
- Third-party testing. Reputable products publish Certificates of Analysis verifying TMG content and screening for heavy metals.
- Manufacturing standard. GMP-certified facilities, batch consistency, traceable supply chain.
- Format flexibility. Capsules suit fixed-dose users; powders allow flexible dosing across the 500 mg–6 g range; liquid vcaps suit users with swallowing difficulties.
- Cost-per-effective-dose. Daily TMG protocols typically run 3–12 months. Sustainable cost matters.
- UK availability and traceability. Reputable UK retailers, verified manufacturer sourcing, proper customs/regulatory compliance.
We deliberately do not rank by social-media popularity or marketing claims. The best TMG supplements UK 2026 are ranked by what matters clinically.
Comparison table: the best TMG supplements UK 2026
| # | Product | Dose per serving | Format | Best for | Price |
|---|---|---|---|---|---|
| 1 | Welzo Ultra Purity TMG (Editor’s pick) | 1000 mg | Capsule (2/day) | Most adults pairing TMG with NMN/NR longevity stack | £16.99 |
| 2 | NOW Foods TMG 1000mg | 1000 mg | Tablet (100/bottle) | Single-tablet 1000mg dose, NOW brand loyalists | £18.44 |
| 3 | Life Extension TMG 500mg Capsules | 500 mg | Capsule (60/bottle) | Lower-dose entry, Life Extension brand loyalists | £17.07 |
| 4 | Life Extension TMG 500mg Liquid Vcaps | 500 mg | Liquid vcap (60/bottle) | Users with capsule swallowing difficulty | £11.73 |
| 5 | Life Extension TMG Powder 50g | Flexible (typically 500–2000 mg) | Powder (50 g) | Flexible dosing, athletic-performance protocols | £16.18 |
| 6 | Swanson TMG 500mg | 500 mg | Capsule (90/bottle) | Lowest-cost-entry tester | £6.51 |
| 7 | Kirkman TMG 500mg + Folinic Acid + Methyl B12 | 500 mg + B12/folinic | Capsule (120/bottle) | MTHFR variant carriers, full methylation cofactor stack | £47.67 |
| 8 | Kirkman TMG 500mg Plain | 500 mg | Capsule (120/bottle) | Hypoallergenic / sensitive-population focus | £48.36 |
| 9 | Kirkman TMG 175mg | 175 mg | Capsule (180/bottle) | Children & sensitive populations (clinician-led) | £35.93 |
| 10 | Kirkman TMG + Folic Acid + B12 Powder 227g | Flexible (powder) | Powder (227 g) | Long-supply, high-dose homocysteine protocols | £73.22 |
| 11 | Kirkman TMG Liquid 480ml | Flexible (liquid) | Liquid (480 ml) | Children & capsule-averse users (clinician-led) | £58.01 |
| 12 | Douglas Labs Homocystrol + TMG | TMG + B-complex stack | Veggie capsule (90/bottle) | Practitioner-grade homocysteine protocol | £65.35 |
Looking to layer TMG into a wider longevity stack? See our related Harley Medic guides: [Best NMN Supplements UK] · [Best Akkermansia Supplements UK] · [Best PQQ Supplements UK] · [Best Apigenin Supplements UK] · [Best Spermidine Supplements UK] · [Best Pectin Supplements UK].
1. Welzo Ultra Purity TMG — Best TMG Supplement UK Overall
Editor’s verdict: Our best TMG supplement pick of 2026 and the best reviewed TMG product on the UK market. Price: £16.99 (down from £24.99 RRP) — a 32% saving on a clinical-strength single-ingredient formulation.
The Welzo Ultra Purity TMG is our top recommendation for 2026 because it solves the central problem in this category: most UK TMG products are either under-dosed at 175–500 mg per serving (requiring multiple capsules to hit the 1000 mg dose used in modern longevity protocols) or padded with proprietary blends that obscure how much TMG you’re actually getting.
Welzo’s formulation is deliberately minimalist: 1000 mg of pure TMG (Betaine Anhydrous) per daily serving (delivered across two capsules), in a clean vegan cellulose capsule with no fillers, binders, or bulking agents.
Complete formulation
- 1000 mg pure TMG (Betaine Anhydrous) per serving
- 2 capsules per serving (500 mg per capsule)
- 60 capsules per bottle (30 servings — 1-month supply)
- Vegan capsule (HPMC vegetable cellulose)
- Allergen-free
- Made in the UK to GMP standards
- Third-party tested for purity and potency
- No fillers, no binders, no synthetic additives, no proprietary blends
Why it’s the best reviewed TMG product on the UK market
The dose used in real longevity protocols. 1000 mg/day is the standard methyl donor pairing dose for users supplementing 250–1000 mg of NMN — the protocol popularised by Dr David Sinclair and now baked into virtually every modern longevity stack. Welzo delivers the full 1000 mg in a single 2-capsule serving without buying multiple bottles or counting capsules.
Single-ingredient transparency. When you start a TMG supplement, you want to know exactly what TMG is doing in your body — not what a proprietary blend of seven compounds is doing. Welzo’s single-ingredient approach lets you assess TMG cleanly, and add complementary methylation cofactors (methylated B12, folate, B6, zinc) as separate, transparently dosed inputs if needed.
Welzo Ultra Purity manufacturing standard. The Welzo Ultra Purity range is built around three principles: purity-first formulation, transparent dosing, and rigorous third-party batch testing. Every batch is independently analysed by accredited laboratories to verify potency and purity.
UK-made, UK-shipped. Manufactured in the UK to GMP standards — no transatlantic shipping delays, no customs friction, and inventory traceability from manufacturer to delivery address. This matters for users on consistent long-term protocols.
Trusted UK platform. Welzo is a UK-based health platform with full inventory oversight from verified manufacturers, reviewed by 200,000+ customers worldwide. Welzo’s medical content is led by Dr Sameer Nakedar, Chief Medical Officer.
Genuine value at a serious discount. At £16.99 (down from £24.99 RRP — a 32% saving), Welzo delivers a clinical-grade 1000mg TMG formulation at a price point that makes long-term protocols sustainable. For users running 8–12+ week longevity protocols, this is the single most important variable.
The ideal NMN companion. Welzo positions this product explicitly as “the standard methyl donor companion to NMN, NR, and other longevity supplements” — and the dosing matches: 1000 mg TMG pairs cleanly with 500–1000 mg NMN at the 1:1 ratio commonly recommended by Sinclair-style protocols.
Who it’s best for
- Adults aged 35+ taking NMN, NR, or other NAD⁺ precursors who want to replenish methyl groups consumed during NAD⁺ metabolism.
- People with elevated homocysteine identified through a blood test, or carriers of MTHFR or related methylation gene variants who need a folate-independent methylation pathway.
- Resistance-training athletes wanting to explore TMG’s modest ergogenic profile (modern studies use ~2.5g/day for performance — buyers can scale up by taking 2.5x the standard serving).
- Users following Dr Sinclair’s longevity protocol or any structured longevity stack alongside methylated B vitamins, omega-3, and creatine.
- Anyone who values purity, transparent dosing, and UK manufacturing over flashy marketing.
Limitations to be aware of
- Single-ingredient — users wanting a pre-built methylation cofactor stack (TMG + methyl B12 + methylfolate + B6) need to layer separately. See Kirkman or Douglas Laboratories products at #7 and #12.
- For homocysteine-targeting protocols at 4–6 g/day (the dose used in homocysteine-reduction RCTs), users will need 2–3 servings per day — at which point the powder format from Life Extension becomes more economical.
Shop Welzo Ultra Purity TMG (£16.99) →
2. NOW Foods TMG 1000mg — Best Single-Tablet 1000mg Option
NOW Foods TMG 1000mg (£18.44, RRP £21.25) provides the full 1000mg methyl-donor dose in a single tablet — useful for users who want a one-pill-per-day format. NOW Foods is a long-established US brand with strong quality control and broad UK distribution.
Per serving: 1000 mg TMG per tablet. 100 tablets per bottle (over 3 months at 1 tablet/day).
Why it’s worth considering: If you specifically prefer a single-tablet format and don’t mind the larger pill size of a 1000mg tablet, NOW Foods is a strong choice. The 100-tablet bottle delivers a 3-month-plus supply.
Best for: Single-tablet format users; NOW Foods brand loyalists.
Trade-offs:
- Tablet format is larger and harder to split than capsules; users wanting flexible dosing may prefer Welzo’s 500mg-per-capsule format.
- US-imported, so UK shipping and customs handling can add lead time vs Welzo’s UK-made supply.
3. Life Extension TMG 500mg Capsules — Best Lower-Dose Entry
Life Extension TMG 500mg (£17.07) is the standard 500mg-per-capsule option from one of the most respected longevity-focused US supplement brands. Life Extension formulations are widely used in the biohacking community.
Per serving: 500 mg TMG per capsule. 60 capsules per bottle.
Why it’s worth considering: Suits users wanting a 500mg starter dose for cautious titration, or who want flexible dosing (1 cap = 500mg, 2 caps = 1000mg). Life Extension’s brand reputation in longevity is well established.
Best for: Sleep-sensitive titrating users; Life Extension brand loyalists; users wanting flexibility between 500mg and 1000mg.
Trade-offs:
- 500mg per capsule means reaching the 1000mg longevity-protocol dose requires 2 capsules per day (same as Welzo, but at a higher price per gram of TMG).
4. Life Extension TMG 500mg Liquid Vcaps — Best for Capsule-Averse Users
Life Extension TMG Liquid Vcaps (£11.73, RRP £13.82) deliver 500mg TMG in a liquid-filled vegetarian capsule format — typically associated with faster dissolution than dry-fill capsules.
Per serving: 500 mg TMG per liquid vcap. 60 vcaps per bottle.
Why it’s worth considering: Liquid vcaps suit users with capsule swallowing difficulties or those who specifically prefer the liquid-filled format. The lowest-priced Life Extension TMG option in the UK.
Best for: Users with capsule swallowing difficulty; budget-conscious Life Extension buyers.
Trade-offs:
- Liquid vcaps must be stored carefully to avoid heat exposure.
- 500mg dose still requires 2 caps for the 1000mg longevity-protocol level.
View Life Extension TMG Liquid Vcaps →
5. Life Extension TMG Powder 50g — Best for Flexible / High-Dose Protocols
Life Extension TMG Powder 50g (£16.18) is the most format-flexible option in the Welzo TMG range. Powder allows users to scale doses across the full 500 mg–6 g spectrum without buying multiple SKUs — particularly useful for users running athletic-performance protocols (~2.5g/day) or homocysteine-reduction protocols (4–6g/day).
Per serving: Flexible — typically 1/4 to 1 teaspoon (~500 mg–2 g per serving).
Why it’s worth considering: Powder is the only practical format for users running ergogenic (2.5 g/day) or homocysteine-targeted (4–6 g/day) protocols. Reaching 4 g via capsules requires 8+ capsules per day, which is impractical.
Best for: Athletes running 2.5g/day performance protocols; users with elevated homocysteine running 4–6g/day clinical-trial-aligned protocols; users wanting maximum dosing flexibility.
Trade-offs:
- Powder requires mixing — users wanting maximum convenience may prefer capsules.
- Authentic TMG has a characteristic slightly fishy taste (a feature, not a fault) — some users find this off-putting in powder form vs encapsulated.
View Life Extension TMG Powder →
6. Swanson TMG 500mg — Lowest-Cost Entry Option
Swanson TMG 500mg (£6.51, RRP £8.51) is the lowest-cost-entry TMG option in the UK market. Swanson is a long-established US brand with broad UK distribution.
Per serving: 500 mg TMG per capsule. 90 capsules per bottle.
Why it’s worth considering: The lowest cost-of-entry option for users who want to test TMG tolerance and effect before committing to a higher-cost product. The 90-capsule bottle gives a 3-month supply at 1 capsule/day or a 6-week supply at 2 capsules/day.
Best for: First-time TMG users testing tolerance; budget-constrained buyers; users wanting an inexpensive trial bottle.
Trade-offs:
- Less granular ingredient transparency than premium brands.
- UK availability sometimes inconsistent depending on stock.
7. Kirkman TMG 500mg + Folinic Acid + Methyl B12 — Best for MTHFR Variant Carriers
Kirkman TMG 500mg + Folinic Acid + Methyl B12 (£47.67) combines TMG with two of the most important methylation cofactors — folinic acid (a metabolically active folate form) and methylcobalamin (the bioavailable B12 form). Kirkman Laboratories is a US practitioner-grade brand specialising in hypoallergenic formulations for sensitive populations.
Per serving: 500 mg TMG + folinic acid + methyl B12 per capsule. 120 capsules per bottle (4-month supply at 1 cap/day).
Why it’s worth considering: Carriers of MTHFR gene variants often have impaired folate metabolism and benefit from both TMG (folate-independent methylation pathway) and methylated folate forms. This formulation delivers both in one product. It’s also a useful all-in-one for users who don’t already take methylated B-complex.
Best for: MTHFR variant carriers; users with elevated homocysteine; those wanting a complete methylation cofactor stack in a single capsule.
Trade-offs:
- Premium pricing relative to plain TMG products.
- For users who already take methylated B-complex, the cofactors are redundant.
View Kirkman TMG + Folinic + B12 →
8. Kirkman TMG 500mg Plain — Best Hypoallergenic Standalone
Kirkman TMG 500mg Plain (£48.36) is the standalone TMG version from Kirkman Laboratories, a brand specifically focused on hypoallergenic formulations for sensitive populations including users with autism spectrum or chemical sensitivities.
Per serving: 500 mg TMG per capsule. 120 capsules per bottle.
Why it’s worth considering: Kirkman’s manufacturing protocols are specifically designed for ultra-clean formulations free from common allergens and additives. Useful for users with chemical sensitivities or specific dietary restrictions.
Best for: Users with chemical sensitivities or specific allergen restrictions; practitioner-led protocols.
Trade-offs:
- Premium pricing relative to standard brands like Welzo, NOW, or Swanson — useful only if you specifically need Kirkman’s hypoallergenic positioning.
9. Kirkman TMG 175mg — Best for Children & Sensitive Populations
Kirkman TMG 175mg (£35.93) is a low-dose TMG formulation specifically designed for paediatric and sensitive-population use under clinician supervision.
Per serving: 175 mg TMG per capsule. 180 capsules per bottle.
Why it’s worth considering: The 175mg dose allows clinician-led titration in children or sensitive adults. Used primarily in autism spectrum and methylation-disorder protocols under medical supervision.
Best for: Paediatric clinician-led protocols; ultra-sensitive adult populations.
Trade-offs:
- Not suitable for adult longevity or homocysteine protocols (would require 6+ capsules to reach the 1000mg standard dose).
- Should only be used under clinician supervision.
10. Kirkman TMG + Folic Acid + B12 Powder 227g — Best Long-Supply Powder Stack
Kirkman TMG + Folic Acid + B12 Powder 227g (£73.22) provides a long-supply powder format combining TMG with folic acid and B12 for users running structured methylation protocols.
Why it’s worth considering: The 227g bottle is large enough to support 4–6 g/day high-dose homocysteine-targeting protocols for several months. Combined methylation cofactors in one powder.
Best for: Long-supply structured methylation protocols; high-dose homocysteine-targeted users.
Trade-offs:
- Significant upfront cost.
- Powder format requires mixing.
11. Kirkman TMG Liquid 480ml — Best for Users Who Cannot Take Capsules
Kirkman TMG Liquid 480ml (£58.01) is a liquid TMG formulation in a 480ml bottle designed for paediatric or capsule-averse users under clinician supervision.
Why it’s worth considering: The only true liquid TMG format in this line-up. Suits children or adults who cannot swallow capsules and need flexible liquid dosing.
Best for: Children and paediatric protocols (clinician-led); adults with severe swallowing difficulties.
12. Douglas Laboratories Homocystrol + TMG — Best Practitioner-Grade Homocysteine Stack
Douglas Labs Homocystrol + TMG (£65.35) is a practitioner-grade comprehensive homocysteine-management formulation combining TMG with a full B-vitamin methylation cofactor stack.
Why it’s worth considering: Practitioner-formulated complete stack for users with elevated homocysteine identified through blood testing — typically prescribed by integrative or functional medicine clinicians.
Best for: Practitioner-led homocysteine management protocols.
How to take TMG: Practical dosing protocol
TMG dosing depends on your goal. Three main protocol tiers are used in the published evidence:
Methylation support / NMN companion: 500–1000 mg/day
- Standard NMN companion dose: 1000 mg/day (the dose used in Sinclair-style longevity protocols at the 1:1 NMN:TMG ratio). Welzo Ultra Purity TMG = exactly this dose in 2 capsules.
- Lower-dose maintenance: 500 mg/day for users on standard NMN doses (250–500 mg) who want methyl donor support without going to the full 1000 mg.
- Timing: Take with food, typically in the morning alongside your NMN. Some users split into morning and evening.
Athletic performance: ~2.5 g/day
- Resistance training dose: 2.5 g/day (the dose used in Cholewa et al. 2014 review of athletic performance studies). Practical via 5 capsules of 500mg TMG, or 2.5 g of powder.
- Timing: Take 30–60 minutes before training, often split into pre-workout (1.25 g) and post-workout (1.25 g).
- Best format: Powder is more economical at this dose level.
Homocysteine reduction: 4–6 g/day
- Clinical-trial-aligned dose: 4–6 g/day (the dose used in McRae 2013 meta-analysis of 5 RCTs). This is the dose that produced an ~11.8% homocysteine reduction.
- Best format: Powder is the only practical format at this dose level — capsules would require 8–12 per day.
- Caveat: Doses ≥4 g/day for ≥6 weeks may moderately raise LDL cholesterol and triglycerides (Olthof 2005, Ashtary-Larky 2021 meta-analyses). Monitor lipid panel under clinician supervision.
- Only run high-dose protocols under clinician supervision — particularly if you have known cardiovascular risk factors.
Stacking TMG with complementary compounds
TMG is mechanistically complementary to several other longevity and methylation compounds:
- NMN / NR — the standard pairing. NMN raises NAD⁺ levels; TMG replenishes methyl groups consumed during NAD⁺ metabolism. Sinclair-style 1:1 ratio.
- Methylated B12 (methylcobalamin) — methionine synthase pathway cofactor; complements TMG’s BHMT pathway.
- Methylfolate (5-MTHF) — the active folate form; particularly important for MTHFR variant carriers.
- Vitamin B6 (P5P) — cofactor for the trans-sulfuration pathway that processes methionine downstream.
- Zinc — cofactor for several methylation enzymes.
- Trans-Resveratrol, Spermidine, Apigenin — different longevity mechanisms (sirtuin activation, autophagy, CD38 inhibition); TMG provides the methylation foundation underneath.
How long until I notice anything?
TMG works through cumulative methylation support — most subjective benefits build over weeks to months. Some users notice subtle improvements in energy, mental clarity, or workout recovery in the first 2–4 weeks. Homocysteine reduction in clinical trials is typically measured at 6–24 weeks. Athletic performance improvements emerge over 4–8 weeks of consistent use combined with training.
Safety, side effects, and who should be cautious
TMG is generally well tolerated at supplemental doses. The McRae 2013 meta-analysis and individual RCTs at 4–6 g/day for up to 24 weeks reported good tolerability. Most modern longevity protocols at 500–1000 mg/day are well below the doses where lipid concerns have been documented.
Mild side effects occasionally reported include:
- Mild gastrointestinal effects (nausea, diarrhoea) at higher doses, particularly when started without titration.
- A characteristic mildly fishy odour or taste — this is a normal feature of authentic TMG, not a quality issue.
- Mild sleep changes or vivid dreams in some users (usually transient).
Speak to your GP or a qualified healthcare professional before starting TMG if you have:
- Pregnancy or breastfeeding — supplemental TMG has not been adequately studied in pregnancy. Defer or discuss with your GP/midwife.
- Children under 18 — paediatric use should only be under clinician supervision (e.g. Kirkman 175mg under specialist care).
- Existing high LDL cholesterol or cardiovascular risk — particularly relevant at doses ≥4 g/day, where lipid increases have been documented in meta-analyses. Discuss with your prescriber and monitor your lipid panel.
- Kidney disease or impaired renal function — early studies in renal patients showed TMG could raise cholesterol. Discuss with your nephrologist.
- Active depression or low mood — high doses of TMG may rarely cause low mood or confusion in some users.
- Anyone taking prescription medication — particularly those affecting methylation pathways or homocysteine metabolism.
TMG is sold in the UK as a food supplement. It is not a licensed medicine and is not approved to prevent, treat, or cure any disease, including cardiovascular disease, MTHFR-related conditions, or methylation disorders. It should be viewed as a well-tolerated methylation adjunct to evidence-based lifestyle interventions — not a replacement for them.
Frequently asked questions about UK TMG supplements
What is the best TMG supplement in the UK in 2026?
Based on our doctor-led ranking of dose, source form, purity, manufacturing standard, transparency, and value, Welzo Ultra Purity TMG is the best TMG supplement UK 2026 — and the best reviewed TMG product on the UK market. It delivers 1000mg of pure trimethylglycine per serving (the standard methyl donor pairing dose for NMN protocols), is manufactured in the UK to GMP standards, is third-party tested, and contains no fillers or proprietary blends — at £16.99 (down from £24.99 RRP).
Is TMG the same as betaine anhydrous?
Yes — TMG (trimethylglycine) and betaine anhydrous are the same compound, just two different names. “Betaine anhydrous” is more common on supplement labels in the US; “TMG” is more common in longevity/biohacking communities. Both refer to the methyl-donor form. They are distinct from betaine HCl, which is a different supplement used to support stomach acid for digestion. For methylation and longevity purposes, you want anhydrous betaine (TMG).
How much TMG should I take per day?
Dose depends on your goal:
- NMN companion / methylation support: 500–1000 mg/day
- Athletic performance: ~2.5 g/day
- Homocysteine reduction: 4–6 g/day (clinical-trial dose, only under clinician supervision)
Most longevity-protocol users settle at 1000 mg/day — the dose Welzo Ultra Purity TMG delivers in a single 2-capsule serving.
Should I take TMG with NMN or NR?
Yes, and many longevity protocols do exactly that. NMN supplementation increases methyl group consumption during NAD⁺ metabolism (specifically the methylation of nicotinamide for excretion), and TMG is commonly used to replenish methyl donors as a precaution. Dr David Sinclair takes 500–1000 mg TMG daily alongside his NMN. The standard ratio is 1:1 NMN:TMG. For doctor-reviewed product comparisons, see our guide to the best NMN supplements UK 2026.
Can I take TMG without NMN?
Absolutely. TMG has independent benefits beyond NMN pairing — homocysteine reduction at higher doses, methylation support for MTHFR variant carriers, athletic performance support for resistance-trained users, and liver support through phosphatidylcholine synthesis. Many users take TMG independently for these benefits.
When should I take TMG?
TMG can be taken with or without food. Many users take it in the morning alongside a methylated B-complex and their NMN. If using higher doses (above 1 g/day), splitting into morning and evening doses can improve tolerability. For athletic-performance protocols (2.5 g/day), splitting into pre-workout and post-workout doses is common.
Why does my TMG smell slightly fishy?
A mild fishy odour or aftertaste is a normal feature of authentic TMG, not a quality issue — it’s a characteristic of the compound itself. If anything, the absence of any odour can indicate the product is heavily processed or contains masking agents.
Does TMG raise cholesterol?
This is the most important caveat in the TMG evidence base. Meta-analyses (Olthof 2005, Ashtary-Larky 2021) have shown that doses ≥4 g/day for ≥6 weeks moderately raise LDL cholesterol and triglycerides in healthy adults. This counteracts some of the cardiovascular benefit of homocysteine reduction. For most longevity-protocol users at 500–1000 mg/day, this is not a documented concern. Anyone considering doses ≥4 g/day should monitor their lipid panel and ideally do so under clinician supervision.
Is TMG safe with high blood pressure or heart medication?
TMG is generally well tolerated. However, anyone on cardiovascular medication or with existing high LDL cholesterol should discuss TMG supplementation with their prescriber, particularly if considering doses ≥2 g/day. The published cholesterol caveat at high doses warrants caution in cardiovascular risk populations.
Can TMG help with MTHFR gene variants?
Yes — this is one of TMG’s most clinically relevant uses. MTHFR variants impair the folate-based methylation pathway, leaving people more reliant on the alternative BHMT (betaine-homocysteine methyltransferase) pathway that uses TMG as a methyl donor. Up to 40% of the population may carry one or both MTHFR variants. TMG provides a folate-independent methylation route that’s particularly valuable for these individuals. Pairing with methylfolate and methyl B12 covers the broader methylation cycle.
What’s the difference between TMG and SAMe?
SAMe (S-adenosylmethionine) is the universal methyl donor — the actual molecule used in the cell to perform methylation. TMG donates a methyl group to homocysteine, which gets recycled back to methionine, which then becomes SAMe. So TMG is upstream of SAMe in the methylation cycle. TMG is more stable, less expensive, and easier to formulate than SAMe — but SAMe acts more directly. For longevity and NMN-pairing purposes, TMG is the standard choice; SAMe is sometimes used clinically for mood support or joint health.
How long does TMG take to work?
Effects build over weeks to months. Some users notice subtle improvements in energy, mental clarity, or workout recovery in the first 2–4 weeks. Homocysteine reduction in clinical trials is typically measured at 6–24 weeks. Athletic performance improvements emerge over 4–8 weeks of consistent use combined with training. For methylation support paired with NMN, the benefit is conceptually preventative — supporting the methyl pool that NAD⁺ metabolism consumes.
Can I take TMG long-term?
For healthy adults at 500–1000 mg/day, the published evidence supports good long-term tolerability. Multi-decade dietary intake of betaine from foods like beetroot and spinach has no documented safety concern. The lipid caveat applies primarily to ≥4 g/day for extended periods, not to standard methylation-support doses. As with any long-term supplement, periodic review with your GP is sensible.
Where can I buy genuine TMG supplements in the UK?
Buy only from reputable, UK-based platforms with verified manufacturer sourcing such as Welzo’s TMG collection, which carries Welzo Ultra Purity, NOW Foods, Life Extension, Swanson, Kirkman Laboratories, and Douglas Laboratories — all with full inventory traceability and direct manufacturer-verified sourcing.
Final word on the best TMG supplements UK 2026
TMG (trimethylglycine, betaine anhydrous) sits in a rare category among supplements: a compound with both a clear molecular mechanism (methyl donation via the BHMT pathway), a substantial human clinical evidence base (multiple RCTs and meta-analyses for homocysteine reduction and athletic performance), and a clear practical use case (the standard methyl-donor companion to NMN and NR in modern longevity protocols).
The challenge in 2026 isn’t whether TMG works — the mechanistic case and clinical evidence are well-established. The challenge is whether the specific product you buy delivers a clinically meaningful 500–1000 mg dose of pure TMG without fillers, in a format that fits your protocol, at a sustainable cost.
On every clinical criterion that matters — dose, purity, transparency, manufacturing standard, third-party testing, and cost-per-effective-dose — Welzo Ultra Purity TMG (£16.99) is our best TMG supplement pick for 2026. It delivers the full 1000mg longevity-protocol dose in a clean, single-ingredient capsule manufactured in the UK to GMP standards and third-party tested for purity. Among the best TMG supplements UK consumers can purchase right now, this is the best reviewed TMG product on the market — and our editor’s first recommendation.
Shop the full Welzo TMG collection →
Editorial standards and disclosure
This article is part of Harley Medic’s editorial commitment to evidence-led supplement reviewing. Our medical content is developed independently from commercial product teams. TMG supplements are sold in the UK as food supplements and are not licensed medicines. The information in this article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any new supplement, particularly if you are pregnant, breastfeeding, take prescription medication, have elevated cholesterol or kidney disease, or have an underlying medical condition.
Key clinical references
- McRae MP. Betaine supplementation decreases plasma homocysteine in healthy adult participants: a meta-analysis. Journal of Chiropractic Medicine. 2013;12(1):20–25.
- Olthof MR, van Vliet T, Verhoef P, Zock PL, Katan MB. Effect of homocysteine-lowering nutrients on blood lipids: results from four randomised, placebo-controlled studies in healthy humans. PLoS Medicine. 2005;2(5):e135.
- Cholewa JM, Wyszczelska-Rokiel M, Glowacki R, et al. Effects of betaine on performance and body composition: a review of recent findings and potential mechanisms. Amino Acids. 2014;46(8):1785–1793.
- Ashtary-Larky D, Bagheri R, Ghanavati M, et al. Effects of betaine supplementation on cardiovascular markers: a systematic review and meta-analysis. Critical Reviews in Food Science and Nutrition. 2022;62(23):6516–6533.
- Schwab U, Törrönen A, Toppinen L, et al. Betaine supplementation decreases plasma homocysteine concentrations but does not affect body weight, body composition, or resting energy expenditure in human subjects. American Journal of Clinical Nutrition. 2002;76(5):961–967.
- Day CR, Kempson SA. Betaine chemistry, roles, and potential use in liver disease. Biochimica et Biophysica Acta. 2016;1860(6):1098–1106.
- Craig SAS. Betaine in human nutrition. American Journal of Clinical Nutrition. 2004;80(3):539–549.
