Ketones at Altitude: What 5 Studies Show Before Ski Season

Ski season is open in Colorado, and friends driving up I-70 keep asking me whether ketones help at altitude. Your brain and muscles run short on oxygen up there, and animal research suggests BHB yields a bit more energy per unit of oxygen than glucose does. I went through the human research on ketones at altitude, including a real-mountain trial published in September.

The results are more mixed than the marketing online. The promising studies used high-dose ketone esters in altitude chambers, and the one four-day study on an actual mountain found no difference in altitude sickness. Here is what each tested, why esters and salts may differ up high, and how I’d use goBHB® on a ski trip.

What Altitude Does to Your Body

At 9,000 to 12,000 feet, where many Colorado ski areas sit, each breath carries less oxygen. Blood oxygen saturation drops, your breathing rate rises, and some people get headaches, poor sleep and nausea in the first day or two. That cluster is called acute mountain sickness, and it is a medical condition that deserves real attention. The standard advice still applies: go up gradually, hydrate, limit alcohol the first night and head down if symptoms worsen.

Rodent studies linked higher blood ketones with better tolerance of low oxygen, so European exercise physiologists and a US team working with military personnel tested ketone drinks in people.

The Chamber Studies on Ketones at Altitude

Cyclists in thin air (Poffé 2021)

Fourteen highly trained male cyclists rode a 3-hour simulated race while oxygen was lowered step by step, from 18.6% to 14.5%. They took 75 g of a ketone ester or a control drink, plus 60 g of carbohydrate per hour, in a crossover design. The ester offset about 3% of the drop in blood and muscle oxygenation. Time-trial and sprint performance did not change.

Military personnel at a simulated 20,000 feet (McClure 2024)

Sixteen male military personnel sat at rest while breathing air equal to 6,096 m (about 20,000 feet). They took a ketone monoester at 650 mg per kg of body weight, split in two doses, or placebo, in a single-blind crossover. Blood BHB rose above 4 mM within 30 minutes, and blood glucose ran about 20 mg/dL lower than placebo. Oxygen saturation averaged 76.8% with the ester and 70.4% with placebo, and participants got 6.8 more correct answers per minute on a code substitution task. The authors disclose that HVMN Inc. had no involvement in data collection, analysis or interpretation.

A companion study from the same team had 16 men carry a 22 kg ruck on an incline at a simulated 4,572 m. The ester (573 mg/kg, taken with 40 g of dextrose) limited the drop in oxygen saturation by 2.4% to 4.2%, but cognitive scores did not differ from placebo.

Blood oxygen at a simulated 6,096 mAverage oxygen saturation (SpO2) during 20 minutes at rest, ketone monoester vs. placebo (McClure 2024).Placebo70.4%Ketone monoester (650 mg/kg)76.8%Source: McClure TS, et al. Exp Physiol. 2024;109(10):1672-1682.

A 29-hour altitude chamber stay (Stalmans 2024)

The same European group then kept 14 healthy men at a simulated 4,000 to 4,500 m for up to 29 hours, once with a ketone ester and once with placebo, and stopped the test if someone developed severe altitude sickness. Blood BHB held around 3 mM with the ester. On average, participants lasted 32% longer with the ester, and the nine who developed severe symptoms lasted about twice as long. The ester also caused mild metabolic acidosis and faster breathing.

The Real-Mountain Trial That Found No Difference

In September 2026, Tominec, Stalmans and colleagues published the study I think matters most for skiers. Thirty-four people spent four days at 3,375 m on a real mountain, about 11,000 feet, taking either regular ketone ester doses or placebo. Blood BHB rose after the doses.

Altitude sickness incidence peaked at 25% to 35% around 8 hours, and it was similar in both groups (P ≥ 0.822). The ester made people breathe harder and raised daytime cardiac output, but it did not improve blood or brain oxygenation compared with placebo. The authors concluded the ester does not seem to meaningfully change altitude sickness during early acclimatization, and they declared no conflicts.

Why BHB Salts May Not Do the Same Thing

One plausible explanation is acid load: in Stalmans 2024 the ester caused mild metabolic acidosis and faster breathing, which would raise blood oxygen. The ester did the same on the real mountain without better oxygenation, so that isn’t the whole story. In the 2017 study on how people absorb ketone drinks, Stubbs and colleagues found the ketone ester lowered blood pH by 0.10, while the sodium and potassium BHB salt drink raised urine pH from 5.7 to 8.5. The salt drink did not produce that acid load.

Dose is the other gap. At matched doses (the study tested roughly 12 and 24 g of BHB), peak blood D-BHB was 2.8 mM with the ester versus 1.0 mM with the salt drink. Half the salt drink’s BHB was L-BHB, which that figure excludes. Poffé used 75 g of ester, and McClure’s 650 mg/kg works out to about 56 g for the average participant. A can of MAC Energy has 2 g of goBHB. I haven’t found a published study of BHB salts at altitude, and I won’t pretend the ester data transfers. For more on the two forms, read Ketone Salts vs Ketone Esters.

Ketone dose: altitude studies vs. a product servingGrams of ketone ester (studies) or goBHB (MAC Energy) per session or serving.Poffé 2021 (ketone ester)75 gMcClure 2024, 86 kg adult (ketone ester)56 gMAC Energy (1 can, goBHB)2 gSources: Poffé 2021; McClure 2024 (650 mg/kg at the study’s average body mass of 86.2 kg); drinkmac.com label.

How I Use goBHB on a Ski Trip

I use goBHB at altitude the same way I use it at home, as fuel for focus and energy, not altitude medicine. These are the two products I pack.

CleanForm goBHB Energy Shot: L-goBHB, zero caffeine, zero sugar, 2 oz.

The CleanForm goBHB Energy Shot fits in a jacket pocket. Sleep often suffers at altitude, so I like that it has no caffeine. It has zero sugar and is TruShield Certified. I compared it with MAC Energy in Caffeine-Free Energy Shot or MAC Energy?

MAC Energy: 2,000 mg goBHB, 200 mg Purcaf® caffeine and 250 mg Cognizin® per 12 oz can.

MAC Energy is my morning can before first chair, and I keep its 200 mg of caffeine to the morning. The ester lowered blood glucose about 20 mg/dL in the McClure resting study, and a 2022 meta-analysis of 43 trials found an average drop of about 0.5 mM after exogenous ketones, larger with monoesters than salts. On a long ski day, eat real carbs. For timing, see How Long Do Ketones Last?

Safety notes: if you have heart, lung or kidney problems, high blood pressure, or take prescription medication, talk with your doctor before a high-altitude trip and before using ketone supplements. Skip caffeine if you are sensitive to it or pregnant. If altitude symptoms get worse, go down and get medical help.

Where the Evidence Stands

In chambers, high-dose ketone esters raised blood oxygen saturation a few points, and one chamber study found people tolerated a 29-hour stay longer. The only real-altitude trial so far, four days at 3,375 m, found no difference in altitude sickness or oxygenation. Exercise performance did not improve in Poffé 2021, cognitive results were mixed across the two McClure studies, and every study tested esters, with the chamber studies enrolling only men.

I haven’t found a published study of BHB salts or goBHB at altitude. None of these products are meant to treat or prevent any disease.

FAQ

Do ketones help with altitude sickness?

A 2024 chamber study found a high-dose ketone ester let people tolerate simulated altitude longer, but a 2026 trial on a real mountain found no difference in altitude sickness over four days. I haven’t found a study on BHB salts, and goBHB is not intended to treat or prevent altitude sickness. The proven approach is a gradual ascent, then rest or descent.

Do ketones raise blood oxygen at altitude?

In chamber studies, ketone esters raised oxygen saturation by roughly 2% to 6% compared with placebo. In the real-altitude trial, the ester did not improve blood or brain oxygenation.

Should I take BHB before skiing?

If you already use goBHB for energy and focus, there’s no reason to stop on a ski trip. Just don’t expect it to work like altitude medicine, and eat carbs and stay hydrated. In the afternoon, a caffeine-free shot is easier on sleep.

The Bottom Line

The altitude research is good science with a modest result: esters nudged blood oxygen up in a chamber, and the first real-mountain trial found no difference in altitude sickness. BHB salts have not been tested. Use goBHB on the mountain for the same reasons you use it at home, and follow standard altitude advice for the rest.

Sources: Tominec D, Stalmans M, et al. Intermittent exogenous ketosis does not reduce acute mountain sickness during early terrestrial high-altitude acclimatization. Eur J Appl Physiol. Published online Sept 8, 2026. Stalmans M, et al. Exogenous ketosis attenuates acute mountain sickness and mitigates normobaric high-altitude hypoxemia. J Appl Physiol. 2024;137(5):1301-1312. McClure TS, et al. Ketone monoester attenuates declines in cognitive performance and oxygen saturation during acute severe hypoxic exposure under resting conditions. Exp Physiol. 2024;109(10):1672-1682. McClure TS, et al. Ketone monoester attenuates oxygen desaturation during weighted ruck exercise under acute hypoxic exposure. Exp Physiol. 2024;109(10):1768-1781. Poffé C, et al. Exogenous ketosis increases blood and muscle oxygenation but not performance during exercise in hypoxia. Am J Physiol Regul Integr Comp Physiol. 2021;321(6):R844-R857. Stubbs BJ, et al. On the Metabolism of Exogenous Ketones in Humans. Front Physiol. 2017;8:848. Falkenhain K, et al. Effects of Exogenous Ketone Supplementation on Blood Glucose: A Systematic Review and Meta-analysis. Adv Nutr. 2022;13(5):1697-1714. Product details from drinkmac.com and cleanformnutrition.com.