For many of us, drinking too much coffee can lead to a number of problems – ranging from shaky hands, a rapid heart rate, and an underlying sense of anxiety. These side effects are usually the result of consuming high quantities of caffeine.

To avoid these health issues, many people opt for decaf coffee. But in recent years, naturally low-caf varieties like Laurina have also become a popular choice, allowing consumers to enjoy specialty coffee without compromising on quality.

There is, however, a seemingly new decaf alternative on the market: Paraxanthine (or Px) coffee. So what exactly is it and could it have an impact on the coffee industry?

To find out, I spoke with Jeffrey Dietrich, CEO of Rarebird Coffee, and Chahan Yeretzian, Professor of Chemistry and the Head of the Coffee Excellence Center at the Zurich University of Applied Sciences.

You may also like our article on why drinking too much coffee can cause caffeine “jitters”.

What is Px?

In the simplest terms, Px is the main product of the metabolism of caffeine. 

Coffee plants synthesise caffeine from the organic molecule xanthosine. When we consume caffeine, the human body metabolises it primarily using the enzyme cytochrome P450, which breaks down about 80% of the caffeine content into Px, with the remaining 20% broken down into theobromine and theophylline.

Because coffee plants don’t synthesise Px when producing caffeine, outside of the human body, scientists have to create Px in a lab. This is done by breaking down caffeine through an enzymatic process similar to the one in your liver. 

Caffeine and Px essentially work the same way in the body. A 1995 clinical trial showed that both caffeine and Px inhibit adenosine receptors – resulting in mental stimulation, the release of adrenaline and dopamine, and kickstarting the sympathetic nervous system (the fight or flight response). Px has also been found to produce similar cardiovascular, hormonal, and metabolic effects to caffeine. 

Px as a food and beverage ingredient, however, is not a new concept, with many commercially-available energy drinks and workout supplements containing this ingredient. But Px coffee is quite unique.

As of now, Rarebird is the first and only company to sell Px coffee – and even won the Best New Product Open Class category award at the 2023 Specialty Coffee Expo in Portland, Oregon.

Jeffrey explains that Px coffee is essentially identical to “traditional coffee” – it can be brewed the same way, and also smells and tastes the same. He says Rarebird starts by roasting high-quality decaffeinated beans before infusing them with Px provided by its supplier.

Does Px impact coffee flavour and mouthfeel? 

Chahan explains that Px has very little effect on coffee sensory profiles.

“Given the quantities [of Px] used, the impact on flavour is negligible,” he says. He adds that isolated caffeine only has a slight taste, and that Px has even less.  

Jeffrey agrees, saying: “I can confidently say Px is very comparable to caffeine in terms of taste. You’re not going to see any difference in terms of mouthfeel and the organoleptic properties of coffee.”

He adds that Rarebird has been working with Major Cohen, a retired Senior Project Manager at Starbucks, and Paul Songer, a head judge at Cup of Excellence, to source high-quality decaf options. The company currently only offers medium roast Colombian coffee, but will start selling different origins and roast profiles in the coming months.

What are the benefits of drinking Px coffee?

Although Px coffee is a relatively new concept, there are over a decade of in vitro and clinical trials that demonstrate the various health benefits of Px. These include:

• A 2012 study on rats which showed that Px is a stronger stimulant than caffeine
• A 2015 study on rats which showed that caffeine and Px increased brain dopamine levels, and that Px did so more effectively
• Another 2015 study on rats which suggested that Px enhances athletic performance to a greater extent than caffeine – and more consistently between individuals who are both slow and fast caffeine metabolisers
• A 2021 clinical trial of enfinity Px showed that daily consumption of Px improved measures of cognition, memory, reasoning, response time, and attention
• In 2023, Rarebird funded a study of Px which suggests it is a safer alternative to caffeine for achieving similar stimulant effects

Moreover, research also indicates that genetics play a huge role in how the body metabolises caffeine, and therefore the extent of its effects. Individuals who produce less of the enzyme cytochrome P450 metabolise caffeine more slowly. This means they are more likely to feel its negative effects when consuming higher quantities. 

“I wouldn’t go further than saying Px’s difference from caffeine in this regard is a hypothesis developed from Px coffee drinker feedback and anecdotes,” he adds. “We’re excited to see what future clinical studies show, but I’d want to see those results before claiming these benefits.”

He notes that Px won’t have as much of an effect on people who are tolerant of caffeine.

“But for a lot of people – probably the majority of whom do experience that jittery, over-caffeinated feeling – you’ll feel a difference with Px coffee.”

Does Px have negative health effects?

Many clinical studies have indicated that Px consumption has little to no negative side effects, but it’s important to note that Px-infused coffee and other products are not made naturally.

“Most people don’t know anything about Px, but it’s not because we don’t feel it or aren’t exposed to it – we actually know it way better than we think we do,” Jeffrey says. “We’re not making something new, strange, or scary that your body hasn’t already experienced.”

He adds that while much more research needs to be carried out on Px coffee specifically, he believes there are more benefits to discover.

Chahan also points out that people who metabolise caffeine more quickly will probably have to drink more Px coffee to feel similar effects.

“I would assume that for the same level of effect in terms of physical and mental improvement, you will probably need to intake a higher dose compared to caffeinated coffee,” he says.

Similarly, for fast caffeine metabolisers, Px coffee doesn’t offer the same adrenaline rush that caffeine can – which can be both a pro and a con.

“The big difference I see between caffeine and Px is that caffeine triggers the body’s fight and flight response,” Jeffrey explains. “Px doesn’t trigger that.”

Could consumption of Px coffee grow in the coming years?

Given the recent boom in popularity of the functional coffee market, there is certainly potential for Px coffee to become more available – although decaf is likely to always remain the most popular caffeine-free option.

Jeffrey says Rarebird launched a subscription service in August 2023 which has received favourable feedback from consumers, including improved sleep quality and the ability to drink coffee later in the day.

“Around 92% of our customers are telling us they feel better when drinking Px coffee compared to caffeinated beans,” he adds.

Chahan also believes the wider market of fortifying coffee with functional ingredients will grow in the coming years as consumers become more focused on quality and health.

Alongside decaf, half-caf and low-caf options are steadily becoming more popular among consumers who want to be more mindful of their caffeine intake.

And as we learn more about Px coffee, it could certainly have an impact on the industry – and more roasters and companies could start selling their own products. For now, let’s wait and see.

Enjoyed this? Then read our article on whether low-caf varieties could replace decaf.

Photo credits: Rarebird Coffee

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