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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.

 

Some victories are measured by finish times. Others are defined by the obstacles overcome simply to reach the starting line.

For American Paralympic swimmer Ali Truwit, completing the New York City Marathon represented far more than covering 26.2 miles. It was the culmination of an extraordinary journey of survival, resilience, and unwavering determination that began with a life-altering shark attack just two years earlier.

On a crisp November morning in 2025, Truwit crossed the iconic finish line wearing a carbon-fibre running blade, fulfilling a promise she had made while recovering in a hospital bed after losing her lower left leg. The emotional milestone marked another remarkable chapter in one of the most inspiring comeback stories in modern sport.

The road to that unforgettable finish began only days after Truwit celebrated a major personal achievement. In May 2023, she completed her first marathon in Copenhagen alongside her mother. Just ten days later, while enjoying a graduation trip to Turks and Caicos with former Yale swimming teammate Sophie Pilkinton, tragedy struck.

While the pair were snorkelling, a shark attacked Truwit, severely injuring her left leg. Displaying remarkable courage, the two swam approximately 55 metres back to their boat, where Pilkinton—then a medical student—quickly applied a tourniquet that stopped the bleeding and ultimately saved Truwit's life.

Doctors were forced to amputate her lower left leg on her 23rd birthday.

Even in the darkest moments of recovery, Truwit's determination never disappeared. Reflecting on having recently completed her first marathon, she joked with one of the first responders that at least she had managed to run a marathon before the attack. The responder's simple but powerful reply would remain with her throughout rehabilitation: "You'll run another one."

Those words became a source of hope during the long and demanding road back.

Only weeks after surgery, Truwit began learning to walk on a prosthetic limb before gradually returning to the swimming pool. The process was anything but straightforward. The water that had once been her sanctuary became a source of painful memories, yet she refused to allow fear to define her future.

Her relentless work ethic soon produced extraordinary results.

Less than 16 months after the attack, Truwit represented the United States at the Paris 2024 Paralympic Games, producing a sensational performance to claim both silver and bronze medals. Standing on the Paralympic podium was a powerful reminder of how far she had come in such a short period, and she dedicated those achievements to everyone who had helped save her life.

Still, another dream remained unfinished.

The New York City Marathon carried deep personal significance. It was not merely another endurance event but a symbolic return to the city where her life had changed forever. On November 2, 2025, she lined up in Staten Island accompanied by 13 family members and close friends, all proudly representing her nonprofit foundation, Stronger Than You Think. Among them was Pilkinton, the friend whose quick thinking had preserved her life on that unforgettable day in the Caribbean.

Together, they covered every mile of the marathon before celebrating an emotional finish that Truwit later described as being "over the moon."

Completing a marathon on a carbon-fibre running blade presents challenges far beyond those faced by able-bodied runners. The prosthetic demands greater strength from the hips, core, and remaining leg while requiring exceptional balance, coordination, and endurance. Truwit's preparation combined months of disciplined training, patience, and mental resilience as she effectively taught herself how to run again.

Her story extends well beyond medals and marathon finishes.

Inspired by her own recovery, Truwit founded Stronger Than You Think, a nonprofit organisation dedicated to helping individuals overcome physical and financial barriers following limb loss. Recognising that sports prosthetics can cost tens of thousands of dollars and are often not covered by insurance, the foundation provides financial assistance for prosthetic devices, supports water-safety education, and promotes opportunities within Paralympic sport.

The organisation has already helped provide more than 11 prosthetic limbs, delivered nearly $200,000 in direct support, and funded over 4,000 hours of water-safety lessons benefiting more than 700 young people.

Throughout her journey, Truwit has remained refreshingly honest about the emotional challenges that continue to accompany recovery. She has openly acknowledged that healing is an ongoing process and that grief can still come in waves. Rather than portraying an effortless comeback, she has demonstrated that resilience is built through persistence, even on the hardest days.

Her remarkable transformation resonates far beyond elite sport. While few people will ever experience the trauma she endured, countless runners and athletes understand the frustration of injury, disappointment, or rebuilding after adversity. Truwit's journey serves as a powerful reminder that recovery is rarely linear and that courage is often measured by the willingness to keep moving forward despite uncertainty.

Now looking ahead to the Los Angeles 2028 Paralympic Games, Truwit continues to redefine what is possible. She is no longer known simply as the swimmer who survived a shark attack. She has become a Paralympic medallist, marathon finisher, advocate, and symbol of resilience whose story continues to inspire athletes around the world.

Her journey proves that while life can change in an instant, so too can the strength of the human spirit. Sometimes the greatest triumph is not returning to the person you once were, but discovering someone even stronger than you ever imagined possible.

Sprint and hurdles superstar Sydney McLaughlin-Levrone has entered an exciting new chapter in her remarkable life, welcoming her first child with husband Andre Levrone. The four-time Olympic champion and women's 400m hurdles world record holder announced the birth of their daughter, Savannah Michelle Levrone, who was born on Sunday, July 12, 2026.

The couple shared the joyful news with an emotional message celebrating the arrival of their daughter and expressing gratitude to everyone who supported them throughout the pregnancy. Sydney described Savannah as "our blessing and our joy," while expressing excitement and faith for the future that lies ahead for their growing family.

The announcement marks a deeply personal milestone for one of the most accomplished athletes of her generation. Renowned for redefining the women's 400m hurdles through a succession of record-breaking performances, McLaughlin-Levrone now embraces a new role beyond the track as a mother.

The timing of the announcement adds another layer of significance. Just days earlier, Sydney reflected on the 10th anniversary of qualifying for her first Olympic Games at only 16 years old—a breakthrough that launched one of the most decorated careers in modern athletics. Ten years later, her journey has come full circle with another life-changing milestone, underscoring that her greatest moments continue to extend beyond sporting success.

The arrival of Savannah Michelle Levrone has been met with an outpouring of congratulations from athletes, fans, and the wider sporting community, who have celebrated the couple as they begin this new chapter together. As Sydney McLaughlin-Levrone steps into motherhood, the athletics world will undoubtedly continue to follow her inspiring journey—both on and off the track.

Ethiopia's Tsige Gebreselama produced one of the standout road running performances of the season on Sunday, storming to victory at the prestigious Boilermaker Road Race 15K in Utica, New York, with a sensational course record of 47:29.

From the opening kilometers, Gebreselama controlled the race with remarkable composure and precision, maintaining a relentless pace that ultimately erased the previous course record and secured one of the fastest performances ever recorded on the historic course. Her commanding display further reinforced her reputation as one of the world's leading road and distance runners.

The Ethiopian celebration continued as Melknat Wudu crossed the finish line in second place in 47:44, completing a dominant one-two finish for her country. Kenya's Priscah Cherono claimed third in 48:14 after a determined effort, rounding out a world-class podium in a race featuring some of the finest distance runners on the international circuit.

The battle behind the podium remained fiercely competitive. Kenya's Everlyn Kemboi finished fourth in 48:28, narrowly ahead of compatriot Selah Busienei, who clocked 48:31 for fifth. Ethiopia's Netsanet Desta and Alem Nigus Tsadik followed in sixth and seventh respectively, while Kenya's Mercy Cherono secured eighth place.

American athletes also delivered encouraging performances on home roads. Veteran Stephanie Bruce finished ninth in 50:40, with Jackie Gaughan completing the top ten in 51:02 to cap a strong showing for the host nation.

Boilermaker Road Race 15K – Women's Top 10 Results

1. Tsige Gebreselama (Ethiopia) – 47:29 (Course Record)

2. Melknat Wudu (Ethiopia) – 47:44

3. Priscah Cherono (Kenya) – 48:14

4. Everlyn Kemboi (Kenya) – 48:28

5. Selah Busienei (Kenya) – 48:31

6. Netsanet Desta (Ethiopia) – 48:46

7. Alem Nigus Tsadik (Ethiopia) – 48:48

8. Mercy Cherono (Kenya) – 50:23

9. Stephanie Bruce (United States) – 50:40

10. Jackie Gaughan (United States) – 51:02

The women's race combined exceptional depth with remarkable speed, as several athletes broke the 49-minute barrier in a contest that showcased the global strength of elite road running. Gebreselama's record-breaking run now stands as a new benchmark in the rich history of the Boilermaker 15K, adding another memorable chapter to one of the United States' most celebrated road races.

Kenya's Alex Matata delivered a sensational performance to claim the men's title at the prestigious Boilermaker Road Race 15K in Utica, New York, producing a dominant run that underlined his growing reputation as one of the world's finest road racers.

Matata surged to victory in an outstanding time of 42:24, mastering the demanding course with a display of strength, speed, and tactical brilliance. His commanding performance secured a memorable triumph in one of the United States' most celebrated road races, adding another significant international victory to his career.

Kenya's success was further highlighted by Kiprono Sitonik, who produced an equally impressive run to finish second in 42:53, completing a remarkable one-two finish for the East African nation. South Africa's Adam Lipschitz rounded out the podium after clocking 43:14 to claim third place following a determined effort.

The race featured a highly competitive international field, with American athletes Reid Buchanan and Hillary Bor finishing fourth and fifth respectively, while another Kenyan, Victor Shitsama, added to his country's strong showing by taking sixth place.

Matata's victory once again showcased Kenya's enduring strength in global road racing, as its athletes continued to dominate major international competitions through exceptional endurance, tactical awareness, and relentless finishing speed. His performance in Utica not only thrilled the spectators lining the streets but also reinforced the depth of Kenyan distance running on the world stage.

Men's Top 10 Results – Boilermaker Road Race 15K

1. Alex Matata (Kenya) – 42:24

2. Kiprono Sitonik (Kenya) – 42:53

3. Adam Lipschitz (South Africa) – 43:14

4. Reid Buchanan (United States) – 43:38

5. Hillary Bor (United States) – 43:40

6. Victor Shitsama (Kenya) – 44:02

7. Futsum Zienasellassie (United States) – 44:32

8. Charlie Sweeney (United States) – 44:37

9. Sam Lawler (United States) – 44:54

10. Tyler Berg (United States) – 45:08

With another major road racing title added to his résumé, Alex Matata continued his impressive 2026 campaign while reinforcing his status as one of the leading names on the international road racing circuit. The Boilermaker 15K once again delivered a high-quality contest, with athletes from across the globe producing memorable performances in one of the United States' most prestigious road races.

Eliud Kipchoge's remarkable World Tour continued on Brazilian soil as the Kenyan marathon icon completed the New Balance 42K Porto Alegre Marathon, crossing the finish line in 2:18:39 to place 12th overall during the second stop of his ambitious seven-continent global running tour.

Competing against a strong international field, the two-time Olympic marathon champion displayed the resilience and determination that have defined his legendary career. While the result was not among the victories that have made him one of the greatest marathon runners in history, Kipchoge once again demonstrated the unwavering commitment that continues to inspire athletes and fans across the globe.

Morocco's Zineddine Ouria claimed victory in a superb 2:08:49, with Kipchoge finishing 9 minutes and 50 seconds behind the race winner after navigating the demanding course in Porto Alegre.

Kipchoge began the race with controlled and confident pacing, reaching 5km in 15:34 before passing the halfway mark in 1:05:07. As the race entered its decisive stages, the pace gradually slowed, but the veteran marathoner pressed on with characteristic determination, completing the 42.195-kilometre challenge in 2:18:39.

For many, the story will be told through the finishing position. But for those who truly understand greatness, this journey is about far more than medals, records, or podium finishes. Kipchoge's World Tour is a celebration of the sport itself—an opportunity to connect with runners across every continent, inspire the next generation, and continue living by the philosophy that has become synonymous with his career: "No Human Is Limited."

The Brazilian appearance also carried added significance, coming shortly after Kipchoge was permanently honoured in Porto Alegre with his footprints unveiled at the entrance of Parque Harmonia—a lasting tribute to his extraordinary impact on distance running and his enduring legacy in the sport.

Once a champion. Forever an inspiration. Legends do not stop inspiring when the victories become fewer; they inspire because they never stop showing up. Through every stride, every finish line, and every challenge embraced, Kipchoge continues to prove that true greatness is measured not only by what an athlete wins, but by the lives they touch along the way.

With the second stop of his World Tour now complete, Kipchoge will turn his attention to the next chapter of his global adventure when he lines up at the Melbourne Marathon in Australia this October. Wherever he races, millions will once again follow the journey of a man whose legacy extends far beyond the stopwatch.