Blog Post

Betaine Supplementation for Athletes: Is it Worth Taking?

Betaine Supplements

Betaine is a supplement that has been around the bodybuilding and strength sports community for a while. It is not one of the most frequently used supplements, but there still is a bit of buzz about it.

It is also known as trimethylglycine, or TMG.

One aspect as to why there is hype behind it is that farmers have been using it with livestock for decades now to increase muscle and reduce fat. And obviously, farmers are concerned with making money, so would not be doing this if they did not think that the money invested in betaine was going to pay off in improved profits.

This then begs the obvious question of whether it is effective in humans looking to gain muscle or lose fat.

There has been human research on that topic, so this article will aim to cover that in combination with interpretations of that research.

What is Betaine?

Betaine is naturally found in our bodies. We produce it in our own bodies, and it is also found in food.

Our intake through food has been reported to average 0.1-0.4g of betaine, coming through sources like beetroot, broccoli, grains and spinach.

Betaine Containing Foods

But most people reading this will be interested in supplementation, which typically occurs in 1-9g dosages. These supplements are normally produced as a by-product of sugar beet processing.

What Are the Proposed Benefits?

There are a lot of proposed benefits to betaine beyond even just body composition.

It helps produce carnitine which is involved in fat transportation. But it also is involved in liver function, cellular reproduction and it helps the body metabolise homocysteine.

The homocysteine aspect is particularly relevant for those with a genetic condition that leads to excessive homocysteine build-up in the body.

Homocystein Metabolism

The proposed benefits most people reading this will care about though is that it has been reported to increase muscle growth, fat loss and muscular endurance.

What Is the Mechanism Behind How It Could Help?

The mechanisms for how it can help are complex and varied. Listing a few simplified options:

  1. Betaine can influence multiple pathways and enzymes associated with fat metabolism, which can help reduce the storage of fat and increase the oxidation of fat. One example of this is the increase in carnitine.
  2. It can change the mitochondrial content of fat cells, giving them more characteristics of “brown fat.” This can lead to slightly more energy expenditure and an increase in fat loss.
  3. Reducing homocysteine levels might increase fat oxidation.
  4. Betaine could increase growth hormone and IGF-1 levels which could contribute to increased muscle protein synthesis.
  5. It draws fluid into the muscle, which potentially could help trigger muscle protein synthesis.
  6. Increased nitric oxide levels can lead to slightly more reps being able to be performed on higher rep sets, as well as better pumps due to improved blood flow.
Betaine Mechanism of action

There are even more mechanisms that have been proposed beyond these. But the biggest point is that there are a LOT of potential mechanisms.

And this is partly why I think focusing on outcomes is even more important than just mechanisms.

If the research consistently shows that something leads to significant fat loss and/or muscle gain, that is probably something that means more than whatever the proposed mechanism is.

What Does the Research Show?

As you can imagine, the research is mixed.

Because let’s be real, if something worked super consistently in the research AND had been well studied, most people who care about muscle growth and fat loss would want to know about it.

A review of all the research on betaine on body composition up until 2014 came to the conclusion that betaine has the potential to improve fat loss, muscle gain and muscular endurance.

A review focused the research on strength and power up until 2014 found that 2 of the 7 studies found significant improvements. But that obviously means that 5 of the 7 did not.

That does not sound overly promising. But digging deeper, the ones that found improvement showed around a 25% improvement on average.

Improving by 25% is dramatic, which is part of why some people are excited about it. There is still some promise, even if it is not super consistent.

A 2019 review including 6 studies and 195 participants found no change in body mass, but significant reductions in body fat. The average reduction in body fat was 2.25kg. Since there was no change in body mass, that means lean mass increased by around 2.25kg as well. So that is quite promising.

Betaine Outcomes for Body Composition
Image credit to Stronger by Science (

While there is some promise, the research is hit and miss. My interpretation is that on average there might be a small improvement in body composition and therefore strength/power, if there is any change.

How to Take?

The standard recommendation would be 2.5-5g per day, taken at any time. It is something that builds up in your system over time, so timing is not super relevant.

Most studies utilise between 1-9g per day. And if benefits are seen, they can often be seen within as little as two weeks. But it is typically something you just take indefinitely.

There is also a chance that the optimal dosage is higher than what is typically studied.

Theoretically >10g is safe. But there are minor concerns about betaine potentially having downsides related to cholesterol/triglycerides if consumed in higher amounts. So, I would not recommend playing around with that with monitoring things from a medical perspective and having expert guidance.

This is more just to highlight that there is potential that the recommended dosage might change as more research is performed. And also highlight that if this turns out to be the case, the benefits of betaine might be more consistent than what the research currently indicates.

Is Betaine Worth Taking?

Personally, I view betaine as a low priority supplement. It may or may not be something you personally want to take.

I have written a post on supplements and I would recommend reading that before purchasing betaine.

Basically, betaine might help. It has some positive research, but it is mixed. If it does help, the effect size is likely small.

It makes sense to prioritise supplements that have a higher likelihood of being effective first. And then if you still have spare money that you would like to spend on supplements AND have interest in taking betaine, it could be worth adding in addition.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.