Nutrition

Ketone Esters, Once a British Olympic “Secret,” Now Widely Available

But do they work to improve endurance performance? The evidence, so far, is mixed.

Recent newspaper reports have revealed that Great Britain’s Olympic committee encouraged British endurance athletes to try a secret supplement prior to the 2012 London Olympic Games. The supplement, made of ketone esters, was then virtually-unknown, and was clearly intended to give British athletes an advantage in the Olympics.

More on this below. But what’s important now is that ketone esters are available from commercial vendors, and have been widely investigated in the last half-dozen years. So the current question becomes: Do they work?

The answer, from the best scientific research, appears to be: Not likely. Still, success stories circulate, and more research needs to be done, especially for endurance events lasting longer than 60 minutes.

Related: Want to read more about the science of ketones? Check out this story. (Active Pass membership required.)

What Are Ketone Esters?

Ketone esters are substances that contain ketones and can induce a state of ketosis similar to what follows near-starvation or a low-carb, high-fat diet. With ketone esters, however, there is no need to drastically manipulate your diet. In fact, you could carbohydrate-load and then consume ketone esters, providing both plenty of muscle glycogen and the ability to burn more fat. (The most important ketone ester is named beta-hydroxybuterate, BHB. Ketone salts appear to present more GI tract issues and less performance-potential than BHB.)

Carbs plus fats sounds like a win-win situation for endurance performance, and some believe it is. New research is less convincing. Two systematic reviews have been published this year, neither finding support for ketone supplements and exercise performance.

The first appeared in the International Journal of Sport Physiology and Performance. It concluded “that ketone supplementation exerts no clear influence on exercise performance, from sprints to events lasting approximately 50 minutes, or metabolic, respiratory, cardiovascular or perceptual responses to exercise.” The review did note that ketones might have the potential, post exercise, to increase glycogen storage, protein synthesis and muscle repair. One 2019 study of elite Dutch cyclists supports this post-exercise hypothesis.

The second systematic review, in Advances in Nutrition, came from several U.S. Army researchers. The military would have a clear interest in any supplement that could improve physical performance and enhance cognitive function—two claims often made for ketones. After reviewing existing research, the Army scientists noted many “discordant outcomes.” This caused them to conclude that there is not “sufficient evidence to warrant recommendation of consuming exogenous ketone supplements to enhance physical performance.”

Studies on Runners

Two runner studies have also failed to produce positive results. In a 2018 paper, a team at England’s Loughborough University compared 5K time-trial performances in a randomized, cross-over trial with experienced male runners capable of running about 21 minutes. Before and during one 5K, they consumed a typical carbohydrate-based sports drink. Before another, they received a similar drink with ketone bodies. There was no difference in their 5K times between trials.

Another paper, this one from a group of Irish scientists, looked at 10K performance. It used a double-blind, randomized, cross-over design. The runners first ran for an hour at 65% of their VO2 max (easy-run effort), and then did a 10K time trial. They consumed either an 8% carb drink or a similar drink with both carbs and ketone esters.

Again, the researchers observed no differences in 10K times, or in responses to several mental challenges. They concluded that the drink with carbs-plus-ketone-esters “did not improve 10K running time trial or cognitive performance.”

Scandal?

On July 11, London’s Daily Mail newspaper reported that 91 British athletes had agreed to try a new ketone-ester product prior to the 2012 Olympics. They were told that the supplement violated no known anti-doping rules, yet were required to sign documents acknowledging that there could be no guarantee of passing doping tests. They also had to sign non-disclosure agreements saying they would not discuss their participation in the supplement program.

The project was overseen by UK Sport, the equivalent of the U.S. Olympic and Paralympic Committee. In a press release defending itself and the ketone program, UK Sport said the experimental approach was ethical, non harmful, and not forbidden by doping regulations. Further, no athletes were compelled to take the products. UK Sport said it was merely trying to develop a “high performance culture that is truly inspirational and one that will set us apart from our global competitors.” Nonetheless, it was not seeking “to win medals at any cost.”

Great Britain’s top endurance performances at London came from Mo Farah with his gold medal wins in the 5000 and 10,000 meter races, and Alistair Brownlee, who won the triathlon gold medal. Neither has been associated with the secretive ketone project.

In the Daily Mail’s initial report, British endurance stars Jo Pavey and Jon Brown both registered their disapproval of the project. A week later, the Daily Mail quoted American distance star Kara Goucher at great length. She was identified as “one of the most prominent voices in world [of] sport to speak out, not just against doping, but also against the surreal marginal and medical gains some teams engage in for athletic improvement.”

Goucher said ketones were not new to her, as she had heard rumors of U.S. runners using them. In fact, she said that in 2016 she was contacted by a manufacturer who told her: “This is why the British athletes performed so well in 2012. Do you know someone on Team USA who would want this?”

She responded, “I’m not touching this with a 10-foot pole because I have no idea if it’s legal or not.” (Goucher did not make the U.S. Olympic team in 2016, finishing fourth in the Marathon Trials.)

Now on the Market

The first company to manufacture a ketone-ester drink for the supplement market was apparently HVMN, which stands for Health Via Modern Nutrition. HVMN is based in San Francisco and supported by Silicon Valley venture capital firms. The company boasts that its ketone-ester drink took 15 years, and $60 million, to develop.

No wonder HVMN Ketone costs $33 per dose.

The product’s backstory is enticing. Much of the research was conducted by Great Britain’s Brianna Stubbs, who won two World Championship gold medals in rowing. She also, at age 12, rowed across the English Channel.

Stubbs was a college student and competitive rower when Oxford researchers offered to pay her 50 British pounds to work out on a rowing machines using different supplements. “Being paid for rowing, ideal,” she concluded. 

Before long she was talked into joining the Oxford research team and pursuing her Ph.D. in metabolic biochemistry. She’s a ketone advocate. “Ketones offer you an alternative high-grade fuel, like using higher octane petrol,” she says on a webpage extolling ketone supplements.  “Performance improvements for elite athletes are on the order of 2%. For serious amateurs, it’s more variable, perhaps up to 5 or 6%.”

In 2017, Stubbs moved to San Francisco, and joined HVMN to help bring its ketone ester product to market. She’s a shareholder in the company, though she has now moved to the Buck Institute (Novato, Cal.), which is investigating ways to help us “Live Better Longer.”

Stubbs believes that ketones can impart benefits far beyond improved endurance performances. For example, she points to ketones as a possible path to reduced diabetes and cancer risks.

Just last week, Stubbs and colleagues from the Buck Institute published a paper outlining the possible use of ketone bodies as “counter measures against respiratory viral infections.” Can you spell C-O-V-I-D?

The paper concludes “there are multiple cellular and systemic mechanisms whereby ketone bodies might impact severe viral infections, such as influenza or SARS-CoV-2.”

Okay, that’s known as reaching for the stars. If you’re more tempted by immediate personal challenges, like how to improve your marathon or triathlon times, a simple internet search for “ketone esters” and “performance” will turn up plenty of options.

Here are a few tips. Caveat emptor—buyer beware—of course. In particular, understand that many ketone products are known to cause an upset stomach. That has been one of the main reasons they aren’t more widely used. In addition, they taste bad.

Even HVMN admits that its ketone ester “tastes like it works,” whatever that might mean. Probably: Hold your nose while swallowing.

Still some get past all these obstacles. In September, 2018, Vittoria Bussi used HVMN Ketone to set a women’s world record for one hour of velodrome cycling. She covered 48.007 kilometers, roughly 29 miles. “The combination of mental lucidity and physical energy was strong and effective,” she said.