Veech Ketone Ester can work from the first bottle. How well depends entirely on how you use it.
More human research exists on this molecule than on every other exogenous ketone combined. It has improved late-race power, raised aerobic capacity across a training block, and grown the capillary network feeding working muscle. It has also been studied doing nothing at all — in protocols that asked it to do something it was never going to do.
The difference is protocol. That's what this page is about.
100 MILES IN UNDER 24 HOURS · NO CARBOHYDRATE · VKE AND ELECTROLYTES ONLY
Do ketone esters improve endurance performance?
Yes — but the protocol matters. Human Veech Ketone Ester trials include improved endurance performance, null results and one negative short-duration protocol. The clearest positive evidence appears in prolonged exercise, in specific co-ingestion protocols, and in repeated post-training use across training blocks.
WHO ALREADY USES IT
The most scrutinised athletes on earth settled this already.
Professional cycling tests everything and keeps almost nothing. Ketone esters have been in the peloton for years, through a doping-adjacent press cycle and a UCI advisory, and the teams still use them.
KetoneAid is an advisory partner to two WorldTour teams, supplying VKE and protocol optimization support.
21
STAGES IN THREE WEEKS — THE PUREST TEST OF ENDURANCE, RECOVERY & REPEAT THERE IS
2026 TOUR DE FRANCEMARK CAVENDISHXDS ASTANASOUDAL QUICK-STEP · FINISH LINE
This isn't scientific evidence. It's real world proof from those who have done their homework.
WHAT IT DOES ON THE DAY
Yes, it works in a
single session.
Three human cycling trials show why protocol matters. Cox and Poffé found benefits after prolonged work; the WorldTour study found a 3.1% benefit in the opening 8-minute effort of a much longer stage simulation.
30-MIN TT AFTER AN HOUR'S WORK
Ketone ester improved time-trial performance by about 2%.
+2%30-MINUTE TIME-TRIAL PERFORMANCE
The original Oxford work, in elite athletes, with the ester taken alongside carbohydrate after 60 minutes at 75% of peak power.
Cox et al. 2016 · Cell MetabolismSEE STUDY ↓END OF A 3-HOUR RACE
With bicarbonate alongside it, mean power rose 5% in the closing time trial.
+5%MEAN POWER, 15-MIN TT AFTER 3 HOURSKE ALONE AND BICARBONATE ALONE DID NOTHING
Bicarbonate is the buffer your blood uses to soak up acid — the same compound as baking soda, and a long-standing endurance supplement in its own right. Neither ingredient worked without the other.
Poffé et al. 2021 · MSSE · 9 trained cyclistsSEE STUDY ↓WORLDTOUR PROFESSIONALS
In WorldTour cyclists, power improved in the opening phase of a simulated stage.
+3.1%FIRST 8-MINUTE TIME TRIAL · ABOVE THE SMALLEST WORTHWHILE CHANGE
Monoester with bicarbonate, in actual professional riders rather than recreational athletes.
Prevent mental fatigue. During long efforts, when your focus begins to fade and you drift off pace without noticing, VKE brings you back.
HEAT + PHYSICAL LOAD
Endurance-trained men lasted 27% longer in the final time-to-exhaustion test after prolonged loaded exercise in the heat.
27% longerTIME TO EXHAUSTION · 8.9 MIN VS 7.0 MIN1-BACK TARGET ACCURACY +8.9% VS CARBOHYDRATE
17 endurance-trained males, 90 minutes of loaded treadmill work at 34°C, then a high-intensity test to exhaustion. The 1-back task asks you to track a running sequence while still working — the kind of attention a long effort demands. Both conditions also contained caffeine, so the study tested VKE + caffeine versus carbohydrate + caffeine, not VKE alone.
Lints et al. 2026 · PMID 42460838REACTION UNDER STRESS
Split-second accuracy dropped far less than it did on placebo.
62%SMALLER DROP IN SPLIT-SECOND DECISION ACCURACY1.3% DROP WITH VKE VS 3.4% ON PLACEBO
Accuracy still slipped — it just slipped a lot less. Holding your level as the effort bites is the realistic goal.
Quinones et al. 2022 · PMID 36297060
★★★★★
I use this before sparring for kickboxing. I found it definitely increases my aerobic capacity and how long I can last in multiple rounds. I am also using this as a mental boost and for clarity for studying and intense exams. I tried ketone salts before, and they are completely obsolete compared to this.
— CALEB
★★★★★
Wow…I barely trained for my recent half marathon and ended up breaking my PR from 11 years ago when I called myself a runner. I was so focused the whole race. The energy never stopped coming.
— JOHN FERRARO
There's a third strand: in ultra-endurance exercise, ketone ester intake raised circulating dopamine and was associated with maintained mental alertness. Your brain runs on roughly a fifth of your energy budget and oxidizes D-BHB directly — which is the same reason VKE shows up in the cognitive research at all.
— ISABELLE RUNOLFSDOTTIR, VERIFIED CUSTOMERPICTURED: ANTHONY KUNKEL
2× USA ULTRA RUNNING CHAMPION
★★★★★
I am a 65 year old cyclist and this is absolutely amazing!! It increases focus which is a big part of performance, but on longer climbs and rides, I feel fresher and have power and energy in reserve. I also noticed that my legs need less recovery time. Substantially less.
— TONY GILLILAND
★★★★★
Used for 70.3. Kept me constant, didn't run low on energy, combined with carbs.
— S C., HALF IRONMAN
★★★★★
This is a very good product for cycling, with very good results for a long day race, it also help me to increase my vo2 max, very good for recovery after a race and also very good recovery for next day race…
— DARIEN
CUSTOMER TESTIMONIALS. INDIVIDUAL EXPERIENCES VARY AND ARE NOT RESEARCH OUTCOMES.
FOR FAT-ADAPTED ATHLETES
The fuel that doesn't require carbohydrate.
Fat-adapted athletes can hit a ceiling: at higher intensities, fat oxidation alone may not supply energy quickly enough to sustain output — and athletes deliberately restricting carbohydrate may not want to add carbohydrate simply to increase available fuel. D-BHB is the third option: another oxidizable substrate that adds no carbohydrate.
Emil Igersalv
100 MILES IN UNDER 24 HOURS · NO CARBOHYDRATE
Emil ran 100 miles in under 24 hours taking no carbohydrate at all — only Veech Ketone Ester and electrolytes. It demonstrates that a very long endurance effort can be completed using a deliberately carbohydrate-free strategy that includes VKE — but it does not establish that carbohydrate is unnecessary for endurance athletes generally. Endogenous glycogen and body fat were still supplying energy throughout.
PODCAST INTERVIEW — LINK PENDING
Anthony Kunkel
2× USA ULTRA RUNNING CHAMPION · USATF 50-MILE AND 100K
Kunkel has built a career on low-carbohydrate endurance, and is one of the sport's most-studied practitioners of it. Fat-adapted racing is exactly the setting where a second fast fuel earns its place — the intensity ceiling that fat alone imposes is the whole problem.
PICTURED ABOVE
THE PART MOST PEOPLE GET WRONG
It depends how you use it.
The same molecule, in the same lab, has produced a 5% gain and a 1.5% loss. That isn't a contradiction — it's the clearest evidence there is that protocol decides the outcome. Here's what the trials actually teach.
DO
Use it for efforts lasting an hour or more
The acute gains came in prolonged events — after an hour of steady work, at the end of three hours, or across a simulated stage. Duration of the event matters more than where in it you measure.
COX 2016 · POFFÉ 2021 · IJSNEM 2024
DON'T
Don't dose it for a short, flat-out effort
In a high-intensity 30-minute cycling time trial performed with blood D-BHB around 3–4 mM, mean power was about 1.5% lower in the ketone conditions. Neutralizing the acid-base disturbance with bicarbonate did not rescue it.
POFFÉ, WYNS ET AL. 2021 · PMID 33196605
KNOW
Bicarbonate changed the result in the lab
The ester transiently lowers blood pH and bicarbonate. Replacing that buffer is what turned a null result into a 5% power gain in one trial. We're reporting what the research did, not recommending you add bicarbonate — it has its own tolerance issues and belongs in a conversation with your coach.
POFFÉ ET AL. 2021 · PMID 32735112
DON'T
Never take your first dose on race day
This is the single most common mistake. Taste, volume and GI response are individual, and race day is the worst possible moment to discover yours. Train with it first, every time.
DO
Use it through the training block
This is our actual recommendation, and where the evidence is strongest: after sessions and before sleep, week after week. The next section is why.
SEE THE LONG GAME BELOW
DON'T
More is not better
Larger doses mean a larger acid load, more GI risk, and in the short-TT study, worse performance. The failed protocols in the literature are mostly big single doses at the wrong moment.
Good on day one. Considerably better by week eight.
Most endurance supplements are evaluated as race-day aids. VKE is unusual because some of its strongest evidence comes from what happens after training and across repeated training blocks.
A single session is a stimulus. What you become is built from how much quality work you absorb and how much of it converts into adaptation. This is the part of the research nobody markets, and it's the part we'd stake the company on.
ONE SESSIONUseful
+2% time-trial performance
+5% late-race power with bicarbonate
Power in the opening phase of a stage
Fuel without carbohydrate
then
EIGHT WEEKS OF SESSIONSA different engine
VO2peak +6% beyond training alone
30-min time-trial power +4%
Sustainable training load +15%
Late-session power +15%
Capillary contacts +44%
Mitochondrial adaptations amplified
In all of those protocols VKE was taken after training and before sleep — not as a pre-workout. The gains showed up in what the training built, not in how the session felt.
Fuel the session. Then let it build the athlete.
THE MOLECULE MATTERS MORE THAN THE CATEGORY
Overwhelming evidence for VKE. No other ketone comes close.
“Exogenous ketones” is a category, but different ketones have different results. Monoesters, diesters, salts and precursors reach very different blood D-BHB levels — yet headlines and reviews routinely average them together. VKE has its own negative protocol, documented above. What it doesn't have is a substitute's evidence base.
Racemic 1,3-butanediol
In a 2019 trial using racemic R,S-1,3-butanediol — a precursor, and a different preparation from current commercial products — blood D-BHB reached only about 0.44–0.79 mM during exercise, a fraction of what the ester produces. Five of nine participants reported moderate to severe GI symptoms.
Acetoacetate diester
The famous “ketones made cyclists slower” study. Professional riders were about 2% slower over 31km, with frequent and severe GI distress. A different molecule, and the published commentary attributes the decrement to the GI distress rather than to ketosis.
Ketone salts
At a matched dose, salts peaked at 1.0 mM against the ester's 2.8 mM, and arrive roughly half as the L-BHB isoform the body handles poorly.
Veech Ketone Ester
The molecule in Cox 2016, both Poffé 2021 trials, the overload studies, the eight-week training study and the WorldTour work. When people cite “the ketone research”, this is the research they are citing.
Pooled analyses that average these together tell you about the average of four different things. They don't tell you about any of them.
WHERE THIS APPLIES
Where a second fuel
actually helps.
01
Long races and big days out
Where the last hour decides it and carbohydrate alone has stopped being enough.
02
Multi-day efforts and back-to-backs
When tomorrow's performance depends on how well tonight goes.
03
Build, recover, repeat
Train hard, repair stronger, go again. Week after week.
Overwhelmingly positive results. The null and negative outcomes are cautionary protocol tales, and they're here because they're the ones that teach you how to use it.
Elite athletes: about 2% further in a 30-minute time trial.
Cox et al. 2016 · Cell Metabolism · University of Oxford
Elite athletes · ester taken with carbohydrate
VIEW STUDY DETAILS +
PROTOCOL The foundational human performance study on the monoester. Athletes completed a 30-minute time trial after 60 minutes at 75% of peak power, having ingested the ketone ester alongside carbohydrate.
WHAT HAPPENED
Time-trial distance improved by about 2% versus control.
Nutritional ketosis altered fuel preference during exercise, sparing carbohydrate.
Muscle glycogen use and blood lactate were lower.
WHY IT MATTERS
2% is a large margin in a trained field.
The effort was already an hour old when the time trial began — the condition every later positive result shares.
CONTEXT: Small elite sample under laboratory conditions, and later work has not always reproduced it in different protocols — which is the argument of this page rather than an objection to it. PMID 27475046 — PubMed
End of a 3-hour race: 5% higher mean power — but only with bicarbonate.
Poffé et al. 2021 · MSSE 53(2):431–441 · KU Leuven
9 well-trained cyclists · four conditions
VIEW STUDY DETAILS +
PROTOCOL Double-blind randomized crossover. Nine well-trained male cyclists completed a 3-hour intermittent simulated race, a 15-minute time trial and an all-out sprint, taking 60g of carbohydrate per hour throughout. Four conditions: placebo, ketone ester, bicarbonate, or ketone ester plus bicarbonate.
WHAT HAPPENED
Mean power in the time trial was about 255 W in the ester, bicarbonate and control conditions alike.
With ester and bicarbonate together it was 5% higher (P = 0.02 versus control).
The ester alone dropped blood pH from 7.43 to 7.36 and bicarbonate from 25.5 to 20.5 mM.
No difference in gastrointestinal symptoms between conditions.
WHY IT MATTERS
It isolates the mechanism: the acid load was masking the fuel benefit, and replacing the buffer revealed it.
It explains why several earlier acute studies found nothing.
CONTEXT: Nine trained male cyclists. The benefit appeared when blood ketone levels had already fallen back toward baseline, so the authors are careful about attributing it to ketones alone. Bicarbonate supplementation has its own tolerance considerations. PMID 32735112 — PubMed
WorldTour professionals: improved power in the opening phase of a simulated stage.
IJSNEM 2024;34(1) · WorldTour cyclists
Ketone monoester with bicarbonate co-ingestion
VIEW STUDY DETAILS +
PROTOCOL Professional WorldTour cyclists completed a simulated road-cycling stage with repeated time-trial efforts, receiving ketone monoester with bicarbonate or placebo.
WHAT HAPPENED
Mean power in the first 8-minute time trial improved by 3.1%, exceeding the smallest worthwhile change.
The effect was in the initial phase of the stage rather than the later efforts.
WHY IT MATTERS
Actual WorldTour professionals, not recreational athletes — the population everyone argues about.
It supports the bicarbonate co-ingestion finding in a field setting.
CONTEXT: Small professional sample. Benefits were not seen in the later repeated efforts, and the bicarbonate is part of what was tested. International Journal of Sport Nutrition and Exercise Metabolism, 2024;34(1).
The warning: in a short flat-out time trial, ketosis reduced power by about 1.5%.
Poffé, Wyns et al. 2021 · MSSE 53(5):1068–1078
Well-trained cyclists · 30-min TT with and without bicarbonate
VIEW STUDY DETAILS +
PROTOCOL The same group testing whether raising blood ketones helps when the acid load is neutralised. A 60-minute warm-up at low-to-moderate intensity including several harder efforts, then a 30-minute simulated time trial and an all-out sprint, under placebo, ketone ester, bicarbonate, or both.
WHAT HAPPENED
Mean power in the 30-minute time trial was about 1.5% lower in the ketone conditions, with blood D-BHB around 3–4 mM.
Bicarbonate did not rescue it — hence the title, independent of bicarbonate supplementation.
Sprint time to exhaustion was unchanged across all conditions.
WHY IT MATTERS
This is the single most useful result on the page for deciding when not to use it.
The authors concluded the effect was specifically unfavourable for short, high-intensity endurance exercise.
Same molecule, same lab, opposite result from the 3-hour protocol. Protocol is the variable.
CONTEXT: Well-trained male cyclists. Read alongside the 3-hour study rather than instead of it — together they define the window where acute use makes sense. PMID 33196605 — PubMed
Eight weeks: greater aerobic gains than the same training alone.
Robberechts et al. 2026 · Journal of Physiology
28 trained males · post-exercise and pre-sleep dosing
VIEW STUDY DETAILS +
PROTOCOL Twenty-eight trained males completed eight weeks of supervised cycling. Fourteen took 25g of the monoester immediately after each session and again before sleep; fourteen took an isocaloric placebo.
WHAT HAPPENED
Relative VO2peak improved 12% from baseline with VKE versus 6% in control — an additional 6%.
30-minute time-trial performance was 4% higher: 302 ± 28 W versus 291 ± 27 W.
Mitochondrial adaptations to training were amplified.
WHY IT MATTERS
The time-trial gain came from training with it for eight weeks, not from drinking it beforehand.
It is the largest and longest performance study on the molecule.
CONTEXT: Trained males only, 14 per group, supervised laboratory programme. Journal of Physiology, doi 10.1113/JP290315.
Overload block: 15% more late-session power and 15% more sustainable training load.
Poffé et al. 2019 · Journal of Physiology
18 fit males · 3 weeks, two sessions daily
VIEW STUDY DETAILS +
PROTOCOL Three weeks of deliberately excessive cycling designed to induce non-functional overreaching. Nine received a ketone ester after each session and before sleep; nine received a control drink.
WHAT HAPPENED
Power in the final 30 minutes of a 2-hour session was 15% higher with VKE.
Sustainable training load in week 3 was also 15% higher.
The rise in nocturnal adrenaline and noradrenaline was inhibited.
WHY IT MATTERS
Late in a long session is where training quality normally collapses.
Absorbing more load is the input to adaptation.
CONTEXT: Nine per group, fit males, a load built to cause overreaching. Part of the effect may relate to the difference in energy balance between groups. PMID 31039280 — PubMed
Overload block: capillary contacts up 44%, circulating EPO up about 25%.
Poffé et al. 2023 · Journal of Physiology
18 fit males · muscle biopsies
VIEW STUDY DETAILS +
PROTOCOL Three weeks of endurance overload at ten sessions per week. Nine received 25g of ketone ester after each session and 30 minutes before sleep; nine received an isocaloric control. Vastus lateralis biopsies before and after.
WHAT HAPPENED
Capillary contacts increased 44% with VKE and not in control.
The capillary-to-fibre perimeter exchange index increased 42%.
Serum EPO rose about 25%; VEGF and eNOS also increased in muscle.
WHY IT MATTERS
More capillary contact per fibre shortens the delivery distance for oxygen into working muscle.
Heavy overload normally blunts capillary growth. Here it didn't.
CONTEXT: Nine per group, fit males. Measures of muscle capillarisation and circulating EPO, not clinical outcomes. PMID 37062892 — PubMed
Other molecules: the diester decrement, and the butanediol that barely raised ketones.
Leckey et al. 2017 · Shaw et al. 2019
Not the Veech monoester
VIEW STUDY DETAILS +
PROTOCOL Leckey and colleagues gave ten elite male cyclists a 1,3-butanediol acetoacetate diester at 250mg per kg before a ~31km simulated championship time trial. Shaw and colleagues used racemic R,S-1,3-butanediol, a ketone precursor rather than an ester, and a different preparation from current commercial butanediol products.
WHAT HAPPENED
Leckey: performance was about 2% worse than control, with frequent and severe gastrointestinal distress.
Shaw: blood D-BHB reached only about 0.44–0.79 mM during exercise, and five of nine participants reported moderate to severe GI symptoms.
WHY IT MATTERS
Both are routinely pooled with monoester data in reviews and headlines, which is how “ketones don't work” gets written.
A compound that reaches 0.5 mM is not testing the same thing as one that reaches 3 mM.
The published commentary on Leckey attributes the decrement to the GI distress rather than to ketosis.
CONTEXT: We include these because they are the studies most often cited against ketones, and because the molecule distinction only counts for something if we're willing to show the papers. Leckey PMID 29109686 — PubMed
MORE — ALSO IN THE RECORD
The trials above are the ones that shape how we tell people to use it. These are the rest of the monoester endurance literature, including the nulls. We'd rather you saw the whole file.
10-km running · null
An hour of submaximal running then a 10-km all-out test. No benefit. Blood βHB stayed under 1.5 mM during exercise, and the effort was short and carbohydrate-dependent. Evans, McSwiney, Brady & Egan 2019 · MSSE 51:2506–2515
Glycogen sparing · null
12 highly trained cyclists, 3-hour simulated race with 60g carbohydrate per hour. VKE did not spare muscle glycogen and did not change final-stage performance. The glycogen-sparing theory largely died here. Poffé, Ramaekers, Bogaerts & Hespel 2020 · PMID 32407242
Altitude · mixed
Exogenous ketosis increased blood and muscle oxygenation in hypoxia, but did not improve performance there. Poffé et al. 2021 · Am J Physiol Regul Integr Comp Physiol 321:R844–R857
Ultra-endurance · alertness
18 recreational runners attempting 60–100km. VKE maintained mental alertness and roughly doubled circulating dopamine during the run versus control. Poffé et al. · J Appl Physiol · PMID 37141424
Intermittent running · cognition
Cognitive performance after ketone ester ingestion during intermittent running. Evans & Egan 2018 · MSSE 50:2330–2338
Fluid balance · mechanism
Exogenous ketosis suppressed diuresis and atrial natriuretic peptide during exercise. Robberechts, Poffé & Hespel 2022 · J Appl Physiol 133:449–460
1,3-butanediol · 2026 · null NOT VKE
Nine male athletes adapted to a ketogenic diet for at least a year took 60g carbohydrate alone, or 60g carbohydrate plus 0.5g per kg of 1,3-butanediol, before 60 minutes of steady-state cycling and a 16.1-km time trial. Butanediol raised BHB to about 1.69 mM after exercise, but time-trial performance was not significantly different. Raising blood BHB with a precursor did not automatically produce a performance benefit. Small exploratory study (n=9); the authors state the data show no detectable ergogenic effect under these conditions and do not exclude smaller effects. This was a 1,3-butanediol study, not a Veech Ketone Ester study.Carpenter, Brouner & Spendiff 2026 · Nutrients 18(14):2388 · PMID 42514457
Acid-base · caution
Nutritional ketoacidosis during incremental exercise in healthy athletes — the work that first flagged the acid load now central to the protocol above. Dearlove, Faull, Rolls, Clarke & Cox 2019 · Front Physiol 10:290
On running specifically: direct running evidence is more limited, and the one 10-km trial was null. The strongest positive acute and training-adaptation evidence currently comes from cycling.
QUESTIONS PEOPLE ACTUALLY ASK
Ketones and endurance
Veech Ketone Ester is a food. Nothing on this page is intended to diagnose, treat, cure or prevent any disease, and nothing here is medical advice. Research findings described here are measured outcomes from controlled trials in specific participant groups under specific protocols, not expected results for any individual. Bicarbonate co-ingestion has its own tolerance considerations and is not part of our standard recommendation. Our Veech Ketone Ester molecule is manufactured in the United States.
Does VKE work the first time I use it?
Yes, under the right conditions.
Ketone ester improved 30-minute time-trial performance by about 2% in elite athletes, raised mean power 5% at the end of a 3-hour race when paired with bicarbonate, and improved opening-phase power in WorldTour professionals.
The conditions that matter are effort length and dose. Long or late efforts respond. Short flat-out efforts don't, and can go the other way.
Then it keeps improving. Eight weeks of training with it produced an additional 6% VO2peak gain over the same training alone — which is a bigger number than anything a single bottle will do.
Should I take it before a race?
Possibly, depending on the event and the protocol.
Positive acute studies have used different conditions, and some of the strongest results involved co-ingestion with carbohydrate or bicarbonate. Bicarbonate has its own dosing and tolerance considerations, so we don't recommend adding it solely from reading one study.
In a high-intensity 30-minute time trial, mean power was about 1.5% lower in the ketone conditions — so short, hard efforts are the weakest case.
Never use VKE for the first time on race day. Taste, volume and individual GI response need to be sorted in training, not at the start line.
Is more better?
No, and this is where most bad experiences come from.
Bigger doses mean a bigger acid load, more GI risk and no extra benefit. The failed protocols in the literature are largely big single doses at the wrong moment in the wrong kind of effort.
Because they asked different questions, and a few of them asked about a different molecule.
The monoester trials themselves produced positive, null and negative results depending on exercise protocol, dosing, carbohydrate intake and acid-base conditions. That isn't contradiction, it's dose-response and context.
Reviews that average all of it together — including 1,3-butanediol trials that reached under 1 mM of D-BHB — produce a headline that describes none of the individual studies.
Can I use it without carbohydrate?
Yes, and it's one of the more interesting uses.
Fat-adapted athletes can hit a ceiling because at higher intensities fat oxidation alone may not supply energy quickly enough. D-BHB is another oxidizable substrate that adds no carbohydrate.
Emil Igersalv ran 100 miles in under 24 hours on VKE and electrolytes alone, with no carbohydrate at all.
Why do WorldTour teams use it?
Mostly for recovery between stages, which is exactly where the strongest evidence sits.
A grand tour is the recover-and-repeat problem in its purest form: perform, recover, do it again tomorrow, twenty-one times. KetoneAid supplies and advises Soudal Quick-Step and XDS Astana.
Do exogenous ketones improve endurance?
“Exogenous ketones” is a category, but different ketones have different results.
Studies have tested ketone monoesters, other esters, ketone salts and ketone precursors, with different blood D-BHB responses and different results. The endurance evidence has to be interpreted molecule by molecule.
The strongest direct human endurance and training-adaptation evidence is for the Veech Ketone Ester.
Don't ask whether ketones were studied. Ask which ketone was studied.
What ketone was used in the well-known 2% endurance study?
The Cox et al. 2016 study used the Veech Ketone Ester — the D-BHB ketone monoester — alongside carbohydrate.
It did not test R 1,3 butanediol, ketone salts or an acetoacetate diester. Athletes completed an hour of steady work before a 30-minute time trial and travelled about 2% farther in the ketone-ester condition.
Worth knowing, because that study is widely cited when discussing products that don't contain the molecule it tested.
Do ketones replace carbohydrates during endurance exercise?
Not necessarily.
Some of the strongest acute VKE performance results were produced alongside carbohydrate, not instead of it. Cox 2016 used both. The 3-hour race protocol had riders taking 60g of carbohydrate per hour throughout.
VKE provides another oxidizable fuel substrate. That doesn't mean carbohydrate becomes unnecessary for every athlete or every event.
Carb-free racing is a separate use case, and a real one — particularly for athletes deliberately training or racing with low carbohydrate availability.
Which KetoneAid format should I choose?
All three are the same Veech Ketone Ester at different dilutions, so the choice is about concentration, taste and how you want to dose.
Ke4 is 50% and carries 30g per bottle — the most ester in the fewest bottles, and the most potent taste. Ke2 is 25% with 25g per bottle: three times the water of Ke4 at the same cost per gram, and easier to get down. The Ketone Shot is 8% with 5g per bottle, ready to drink with nothing to measure.
For daily use through a training block, most athletes end up on Ke4 or Ke2 on cost per gram.
FULL REFERENCES AND STUDY DETAILS
COX 2016Cox PJ, Kirk T, Ashmore T, et al. Nutritional ketosis alters fuel preference and thereby endurance performance in athletes. Cell Metabolism, 2016;24(2):256–268. PMID 27475046. PubMed
POFFÉ 2021 · BICARBONATEPoffé C, Ramaekers M, Bogaerts S, Hespel P. Bicarbonate unlocks the ergogenic action of ketone monoester intake in endurance exercise. Medicine & Science in Sports & Exercise, 2021;53(2):431–441. PMID 32735112. PubMed
POFFÉ 2021 · CAUTIONARYPoffé C, Wyns F, Ramaekers M, Hespel P. Exogenous ketosis impairs 30-min time-trial performance independent of bicarbonate supplementation. Medicine & Science in Sports & Exercise, 2021;53(5):1068–1078. PMID 33196605. PubMed
WORLDTOUR 2024Effects of ketone monoester and bicarbonate co-ingestion on cycling performance in WorldTour cyclists. International Journal of Sport Nutrition and Exercise Metabolism, 2024;34(1).
ROBBERECHTS 2026Robberechts R, Bekhuis Y, Stalmans M, et al. Post-exercise ketone supplementation improves endurance performance and mitochondrial adaptations during an 8-week endurance training intervention. The Journal of Physiology, 2026. doi 10.1113/JP290315.
POFFÉ 2019Poffé C, Ramaekers M, Van Thienen R, Hespel P. Ketone ester supplementation blunts overreaching symptoms during endurance training overload. The Journal of Physiology, 2019;597(12):3009–3027. PMID 31039280. PubMed
POFFÉ 2023Poffé C, Ramaekers M, Van Thienen R, Hespel P. Exogenous ketosis elevates circulating erythropoietin and stimulates muscular angiogenesis during endurance training overload. The Journal of Physiology, 2023;601(12):2345–2358. PMID 37062892. PubMed
NOT THE MONOESTERLeckey JJ, Ross ML, Quod M, Hawley JA, Burke LM. Ketone diester ingestion impairs time-trial performance in professional cyclists. Frontiers in Physiology, 2017;8:806. PMID 29109686. Acetoacetate diester. PubMed · Shaw et al. 2019, racemic R,S-1,3-butanediol, D-BHB ~0.44–0.79 mM during exercise.
LINTS 2026Lints BS, et al. Ketone monoester ingestion and cognitive and physical performance during exercise-heat stress. Journal of the International Society of Sports Nutrition, 2026. PMID 42460838. Endurance-trained males; VKE plus caffeine versus energy-matched carbohydrate plus caffeine. PubMed
QUINONES 2022Quinones MD, Lemon PWR. Ketone ester supplementation attenuates the decline in cognitive performance during simulated team-sport exercise. PMID 36297060. Choice-reaction accuracy declined 1.3% with VKE versus 3.4% on placebo. PubMed
EVANS 2019 · NULLEvans M, McSwiney FT, Brady AJ, Egan B. No benefit of ingestion of a ketone monoester supplement on 10-km running performance. Medicine & Science in Sports & Exercise, 2019;51(12):2506–2515.
POFFÉ 2020 · NULLPoffé C, Ramaekers M, Bogaerts S, Hespel P. Exogenous ketosis impacts neither performance nor muscle glycogen breakdown in prolonged endurance exercise. Journal of Applied Physiology, 2020;128(6):1643–1653. PMID 32407242. 12 highly trained cyclists; no glycogen sparing. PubMed
POFFÉ 2021 · HYPOXIAPoffé C, Robberechts R, Podlogar T, Kusters M, Debevec T, Hespel P. Exogenous ketosis increases blood and muscle oxygenation but not performance during exercise in hypoxia. American Journal of Physiology — Regulatory, Integrative and Comparative Physiology, 2021;321:R844–R857.
ULTRA-ENDURANCE ALERTNESSPoffé C, et al. Exogenous ketosis increases circulating dopamine concentration and maintains mental alertness in ultra-endurance exercise. Journal of Applied Physiology. PMID 37141424, doi 10.1152/japplphysiol.00791.2022. 18 recreational runners attempting 60–100km. PubMed
CARPENTER 2026 · NOT VKECarpenter M, Brouner J, Spendiff O. Acute 1,3-butanediol co-ingestion with carbohydrate does not improve endurance performance in chronically ketogenic male athletes. Nutrients, 2026;18(14):2388. PMID 42514457, doi 10.3390/nu18142388. A 1,3-butanediol study, not a Veech Ketone Ester study. PubMed
EVANS & EGAN 2018Evans M, Egan B. Intermittent running and cognitive performance after ketone ester ingestion. Medicine & Science in Sports & Exercise, 2018;50(11):2330–2338.
ROBBERECHTS 2022Robberechts R, Poffé C, Hespel P. Exogenous ketosis suppresses diuresis and atrial natriuretic peptide during exercise. Journal of Applied Physiology, 2022;133:449–460.
DEARLOVE 2019 · CAUTIONDearlove DJ, Faull OK, Rolls E, Clarke K, Cox PJ. Nutritional ketoacidosis during incremental exercise in healthy athletes. Frontiers in Physiology, 2019;10:290.
PHARMACOKINETICSStubbs BJ, Cox PJ, Evans RD, et al. On the metabolism of exogenous ketones in humans. Frontiers in Physiology, 2017;8:848. PMID 29163194. Ester peak D-BHB 2.8 mM vs ketone salts 1.0 mM at matched dose. PubMed
EXPLORE ENDURANCE BY SPORT
The evidence is here. The application is yours.
This page covers what the research shows across endurance generally. Sport-specific protocols get their own pages.
