Betaine (TMG) for Strength and Power: What the Research Really Shows

Betaine TMG gets sold as a cheap, steroid-like muscle builder. It is not. The best current evidence says it is a modest supplement that may add a little to maximal strength, mostly in the legs, and does little for muscle size.

This page sits inside our evidence-based supplements guide, and betaine belongs in the “interesting, optional” bucket there, well below creatine. Below we go through what it is, what each study actually found, the dose, and the betaine HCl confusion.

What is betaine TMG, and how does it work?

Betaine is trimethylglycine (TMG), a small molecule found in grain-based foods and vegetables. Your body also makes it from choline. It has two jobs that supplement companies like to talk about.

Osmolyte. An osmolyte helps a cell hold water and keep its volume under stress, such as heat or hard exercise. The theory is that better-hydrated muscle cells may work a bit better. This is a plausible mechanism, not a proven one in lifters.

Methyl donor. Betaine can donate a methyl group to turn homocysteine back into methionine. In one trial of strength-trained men, betaine blunted a rise in a homocysteine-related marker during training (Cholewa et al., 2013). That shows a biochemical effect. It does not by itself show more strength or muscle.

Does betaine build muscle? The 2013 study and what came after

The claim started with a 6-week trial in 23 strength-trained men (4.8 years of training on average). Half took 2.5 g a day of betaine, half took placebo. Betaine users improved body composition and arm size, and bench press training volume was higher in two of the three micro-cycles. But there were no differences in bench, squat or vertical jump performance, only a non-significant trend (p = 0.07) for jump power (Cholewa et al., 2013).

Notice the sample size. Eleven people took betaine. Body composition and arm and thigh size were estimated from skinfold calipers, which are not precise.

When researchers pooled the trials, the picture flattened. A 2022 meta-analysis found betaine did not significantly change body mass, body fat percentage, fat mass or fat-free mass (fat-free mass: +0.61 kg, 95% CI -1.27 to 2.49) (Ashtary-Larky et al., 2022). Results were similar across age, sex, trial length and dose. To be fair, a 2024 narrative review read the trials more kindly, concluding that betaine improves body composition when combined with exercise (Nikrandt & Chmurzynska, 2024). A pooled meta-analysis is the stronger form of evidence here, but it is a reminder that the question is not fully closed.

Why the gap? Small trials with noisy measures can produce striking results that shrink as more studies arrive. Betaine can also shift fluid in the body, which some body composition methods read as lean mass. That second point is a possible explanation, not something these studies tested directly.

Does betaine improve strength and power?

Here the evidence is more favourable, though still mixed.

A 2017 systematic review of 7 randomized trials (all rated excellent quality) found only 2 reported strength or power gains, while 5 found no change. The author concluded there was no clear ergogenic effect, though more research was needed (Ismaeel, 2017).

A newer 2024 meta-analysis pooled 17 trials with 317 participants (21% female) using chronic betaine versus placebo. It found a significant effect on maximal strength (SMD 0.47, 95% CI 0.04 to 0.89), especially lower-body strength (SMD 0.49, 95% CI 0.01 to 0.98). There were no significant effects on upper-body strength, cycling sprint power, bench press throw power or muscular endurance. Vertical jump improved (SMD 0.36) only after one low-quality study was excluded (Zawieja et al., 2024).

Why do the two reviews disagree? The 2024 analysis had more trials, and it pooled different outcomes together, which gives more statistical power. The confidence intervals are wide, with lower bounds barely above zero, so a real effect could be tiny. A sensible reading: betaine might help a little, the effect is not guaranteed, and it is far smaller than what you get from simply adding sets, sleeping well or eating enough protein.

You will sometimes see “3-5% more power” quoted for betaine. The sources above do not give a single reliable figure like that, so treat any exact percentage with suspicion.

Betaine vs creatine: do they stack?

Creatine raises the phosphocreatine stored in your muscle. Does betaine do the same, or add to it? One 10-day, double-blind trial in untrained people tested betaine (2 g a day), creatine (20 g a day), both together, and placebo.

Creatine and creatine plus betaine raised muscle phosphocreatine and improved 1RM and power. Betaine alone did not raise phosphocreatine and did not change strength or power versus placebo. Adding betaine to creatine gave no difference over creatine alone (del Favero et al., 2012).

Caveats matter here: the participants were untrained, the trial was short, and the betaine dose was 2 g. It does not rule out small effects in trained lifters over weeks. Still, it supports a clear ranking. Start with creatine monohydrate and use our creatine dosage calculator to set the dose. Betaine is a maybe-later extra.

Betaine anhydrous dose: how much and for how long?

The trials in lifters mostly used about 2.5 g a day of betaine anhydrous, taken daily rather than just before training (Cholewa et al., 2013). The 2024 meta-analysis only included chronic supplementation and reported benefits with at least 7 days of use (Zawieja et al., 2024).

More is not clearly better. A meta-analysis of six trials using at least 4 g a day for 6 to 24 weeks found total cholesterol rose by about 0.34 mmol/L (95% CI 0.02 to 0.65), with no significant change in LDL, HDL or triglycerides (Zawieja et al., 2021). A later narrative review described total and LDL cholesterol increases at 4 g a day or more (Nikrandt & Chmurzynska, 2024). The two summaries differ on LDL, which is a good reason to stay near 2.5 g and not chase bigger numbers.

Betaine anhydrous vs betaine HCl: the stomach acid warning

These are different products with similar names. Betaine anhydrous is the form used in the sports studies above. Betaine HCl (hydrochloride) is generally sold to add stomach acid, and none of the trials in this article tested it for strength or power.

Do not treat HCl as a cheaper swap. The extra acid can irritate the stomach lining. If you have reflux, gastritis, an ulcer, or take anti-inflammatory painkillers regularly, speak to a doctor before using it. Check the label for “betaine anhydrous” or “trimethylglycine” and an exact milligram amount.

Is betaine in pre-workout worth it?

Many pre-workouts list betaine, often inside a proprietary blend that hides how much is in it. The studies used about 2.5 g daily, and a single pre-workout scoop may contain much less. Our guides on spotting proprietary blends and underdosing tricks show how to read these labels.

How to take betaine if you decide to try it

Keep it simple. Buy plain betaine anhydrous powder from a brand that publishes third-party test results, and measure 2.5 g with a scale or a scoop you have checked. None of the studies above tested timing, so take it whenever you will remember, in one go or split between two meals. Mix it into water, a shake or curd.

Do not stack three new things at once. Add betaine on its own, keep your training the same, and write down your top-set squat or leg press weight each week. A change smaller than your normal week-to-week swing is not evidence that it works. Because the likely benefit is small, a fair test needs several weeks, not a few sessions.

Who should skip betaine, or ask a doctor first?

Nothing on this page is medical advice. Talk to your doctor before using it if you:

• have high cholesterol or heart disease, given the cholesterol findings at higher doses
• have kidney or liver disease, or a metabolic condition such as homocystinuria
• are pregnant or breastfeeding, since there is little research on lifters in those groups
• take regular medication and are unsure about interactions

Evidence in women is thin. A single 8-week trial in 23 untrained young women found no extra strength benefit from betaine, though fat mass and body fat percentage dropped more than on placebo (Cholewa et al., 2018). One small study is a hint, not a recommendation.

The bottom line on betaine TMG

Betaine TMG is a small, optional extra. It does not build muscle on its own, it does not replace creatine, and the strength effect is modest and uncertain. A 2024 review of the market also noted that betaine is promoted for many different uses while clinical efficacy remains unclear (Nikrandt & Chmurzynska, 2024).

If your training, protein (dal, paneer, curd, eggs, soya), sleep and creatine are already sorted, 2.5 g of betaine anhydrous daily is a low-risk experiment for lower-body strength. Until then, put that money into food. For the full ranking, see our supplement hierarchy from proven to scam, and build the training side with our free leg day plan.