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A new review study points toward post-exercise ketone supplementation as a way to improve adaptation and performance. What does the uncertain science mean for endurance athletes?

I heard about athletes supplementing with ketones sometime in the mid-2010s. A company reached out, promising the next big breakthrough in endurance performance from this liquid supplement composed of a molecule naturally produced in the body from the breakdown of free fatty acids. They told me that the top cyclists in the world were already using ketones and that it was destined to take over running, too. They sent a few boxes…and they collected dust in the pantry. It felt like a biohack, and I wasn’t comfortable with it.

Over the years, more studies on ketone ingestion emerged, and I started to get more and more intrigued. Rumors came out that about 70 percent of the cycling peloton used the stuff. But they cost a ton, and it was hard to discern what was actual practice and what was just marketing.

It wasn’t until 2023, though, that I embraced that ketones were here to stay, whether I liked it or not. A 2023 study in the American Journal of Physiology-Endocrine and Metabolism had nine men complete two cycling trials, both with one hour consisting of two minutes at 90 percent of aerobic capacity (moderately hard), followed by two minutes at 50 percent of aerobic capacity (very easy). In both trials, the cyclists consumed a carb-protein drink immediately after exercise and at one, two, and three hours later. Here’s the study intervention: in just one trial, participants ingested 0.29 g/kg ketone monoester immediately after exercise and at one and two hours later.

The ketone trial led to 20 percent higher levels of natural erythropoietin (EPO) in the bloodstream.

For comparison, a 2005 study in the British Journal of Sports Medicine found that the initial exposure to altitude training increased EPO by an average of around 50 percent in swimmers, with large individual variability (returning to baseline after a couple of weeks of altitude training), with lots of variation across studies. Given that our bodies produce EPO to increase red blood cell production, and red blood cells transport oxygen that power endurance performance, the ketone study indicated that we could be seeing a supplement that supercharges adaptation and performance.

Context for Ketones

To be 100 percent honest, I was sad when I saw this study. I love performance physiology, but I don’t want to think about a new biohack. Maybe it’s a sign that I’m getting old when a study on cutting-edge science just makes me tired. Get these research protocols off my lawn!

But I also couldn’t bury my head in the sand (though that would probably increase EPO concentrations via hypoxia). Instead of giving into my old-coach fatigue, maybe I can help publicize the emerging science so fewer athletes have an information disadvantage. My final push was last week when a fantastic review article was published in the American Journal of Physiology-Cell Physiology by Ruben Robberechts and Chiel Poffé. If ketone supplementation has the potential that some think it may, the article could be a key step in the future of exercise physiology.

Before getting to the science, I think it’s important to lay out the stakes. Based on the articles (mixed with a heaping dose of gossip), I can see three different scenarios unfolding over the next 10 years.

One, post-exercise ketones don’t live up to their promise, and this is all a nothingburger. That outcome would please me the most, and we all know that what’s most important in science is my pleasure. If researchers did this type of theoretical analysis on other interventions (i.e. heat training, Vitamin D, lifting, ashwagandha, strides, beta-alanine, doubles, creatine), they could come back with similar findings. We are only talking about a few intervention studies and lots of theory, and future research could have different results. Plus, some critics would already be confident making their judgments as the Supreme Court of Nothingburgerland.

Two, ketones could become a more commonly used supplement with benefits for performance and health (like iron). They are expensive, which isn’t great, but maybe they will help athletes be healthier and faster, with limited side effects. On the flip side, maybe more research indicates tradeoffs that lead to benefit:risk calculations with performance or health. Over email, Dr. Poffé–an author of the review study and a key researcher in this field–says that “studies have shown divergent effects on performance depending on the exercise context and whether you take them before, during or after exercise.” Even if they are beneficial in some contexts, it’s not a simple equation of take ketones = get faster.

The third possibility is that they are banned as an illegal performance enhancer. I have no inside info on whether that’s a possibility, and at first blush, it doesn’t seem likely without some health risks. Dr. Poffé says “I honestly don’t see much of a reason to ban ketones while allowing other ergogenic supplements.”

So, yeah, we’re talking about a wide range of possibilities, which makes sense given the uncertain mechanisms and effects at play. Let’s dig in. (We got even deeper into the nuance on our podcast this week, which you can listen to here.)

Introduction to Ketones

As stated by the review study, ketone bodies “are molecules that are continuously produced from the breakdown of free fatty acids,” primarily in the liver. Ketone body production is upregulated during periods of low carbohydrate availability—that’s why you have heard “ketosis” thrown around for ultrarunners who practice low carbohydrate, high-fat nutrition, aiming to improve fat oxidation and avoid bonking. Ketosis via nutritional interventions comes with way too many downsides for endurance athletes, though, including everything from reduced bone density to diminished high-intensity performance. That makes sense intuitively because low carbohydrate availability is extremely stressful on most body functions, especially the endocrine system.

Ketone esters, enter stage left. Researchers figured out how to create an ester bond between a ketone body precursor and a ketone body (first in 1978 in rats, but not undergoing human testing until 2012). These ketone esters cause a “rapid and transient increase in ketone bodies,” possibly inducing ketosis. It was as if this evolutionary mechanism honed over millions of years now had a dimmer switch. For the chemistry nerds out there, you can probably guess what oral ingestion of an ester is like—not fun. Companies like HVMN honed the taste over time, and now I’d say that ketone esters taste like a robot’s ass. We can only imagine what they tasted like before.

Ketones have mostly been marketed as a before-and-during-exercise supplement, at least in the podcast ads I have heard. Take ketones, burn more fat at higher intensities, win the Tour de France, etc. However, a bunch of studies have shown limited to no acute benefit. For example, a 2017 study in Frontiers of Physiology found that pre-exercise ketone supplementation caused around a two percent performance decrease in 10 male professional cyclists doing a 50-minute time trial.

Perhaps there’s some protocol being used in the cycling peloton that improves acute performance, as the marketing claims indicate. Heck, Tom Evans reportedly took ketone esters on his way to winning Western States, so there must be some benefit for some athletes (or at least neutral impacts), possibly related to perceived effort. Anecdotally, when I tried ketones on a fatigued long run, the lights went out. Thankfully, I had my phone to call the Wuber (when my wife Megan drives to pick me up).

So perhaps it’s something else. Maybe all this ketone hype is because taking them improves recovery and hematological variables, confounding variables that are actually the driving force behind their use (maybe that even explains some of the success stories behind low carb, high fat nutrition approaches. I’d love to see the blood work!).

According to the review, after exercise, circulating ketone bodies are increased. However, any benefits athletes may see from a sustained increase are blunted in advanced athletes practicing good recovery nutrition. Ketone esters “may induce a unique physiological milieu to enhance post-exercise recovery and exercise adaptation as it allows to benefit from the potential beneficial effect of post-exercise ketosis in combination with other nutritional exercise recovery strategies (e.g., carbohydrate-protein recovery drink).” They had me at physiological milieu. Dr. Poffé says that his lab started ketone work in 2016 when “there was already some preliminary data showing that it could help riders during the Tour de France as a recovery aid.”

Mechanisms of Post-Exercise Ketones

I can’t emphasize enough how great this review article is, summarizing extremely uncertain science and studies. Before getting to the EPO mechanisms, let’s briefly touch on a bunch of other considerations. First, ketone bodies may cause epigenetic changes. For example, histone lysine β-hydroxybutylation could increase with ketone body increases, which may “increase transcription of genes involved in the adaptive response to exercise.” Across several different epigenetic mechanisms, it’s possible that ketone bodies could be a signal to the body to adapt to stimuli (which makes sense given their evolutionary role in exercise in energy-limited environments).

Second, ketones could “enhance the restoration of cellular energy status after exercise” while also blunting AMPK phosphorylation, which could enhance recovery due to its role in cellular stress or decrease adaptation due to its role in mitochondrial biogenesis. I love this one because that maybe-good, maybe-bad uncertainty regarding downregulation of AMPK points out just how little is known about the long-term consequences of post-exercise ketones, particularly in conjunction with other impacts.

Third, ketones alter g-receptor signaling, which “mediate cellular responses to a wide variety of external agents.” Fourth, ketones show anti-inflammation and anti-oxidation properties, which seems good at first glance but could theoretically cause long-term reductions in training adaptations since the inflammation response can spur adaptation. Fifth, ketones may influence neurotransmitter concentrations in the brain, which could profoundly impact perceived exertion (and possibly even mental health, though that’s a topic for another day).

The next cohort of potential adaptations are at the cutting edge of science but still theoretical. Ketones could increase muscle glycogen resynthesis, reduce protein degradation and enhance protein synthesis, spur angiogenesis that leads to more capillaries to supply blood to working muscles, induce favorable changes in muscle mitochondria, and improve sleep quality in athletes who are training hard. You can put those variables together with a 2019 study in the Journal of Physiology, where male athletes completed a three-week overload training block with six days a week of two-a-day training sessions, with one group having post-exercise ketones. That study found higher tolerated training load in the ketone group and improved performance. (The study was the subject of a Letter to the Editor disputing some of the conclusions.)

A 2023 study looked at a similar three-week overload block, validating the findings. They had 18 male athletes complete 10 training sessions per week, with one group taking post-exercise and pre-sleep ketones and the other taking a placebo. The ketone group “increased the number of capillary contacts and the capillary-to-fibre perimeter exchange index by 44 percent and 42 percent,” plus “substantially increased vascular endothelial growth factor and endothelial nitric oxide synthase expression both at the protein and at the mRNA level.” And the money finding: EPO concentrations in the ketone group increased by 26 percent. That study was eye-opening for the possible recovery and adaptation benefits of ketones, and it brings us back to the elephant in the room: potential hematological changes from increased EPO production.

Hematological Changes

In 2018, a study in the Diabetes Care journal found increasing levels of EPO after a ketone body infusion. The authors of the 2023 study that started this article cited this study as part of the impetus for their investigation (read their amazing summary here). We’re seeing similar findings in athletes in the 2023 studies, which found 20 percent and 26 percent increases in EPO production in the ketone groups relative to controls. But the science is not there to make a definitive conclusion.

In the title of this article, I promised uncertain science, and now we are deep in it. First, we don’t know how much this EPO change may impact performance. “Currently,” the review says, “it has not been identified if the observed changes in EPO post-exercise are indeed sufficient to induce an improvement in hemoglobin mass and oxygen transport capacity in humans, and whether these effects are additive to stimuli that are frequently used by athletes to increases EPO such as hypoxia.” It’s possible that these changes don’t correspond to performance benefits.

And get a load of this: “The precise physiological mechanism underlying ketone body-induced upregulation of EPO is currently unknown.” However, based on mouse models, the researchers theorize that it relates to H39K acetylation in kidney cells.

Are Ketones the Future?

There are tons of unanswered questions. How do these types of adaptations change over time? The longest study right now is a few weeks.

Do the processes change in female athletes? That’s one of my big concerns in making any recommendations since metabolic processes can vary based on gender. While more research is needed, Dr. Poffé indicates that past studies likely show that the results can be extrapolated to female athletes. “In a recent, unpublished study,” he says, “we observed that some effects are even more pronounced in females.”

How about aging athletes? Athletes of different levels, with different goals and backgrounds? What’s the right dosage and timing? Would the same responses happen at altitude? Should consumption be periodized? With similar studies, would other interventions lead to similar findings? Should ketones be banned altogether?

I don’t know the answers to those questions, and a lot more studies are needed before I make coaching recommendations other than “be careful” and “keep it simple.”

“Similar to most nutritional supplements,” Dr. Poffé says, “the long term effects (e.g. what occurs if you supplement for multiple years) are not known.” When athletes take ketones, he says instead of taking them chronically, to supplement “during periods of limited recovery opportunities,” like training camps. From a performance perspective, he advises to consider ketones when everything else is sorted out around training, nutrition, and recovery. They are “the final step,” not the first one.

In September, after reading the research, I dusted off that old package of ketones and opened up a serving for myself. Then I threw it in the trash because it seemed like a health hazard after all those years. I ordered a new package and started experimenting with them a couple days a week post-exercise. In October, at the Blue Sky Marathon, I closed the final four miles two minutes faster than last year to set a course record.

That probably had nothing to do with ketones, right? I’m no Olympian, but I train hard. And when looking back on the race and why I could finish so fast while feeling so good, I would be burying my head in the sand not to consider one of the only variables that changed.

I’m not sure what the future holds with post-exercise ketone supplementation. Maybe it’s all snake oil and placebo, with some studies that find physiological anomalies without a demonstration that it fundamentally alters performance trajectories, destined to be covering dust in the pantry of exercise physiology history.

Or maybe we’re seeing the dawn of a revolution in endurance training and performance.

 

The prospect of seeing one of athletics' biggest stars back on the track is growing stronger, with Jakob Ingebrigtsen reportedly targeting a return to competition later this summer following his recovery from Achilles tendon surgery.

According to comments made by his agent, Daniel Wessfeldt, in an interview with Norwegian media, the double Olympic champion could make his long-awaited comeback at one of three major European meetings in July. The leading options under consideration are the Monaco Diamond League on July 10, the Hungarian Athletics Grand Prix on July 14, and the London Diamond League on July 18.

For athletics fans, the possibility of Ingebrigtsen lining up in London would add another layer of excitement to an already highly anticipated Diamond League meeting. The Norwegian middle-distance sensation has become one of the sport's most dominant figures in recent years, collecting Olympic, world and European titles while consistently rewriting record books.

His 2026 campaign was put on hold after he underwent surgery on his Achilles tendon earlier this year, forcing him to focus on rehabilitation rather than competition. Since then, questions have surrounded when the 24-year-old would be ready to return to racing.

The latest update suggests that decision will largely depend on how his training progresses over the coming weeks. If recovery continues according to plan, July could mark the beginning of his return to elite competition ahead of the latter stages of the season.

A comeback at either Monaco, Budapest or London would immediately place Ingebrigtsen back among the sport's biggest storylines. Each meeting is renowned for producing world-class performances, and any appearance by the Norwegian would attract significant attention from fans eager to see how quickly he can regain top form after his injury setback.

While no final decision has been confirmed, the signs are increasingly positive. After months away from competition, Jakob Ingebrigtsen appears to be edging closer to a return, with London's Diamond League meeting emerging as one of the most intriguing possibilities on his road back to the track.

Should his recovery continue smoothly, athletics could soon welcome back one of its brightest and most influential stars.

What should have been the defining moment of Emad Bashir-Mohammed's young running career instead turned into one of the most talked-about controversies in American road racing this year.

The 23-year-old crossed the finish line first in the men's citizen's race at the prestigious Bolder Boulder 10K on Memorial Day in Colorado, stopping the clock at an impressive 29:50. His performance was not only a commanding victory but also one of the fastest winning times ever recorded in the event's long and celebrated history. Bashir-Mohammed finished eight seconds clear of his nearest challenger and appeared to have secured a breakthrough triumph.

For nearly two hours, he was the undisputed winner.

Then everything changed.

Race officials announced that Bashir-Mohammed had been disqualified after determining that he had started in the wrong wave. According to Bolder Boulder regulations, he had been assigned to the AA wave but lined up with the faster A wave, which began earlier. Event rules allow runners to move backward into a slower wave, but prohibit athletes from advancing into a faster one.

As a result, Bashir-Mohammed's victory was erased from the record books.

The citizen's title was subsequently awarded to Nickolas Scudder, who crossed the line second in 29:58. The promotion handed Scudder back-to-back citizen's race victories, while Bashir-Mohammed was left to grapple with the disappointment of losing a win he believed he had earned on the road.

The disqualification has since ignited widespread debate across the running community.

Bashir-Mohammed maintains that he did not intentionally violate the rules. He claims that after collecting his AA bib, he spoke with race personnel and was permitted to start with the A wave after presenting evidence of his recent performances. In a statement shared after the race, he expressed frustration over the decision, arguing that his goal was simply to compete against the strongest field available and produce the fastest time possible.

Race organizers, however, stood firmly behind their ruling. Officials stated that wave-assignment regulations are clearly communicated in pre-race information and reiterated during packet collection. They also noted that hundreds of participants are disqualified each year for moving into faster start groups, emphasizing that consistent enforcement is necessary to maintain fairness for all competitors.

The incident has divided opinion among runners and fans alike. Some believe the rules must be applied equally regardless of an athlete's finishing position, arguing that wave assignments are a fundamental part of race organization. Others feel the punishment is harsh, particularly if Bashir-Mohammed genuinely received approval to move up before the start.

What remains undisputed is the quality of his performance. On the roads of Boulder, Bashir-Mohammed demonstrated the fitness and speed required to outrun the field by a significant margin. Yet in road racing, crossing the finish line first is only part of the equation. Compliance with race regulations carries equal weight.

For Bashir-Mohammed, the day will be remembered as a painful lesson in the fine margins that can define elite competition. A remarkable run delivered a memorable victory, but a dispute over wave placement ultimately overshadowed the achievement, leaving behind a controversy that continues to fuel discussion throughout the running world.

A fast race, a costly administrative error, and a debate that may linger long after the finish-line tape has been packed away.

The men's 100 metres at the 2026 Rome Diamond League is shaping up to be one of the most anticipated sprint races of the season, with an exceptional field featuring some of the fastest men in the world.

Scheduled for Thursday, June 4, at the iconic Stadio Olimpico in Rome, the race will bring together reigning stars, established champions and emerging talents in a contest that promises fireworks from the moment the gun goes off.

Kenya's Ferdinand Omanyala headlines a world-class lineup that includes American sprint sensation Noah Lyles, Botswana's Olympic champion Letsile Tebogo, Jamaica's explosive Ackeem Blake, South Africa's ever-consistent Akani Simbine and Italy's hometown hero Lamont Marcell Jacobs. With personal bests ranging from 9.77 to 9.97 seconds, the field is packed with athletes capable of producing something special on the Diamond League stage.

Omanyala, the African record holder with a blistering personal best of 9.77 seconds, arrives in Rome eager to continue his strong early-season form and prove he can challenge the very best on the global circuit. The Kenyan star has built a reputation as one of the fastest starters in world sprinting and will be looking to make a statement against an elite field.

Standing in his way is world champion Noah Lyles, whose personal best of 9.79 seconds places him among the fastest athletes in history. The American remains one of the sport's biggest attractions and will be determined to add another Diamond League victory to his impressive résumé.

The race also marks a major test for Olympic champion Letsile Tebogo. The Botswanan star has rapidly become one of athletics' most exciting talents, while Ackeem Blake continues to establish himself as a serious contender on the international sprint scene.

Adding further intrigue is the presence of Italy's Lamont Marcell Jacobs. Competing on home soil, the Tokyo Olympic champion will enjoy passionate local support as he seeks to deliver a memorable performance in front of the Roman crowd.

South Africa's Akani Simbine, Cameroon's Emmanuel Eseme, Great Britain's Jeremiah Azu and rising American talent Jordan Anthony complete a field that boasts remarkable depth and quality.

Men's 100m Entry List – Rome Diamond League 2026

Ferdinand Omanyala (Kenya) – PB: 9.77

Noah Lyles (USA) – PB: 9.79

Lamont Marcell Jacobs (Italy) – PB: 9.80

Akani Simbine (South Africa) – PB: 9.82

Letsile Tebogo (Botswana) – PB: 9.86

Ackeem Blake (Jamaica) – PB: 9.88

Jordan Anthony (USA) – PB: 9.91

Emmanuel Eseme (Cameroon) – PB: 9.96

Jeremiah Azu (Great Britain) – PB: 9.97

With multiple national record holders, global champions and Olympic medal contenders sharing the same start line, the Rome Diamond League men's 100m could deliver one of the fastest races of the year. For sprint fans around the world, all eyes will be on Rome as a stellar cast battles for supremacy over athletics' blue-riband distance.

Audrey Werro announced her arrival as one of the early stars of the 2026 outdoor season with a commanding victory in the women’s 800 metres at the Rabat Diamond League, producing a performance that exceeded even her own expectations.

The Swiss middle-distance talent surged to victory in a brilliant 1:56.56, breaking the meeting record and delivering one of the fastest times recorded worldwide this season. In a race packed with quality, Werro displayed exceptional composure, confidence, and finishing strength to separate herself from the field and stamp her authority on the event.

What made the performance even more remarkable was the athlete's surprise at the level she had already reached so early in the campaign.

"I was not expecting such a strong start to the season," Werro admitted after the race.

The race unfolded at a relentless pace, but Werro remained perfectly positioned throughout. As the athletes approached the bell lap, she glanced at the clock and immediately sensed something special was within reach.

"When I saw the time at the bell, I felt really confident," she said. "I'm really happy with the Meeting Record and looking forward to the rest of the season."

Her confidence proved justified. Maintaining her rhythm over the final 400 metres, Werro powered down the home straight to secure the victory and rewrite the Rabat meeting record books in the process.

The performance sends an early warning to her rivals ahead of a season that promises major championships and high-profile Diamond League battles. Beyond the record-breaking time, Werro's display highlighted her growing maturity as a racer, combining tactical awareness with impressive speed and endurance.

With the outdoor season only beginning, the 1:56.56 clocking suggests that even faster times could be on the horizon. If Rabat is any indication, Audrey Werro may be poised for the biggest season of her career.

Her emphatic victory in Morocco was more than just another Diamond League win—it was a statement of intent from an athlete determined to challenge the world's best throughout 2026.

The city of Boston is set to welcome back one of its most celebrated champions as Kenya’s Sharon Lokedi headlines a world-class field for the 2026 B.A.A. 10K presented by Mass General Brigham Cancer Institute on June 21.

Fresh from another remarkable victory at the Boston Marathon in April, Lokedi returns to the streets of Boston and Cambridge carrying both momentum and confidence as she aims to defend the title she captured in dominant fashion last year.

The two-time Boston Marathon champion has developed a special connection with the historic race city. In 2025, she produced a course-record performance of 2:17:22 to win the Boston Marathon before returning this year to claim another victory in 2:18:51, the second-fastest winning time in the event’s storied history. Her success has cemented her status as one of the premier road runners in the world.

Lokedi will be making her first competitive appearance since her marathon triumph and arrives as the reigning B.A.A. 10K champion after clocking 31:39 over the challenging 6.2-mile course in 2025.

“Boston has become a very special place for me,” Lokedi said ahead of the race. “The atmosphere created by the fans and the community is unlike anywhere else. I’m excited to return and give everything I have to defend my title.”

The women’s race promises to be highly competitive. American Olympian Rachel Smith, who finished second at the Boston 5K in April, leads the domestic challenge. Kenya’s strong contingent includes African 10,000m champion Gladys Kwamboka, former B.A.A. 10K runner-up Stacy Ndiwa, and experienced road racer Viola Cheptoo. British Olympian Jessica Warner-Judd adds further international depth to a field packed with proven performers.

The men’s race is equally impressive, featuring elite athletes from 13 nations.

Ethiopia’s Dawit Seare enters as one of the leading contenders after capturing the 2025 Boston 5K title and bringing the fastest 10K personal best in the field at 27:21. Kenya will be represented by an accomplished group led by Alexander Mutiso, winner of the 2024 London Marathon and runner-up at last year’s New York City Marathon.

Patrick Kiprop also arrives in outstanding form after securing victory at the prestigious BolderBoulder 10K on Memorial Day, while Alex Masai returns looking to continue his strong record in Boston. Masai recently finished ninth at the Boston Marathon and has earned three top-ten finishes at the B.A.A. 10K.

Among the international stars making their mark is South Africa’s Adriaan Wildschutt, who makes his race debut after an impressive season highlighted by victory at the NYC Half Marathon in 59:30. Ethiopia’s Olympic bronze medallist Hagos Gebrhiwet adds further quality to the field, bringing a wealth of championship experience and previous success in Boston.

Canadian national 10K champion Andrew Alexander, two-time U.S. Olympian Hillary Bor, marathon standout Ryan Ford, and reigning USA 25K champion Andrew Colley complete a field stacked with talent and depth.

With defending champions, Olympic finalists, national champions and rising stars all converging on Boston, the 2026 B.A.A. 10K is shaping up to be one of the most competitive editions in recent memory. For Sharon Lokedi, however, the mission is simple: return to the city where she has repeatedly excelled and add another memorable chapter to her growing Boston legacy.