Scientists are testing a keto cocktail for longevity and vigor — without the high-fat diet

• Ketones are an energy source the brain can use in place of sugar.
• Scientists are testing whether ketone ester drinks may improve human longevity.
• But drinking ketones doesn't do the same things for your body as a ketogenic diet.

It's not a fountain of youth, but it may be a tiny sip of it.

Scientists at the Buck Institute for Research on Aging in northern California are preparing to study whether a twice-a-day tropical-flavored shot could boost human longevity. The idea is that older people who drink ketone esters — supplements designed to help the body run on ketones instead of sugar — might be able to gain some renewed pep in their step.

Ketones already have a lot of street cred with Silicon Valley biohackers, who celebrate them as the body's "preferred" energy source because they're what our bodies use for fuel when we're fasting or when we don't have enough glucose circulating to keep all of our organs humming along.

"Actually, they're the preferred backup," Brianna Stubbs, the director of translational science at the Buck Institute, told Business Insider.

Ketones are what our body generally burns when it doesn't have enough carbs at the ready. "Whenever there are ketones in the blood, the body will use that as energy in preference to sugar," she said.

When ketones are coursing through a person's bloodstream, they're said to be "in ketosis" because ketones — and not glucose — are providing the fuel for their cells.

Ketosis is a tool that evolved to protect our brains and bodies from damage during periods of famine. Scientists think this natural ketone metabolism safety switch we've developed could also be harnessed for healthy aging, because a number of organs, including the brain, become less efficient at using sugar for fuel as we age.

The nationwide study that Stubbs and her mentor, Dr. John Newman, are launching will aim to measure whether older people drinking ketone shots become less frail, with better walking scores, or experience improvements in energy, cognition, or mood.

Ketone drinks are not ketogenic diets in a bottle

Fasting, low-carb, high-fat diets like keto, and drinking ketone esters can all prompt ketones to circulate in a person's blood. But they don't get to that end result in the same way.

Ketone ester drinks don't require the liver to convert fat into ketones, which is what happens with fasting and the keto diet. Instead, they deliver ketones straight to the stomach and the liver, where they are processed and pushed out into the bloodstream.

"If you were wanting to lose weight, you want to be burning your own fat and turning it into ketones," Stubbs said. Ketone drinks don't do that. "You have not burned your own fat to make those ketones. It's not a shortcut."

For several years, scientists thought ketone drinks might be good for athletic performance, taken as a pre-race drink. Even the US military invested in the idea. But more recently, Stubbs and other athletes have coalesced around the idea that ketone esters are better tools for athletic recovery.

That's how the former Olympic rower uses them. Stubbs recently completed a six-day, 380-kilometer ultramarathon through the craggy mountains of Wales. During her rest stops, she drank ketone esters alongside carbs and protein. She hopes this strategy helps her body recover after hard workouts, maintaining muscle and vigor.

Because older people already have more trouble using sugar, there's also some hope that ketone esters might be good for helping their bodies maintain strength, potentially reducing inflammation, boosting mood, and improving cognitive function. But that all remains to be seen.

Independent fasting and ketosis expert Mark Mattson, former head of the National Institute on Aging's neuroscience lab, said the study is "worth trying."

"There is some rationale for why it might help, and it's very safe," he told Business Insider.

Mattson's excited to see what kind of effect these drinkable ketones might have on aging brains in particular, since they are more susceptible to cognitive impairment and diseases like Parkinson's.

But he also says getting into ketosis through other techniques like intermittent fasting has extra benefits for the body and the brain that shouldn't be discounted.

In an initial pilot study Stubbs recently completed at the Buck, ketone drinks appeared safe for adults over 65 when tested during a four-month period. The most common complaints were nausea and upset stomachs, which are common issues with ketosis, even when achieved through fasting or low-carb diets.

The new, bigger trial will be a five-month study of 180 adults over 65 years old in California, Connecticut, and Ohio, testing whether ketone esters might help with frailty. Recruitment starts in November.

In order to test whether a ketone drink might actually be helpful for aging, Stubbs is aiming to recruit "people who would probably self-describe as slowing down," she said. Maybe these days, walking two blocks is more of a challenge for them than it used to be.

Results from the study won't likely be available until 2028, Stubbs said. Assuming positive outcomes eventually surface, she imagines a future in which an older adult who's losing muscle and starting to experience cognitive decline might have a ketone drink every morning and night. But she also says that any eventual geriatric recommendation for ketone esters isn't likely to be one-size-fits-all.

"If I had my super fit, healthy 90-year-old who took one statin and that was it, and she had no other problems and everything was functioning fine for her, I'd be like, 'Well, you're just adding something else in there that maybe you don't need,'" Stubbs said.