One of the world's first commercial ketone esters, a drink that could improve energy and athletic performance, is coming to market.

HVMN is a startup based in San Francisco that wants to usher in a new era of human enhancement through technologies like the ketone ester.

We tried the drink before its public launch.

About 13 years ago, the Defense Advanced Research Projects Agency (DARPA) asked the scientific community to create a food that soldiers could take onto the battlefield. The agency, which has been tasked with building breakthrough technologies for the US military, wanted to improve troops' physical and mental performance, turning war fighters into super-soldiers.

Researchers at University of Oxford and National Institutes of Health answered the call. With $10 million in funding from DARPA, a team of biochemists invented the ketone ester, a drink that generates energy from ketones — molecules formed by the breakdown of fat — rather than carbs, fat, or protein. It is, effectively, a fourth type of fuel for humans.

On November 6, HVMN, a startup out of San Francisco, revealed that it is bringing one of the first commercial ketone esters to market. HVMN Ketone is an FDA-reviewed drink that promises increased athletic ability, heightened focus, and energy. The company is leveraging more than a decade and $60 million-worth of research from Oxford through an exclusive partnership.

The HVMN Ketone product packaging. HVMN

Starting today, anyone will be able to buy the product for $99 online. It ships in December.

HVMN, an Andreessen Horowitz-backed startup whose other products include chewable coffee and "smart drugs," will market the product to competitive athletes to start. (Most clinical trials on the drink studied its effects on elite athletes.) But the company expects "biohackers" — people interested in enhancing their body's performance — to be interested in ketone esters as well.

Ketones offer a plan B fuel source

The nutrition label on a bottle of HVMN Ketone defies traditional explanation. A 2.2-oz shot of the drink contains 120 calories — roughly the equivalent of a hearty slice of bread — yet it has no fat, no protein, and no carbohydrates.

Those calories instead come from ketones, an ingredient that Geoff Woo, cofounder and CEO of HVMN, likes to call "the fourth macronutrient."

"It's not a fat, it's not a protein, it's not a carb, but your body gets fuel from it," Woo told Business Insider.

Unlike the other three macronutrients, the human body naturally makes ketones in the absence of food. When we're starving, our bodies dig into their fat stores to survive, releasing molecules called ketones in the process. A high-fat, low-carb diet (also known as a "ketogenic diet") is a shortcut to the same goal. Instead of going without food, someone on the diet tricks the body into believing it is starving by snatching away carbohydrates, its primary source of fuel.

Ingesting those ketones directly appears to super-charge the body, according to Kieran Clarke, a professor of physiological biochemistry at the University of Oxford and the scientist leading the charge to translate her work on ketones and human performance into HVMN Ketone.

Clarke's work in athletes suggests that drinking ketones alongside a carb-rich meal like a piece of pizza or a granola parfait provides a performance boost that's "unlike anything we've ever seen before," she told Business Insider.

This is an energy drink that supercharges the human body

In a small study published in July 2016 in the journal Cell Metabolism, Clarke gave an early version of HVMN's ketone drink to a group of elite cyclists (some of whom were former Olympians) and compared how they performed on a 30-minute cycling exercise to two other groups who were either given a carb-rich drink or a fat-rich drink.

The high-performing cyclists on the ketone drink went an average of 400 meters further than the best performers who'd had the carb or fat drink. They likely didn't even feel a difference, Clarke said.

"It's not like caffeine or anything, it's not a stimulant. If you're not watching what you're doing, you think, 'Oh I'm doing alright, everything feels normal,' but then you look down and all of a sudden you see, 'Oh, wow, I've gone a lot further than usual!' You’ll find on a rowing machine, for example, you're going a lot faster and you didn't even realize it," Clarke said.

A bottle of HVMN Ketone delivers 25 grams of beta-hydroxybutyrate (BHB), one of the substances the body naturally produces during a fast or a period of starvation.

Within an hour of consuming it, the drink can raise ketone levels to a level similar to what you would see after at least seven days of fasting. That's based on two small studies published in the journal Frontiers in Physiology in which adults were given drinks containing either ketone ester or ketone salts, a supplement that combines ketones and sodium.

It's worth noting that most of the research supporting ketones in humans is exclusively in athletic performance — not cognition — so the benefits we noticed when trying HVMN's Ketone should be taken with a grain of salt. The placebo effect is a small but very real phenomenon.

We felt great after trying it, with some caveats

We (Melia Robinson, an innovation reporter, and Erin Brodwin, a science correspondent) had a chance to try HVMN Ketone in October.

The drink comes in a bottle about the size of a 5-Hour Energy shot. It's clear and has no smell. The taste, however, burns like rubbing alcohol. It caused our eyes to tear. We gagged, loudly.

Clarke doesn't deny that the taste is the drink's worst quality. "At least it doesn't smell. It just tastes ghastly! But then it goes!" she said.

Still, after a few minutes, our stomachs ached. A flavor like nail polish remover lingered on our lips long after drinking and was only extinguished with ice water.

Reporters Melia Robinson and Erin Brodwin clink bottles of HVMN Ketone before trying it. Geoffrey Woo

Erin noticed a curb in her appetite, while Melia felt jittery. Brianna Stubbs, lead researcher at HVMN and a postgraduate student at the University of Oxford who worked under Clarke, described the sensation as "you could run up a wall, but you don't want to."

We noticed it was easier to focus on work. We cranked away on writing, skipped our usual afternoon cups of coffee, and avoided snack binges over the next several hours. Both times we tried the drink, we noticed that its effects wore off after between four and six hours — faster during times of frequent physical activity and slower when we were sedentary.

Two people do not make for a sufficient sample size in a study of the drink's effects, but our personal experiences were positive overall.

While it's hard to separate our perception from any placebo effect, HVMN Ketone produced measurable physical results for us. Stubbs performed two tests — a blood-glucose test and a ketone test — three times during the course of our trial. Using a small digital meter, she pricked our fingers the first time before we drank the ester, again 30 minutes later, and one hour after drinking.

During the hour before and the hour after we drank the ester, Melia's ketone levels rose from 0.6 mmol/l, a low-level state of ketosis, to 6.0 mmol/l, a deep state of ketosis that can typically only be achieved through fasting. Erin's ketone levels rose from 1.2 mmol/l to 4.2 mmol/l. Most people maintain a non-existent level of ketosis of 0.1 mmol/l, but we started with higher levels because one of us happened to be eating a low-carb diet while the other was trying a fast.

Michael Brandt and Geoffrey Woo are the cofounders of HVMN. HVMN

It's not hard to imagine Silicon Valley tech workers buying a ketone ester from their local drug store, instead of a $9 coffee drink, to fuel them during marathon coding sessions. However, the $99 price tag for three bottles (or $396 for a 12-pack) will be prohibitive for most.

In 2016, HVMN reported $1 million in sales over the previous year, with 17% growth month-over-month. Woo and his cofounder, Michael Brandt, appeared on "Shark Tank" to pitch their chewable coffee product, Go Cubes. They tried to raise money from the sharks with a $40 million valuation, which is more than any startup has ever asked for on the show, and left empty-handed.

Woo said the company will continue to invest heavily in research and development, as well as clinical trials. HVMN wants to pave a path for biohacking products that's grounded in science.