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TMG and Creatine: How They Work Together and What the Evidence Shows

TMG (trimethylglycine, also called betaine) and creatine are linked through methylation. The body uses methyl groups to make creatine, and TMG is one of the nutrients that supplies them. The link is real, but the research on taking the two together is less encouraging than the theory. In one randomised trial, adding betaine to creatine gave no extra benefit for strength or power. Creatine on its own has the stronger evidence, especially when paired with resistance training. TMG has a different, well-defined job: supporting methylation and homocysteine metabolism.

This guide explains how the two relate, what human trials found, which doses are documented, what to watch for, and how adults over 40 can think about the combination.

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TL;DR

  • Creatine production in the body uses methyl groups. TMG donates methyl groups, so the two are connected in theory.
  • In a trial of non-resistance-trained people, betaine added to creatine did not improve strength or power. Creatine alone did raise muscle phosphorylcreatine.
  • For older adults, creatine works best with at least 12 weeks of resistance training. Without training, benefits for strength are unlikely.
  • Creatine monohydrate is well tolerated in healthy people at standard doses. If you have kidney problems, speak to your doctor first.
  • Take TMG for its methylation role, not as a way to boost creatine results.

Table of Contents

What TMG and creatine each do

TMG: a methyl donor

TMG is a compound found in foods such as beetroot, spinach and wheat. In the body it donates a methyl group to convert homocysteine into methionine. Research on methylation demand and homocysteine metabolism describes this role. That is why TMG appears in supplements aimed at methylation and homocysteine support.

We cover the mechanism in more detail in our guide TMG for NMN users: methylation mechanism and dose, and the homocysteine angle in our article on lowering homocysteine with TMG.

Creatine: fuel for short, intense effort

Creatine is stored in muscle as phosphorylcreatine and is used for quick bursts of energy. The Dutch Voedingscentrum states on its creatine page that creatine monohydrate can help performance during short, intense efforts. It also lists common effects: weight gain from water retention and, in some people, gastrointestinal complaints.

The International Society of Sports Nutrition (ISSN) goes further. Its position stand describes creatine monohydrate as the most effective ergogenic nutritional supplement currently available to athletes for increasing high-intensity exercise capacity and lean body mass during training.

The body makes creatine from arginine, glycine and a methyl group donated by SAMe. Making creatine therefore uses up methyl groups, and TMG can help refill that supply through the homocysteine pathway. This is the logic behind pairing them.

Why people combine TMG and creatine

The reasoning is simple. Creatine synthesis consumes methyl groups. TMG donates them. If your methyl supply is stretched, more TMG might support it. Some sports nutrition pages also suggest betaine may help resistance exercise that involves high muscular endurance and metabolic stress. Examine’s betaine overview calls the evidence mixed, and says betaine may help in protocols that challenge muscular endurance with high levels of metabolic stress.

Theory and outcome are different things, though. The next section looks at what happened when researchers tested the pair.

What human trials show

The main trial on creatine plus betaine

The most cited study is a randomised, placebo-controlled trial, Creatine but not betaine supplementation increases muscle phosphorylcreatine content and strength performance. Its findings:

  • Creatine, and creatine plus betaine, increased muscle phosphorylcreatine and power on some measures compared with placebo.
  • There was no significant difference between the creatine group and the creatine-plus-betaine group.
  • Betaine alone had no ergogenic effect.
  • In non-resistance-trained subjects, combining betaine with creatine did not affect strength or power performance, and the authors found no synergy.

In plain terms: creatine did the work. Betaine did not add to it in this group.

What this does and does not mean

One trial in one population does not close the question. It involved people without resistance-training experience, and it tested performance outcomes, not methylation markers. It does not show that TMG is harmful alongside creatine. It shows that, for strength and power, there was no measurable gain from adding it.

If your goal is more strength from creatine, the evidence points to training and consistent creatine use, not to an add-on.

Creatine after 40: what the research says about ageing

Many of our readers are 40 or older, or buy for older relatives. For this group, the creatine research is more specific.

  • A systematic review by Stares and Bains found that in healthy older adults, the clearest potential benefits came when daily creatine was combined with at least 12 weeks of resistance training. The benefits were mainly in strength, functional capacity and lean mass. The authors called for more long-term trials.
  • A 2025 systematic review and meta-analysis covered 20 studies and 1,093 older participants. Creatine plus exercise significantly improved one-repetition-maximum strength and reduced body-fat percentage. It did not significantly improve total-body bone mineral density.
  • A 2024 critical review of supplements for healthy ageing reports that creatine can increase muscle mass, strength and function in older adults. Without resistance training, it is unlikely to improve strength or functional performance. Evidence for cognition remains conflicting.

Some researchers also argue that creatine should be regarded as a conditionally essential nutrient. That is a perspective, not a settled conclusion, but it explains the growing interest.

Is there evidence for TMG and creatine together in longevity?

Not directly. We found no human trial testing the combination for healthy ageing or lifespan. What exists is separate: creatine plus training for muscle and function in older adults, and TMG for methylation and homocysteine. Treat any claim that the pair extends life as unproven.

Doses that have been studied

Creatine

The ISSN position stand describes two approaches for creatine monohydrate:

Approach Protocol
Loading 5 g four times daily for 5 to 7 days, then 3 to 5 g per day
Gradual 3 g per day for 28 days, which slowly raises muscle creatine

The gradual route avoids the large early doses. It takes longer to saturate the muscle, but it reaches a similar point.

TMG

TMG is typically taken in the gram range. Our guides discuss a 3 to 6 g daily dose and recommend starting at 0.5 to 1 g to see how you tolerate it. For reference, 3 g equals six 500 mg capsules, and 6 g equals twelve. Starting low and building up is a sensible way to approach this.

Timing

No trial we found shows a benefit from taking TMG and creatine at the same moment. Consistency matters more than the clock. For TMG, our article on when to take TMG covers food and routine. For creatine, daily use matters more than whether it comes before or after training.

Safety: what to know before combining them

Creatine in healthy adults

The ISSN confirms that creatine monohydrate at standard doses (for example 5 g per day) is well tolerated and effective at raising muscle creatine. It finds no credible evidence of adverse health risks in healthy individuals. Its review also found no evidence that creatine increases the commonly reported dehydration or muscle cramping.

A review of creatine safety studies reports no change in liver or kidney function in healthy people supplemented with creatine, including over several months.

A review of long-term safety from the EU’s Scientific Committee on Food took a more cautious line. It found large, well-controlled long-term studies lacking, advised avoiding high loading doses, and considered doses up to 3 g per day unlikely to pose a risk. Its opinion is from 2000, so later research has added to the picture. It is still a reason to prefer the gradual 3 g route if you want to be conservative.

Creatine in healthy adults — overview diagram

Kidneys

This is the most important caution. The 2024 review notes that controlled trials in healthy adults generally find recommended-dose creatine does not harm renal function. Safety is less clear in people with pre-existing kidney disease, and it advises consulting a nephrologist.

The Dutch Sportzorg e-book Supplementen in de praktijk lists kidney disease as a risk group for creatine. It adds that creatine can falsely raise serum creatinine, which complicates kidney-function assessment. It advises against use in patients with kidney problems without a medical reason.

If you have a kidney condition, or you have blood tests for kidney function coming up, tell your GP or specialist that you take creatine.

Medicines and other supplements

The NVWA, the Dutch food safety authority, gives practical advice in its guidance on supplement risks. Read the label and the leaflet of any medicine. Check whether supplements can be combined with your medicines. Do not exceed the recommended daily dose. See a doctor or pharmacist if a medicine seems less effective or new side effects appear.

This matters most for older adults who take several medicines. If a family member does, ask their pharmacist before adding either supplement.

Practical ways to use TMG and creatine

  1. Decide on your goal. For strength and muscle, creatine plus resistance training has the evidence. For methylation and homocysteine, TMG is the relevant supplement.
  2. Start with one change at a time. If you add both on the same day and feel unwell, you cannot tell which caused it.
  3. Build TMG up gradually. Begin at 0.5 to 1 g and increase if you tolerate it.
  4. Use a conservative creatine dose. The ISSN describes 3 g per day as an effective gradual route.
  5. Train. In older adults, creatine without resistance training is unlikely to improve strength.
  6. Give it time. The research on older adults uses periods of at least 12 weeks.
  7. Check with a professional if you have kidney disease or take regular medicines.

Other sources of TMG

TMG also comes from food, so a supplement is not the only route. If you eat a varied diet with beetroot, spinach and whole grains, you already take in some. A supplement gives a measured amount in a defined dose.

Our perspective

At Vivetus we work with ingredients that have a clear mechanism and a human evidence base. TMG fits that description for methylation, which is why we sell it alongside NMN, where methyl demand rises. Creatine is a separate category, and we do not sell it.

Our perspective — overview diagram

Our view is that the two should not be sold as a stack. The best direct trial found no extra benefit from adding betaine to creatine. We would rather tell you that than imply a synergy the data do not show.

What we do stand behind is simple. Take TMG for what it does. Use creatine for what it does, with training. Keep doses modest, change one thing at a time, and ask a pharmacist or doctor if you take medicines or have kidney concerns. Our products are vegan, assembled in the Netherlands and made with transparent formulations, so you can see what each capsule contains.

— Jord

TMG from Vivetus

If you want TMG for methylation and homocysteine support, our Vivetus® Trimethylglycine (TMG), 60 capsules of 500 mg is the product to look at. You can also browse the full TMG and supplement range. Orders over €50 ship free. If you already use NMN, our article on TMG and NMN together explains why the two are often paired.

Vivetus® Trimethylglycine (TMG) - 60 capsules - 500mg

FAQ

Can you take TMG and creatine together?

Yes, there is no evidence in the studies we reviewed that the combination is harmful for healthy adults at standard doses. The main trial found no added benefit from the pair for strength or power. Check with a doctor or pharmacist first if you take medicines or have kidney disease.

Does TMG make creatine work better?

In the randomised trial we reviewed, it did not. Creatine alone and creatine plus betaine both raised muscle phosphorylcreatine, with no significant difference between them. The theory about methyl groups is sound, but it did not translate into better performance in that study.

What should you take with TMG?

That depends on your goal. For methylation support, people often pair TMG with NMN, as explained in our guide to TMG and NMN. For muscle, the evidence points to creatine with resistance training, not to TMG. Ask a pharmacist before combining anything with medicines.

When should you take TMG for muscle growth?

We found no trial showing a timing advantage for muscle growth, and the evidence for betaine and muscle is mixed. Consistent daily use matters more than the exact hour. Our guide on when to take TMG covers food and routine.

Is creatine safe for older adults?

In healthy adults, controlled trials generally find recommended doses do not harm kidney function. Safety is less clear in people with existing kidney disease, and specialists advise consulting a nephrologist. It also helps to know that creatine can raise serum creatinine readings, so tell whoever reads your blood tests.

Sources

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