About Paraxanthine | The Science & Benefits of Px

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Px is... Caffeine 2.0

Everything you want from caffeine, without the side-effects.

What is Px

Paraxanthine (also called Px) is a natural metabolite of caffeine. All that means is that Px is made in the body when the liver metabolizes, or breaks down, caffeine. In fact, the majority of caffeine in our bodies is converted to Px.

It can also be found in very small amounts in some foods, including coffee beans, Theobroma cacao fruits, citrus flowers, and Sicilian orange flower honey.

Like caffeine, Px increases alertness, reduces fatigue, and decreases drowsiness. However, Px is less likely than caffeine to cause negative side effects, including “jitters”, anxiety, irritability, and nervousness.

High Performance Bean-efits

Recent studies (both by Rarebird and by independent researchers) on paraxanthine have shown many potential benefits of Px:

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Better Sleep

Px can improve your sleep quality. In mice, Px showed no evidence of sleep rebound (debt) compared to caffeine, while providing the same amount of wakefulness at equimolar concentrations.

Energy & Endurance

In some studies, Px has been shown to boost nitric oxide production, leading to increased treadmill endurance, grip strength, and muscle mass.

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Reduced Stress

In animal and clinical studies, caffeine is anxiogenic (anxiety increasing). In contrast, Px has been shown to exhibit anxiolytic (anxiety decreasing) properties.

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Elite Focus

Px has been shown to have cognitive performance benefits and may even help to preserve dopaminergic neurons, helping to protect against age-related cognitive decline.

Better Sleep

Px can improve your sleep quality. In mice, Px showed no evidence of sleep rebound (debt) compared to caffeine, while providing the same amount of wakefulness at equimolar concentrations.

Energy & Endurance

In some studies, Px has been shown to boost nitric oxide production, leading to increased treadmill endurance, grip strength, and muscle mass.

Reduced Stress

In animal and clinical studies, caffeine is anxiogenic (anxiety increasing). In contrast, Px has been shown to exhibit anxiolytic (anxiety decreasing) properties.

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Px vs. Caffeine

The energy-boosting effects of caffeine come from it's ability to inhibit Adenosine receptors A1 and A2A.

We measured Px and caffeine head-to-head, and the results speak for themselves: Px is up to 2.7x (A1) and 3.5x (A2A) more effective than caffeine.

This means Px has the ability to provide all the focus, energy, and performance of caffeine—but without the jitters, anxiety, and impact on sleep quality.

Is Px Safe?

Paraxanthine has GRAS (Generally Regarded As Safe) status and as compared to caffeine, has a higher oral LD50 (829-1601 mg/kg vs. 127-367 mg/kg for caffeine; rodent) and NOAEL (no adverse effect level)—185-300 mg/kg vs. 150 mg/kg.

Additionally, Px has been shown to have a shorter half-life (3.1 hours) than caffeine (4.1h) and the other major caffeine metabolites, theobromine (7.2h) and theophylline (6.2h), meaning it is processed and cleared from the body faster, so it is less likely to negatively affect sleep quality.

Both paraxanthine and caffeine are CNS stimulants. As such, Px is not intended for use by children and you should consult your physician if you are pregnant, lactating, have a medical condition, or are taking any medications.

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Who have experienced the difference

"I was a true coffee lover since my teens, but after my 2nd pregnancy things changed & I couldn't handle it anymore. I wasn't able to have coffee anymore because of major jitters & blood sugar crashes, and too frequent bathroom breaks. Sadly I gave it up. Decaf was ok, but it was never as good and I could handle tea caffeine, so I stuck with that. But I can drink Rarebird! It truly doesn't cause any of these problems for me and it really is a miracle. I can finally enjoy coffee, even in the (early) afternoon."

M.S.

Verified Buyer

"Absolute life changer for me, given my sensitivity to caffeine. I’d switched completely to decaf since I’m no longer able to tolerate caffeine, but discovering Rarebird has been a godsend... Dark roast is some of the best coffee I’ve ever had."

Brendan

Verified Buyer

"I’m pretty sensitive to caffeine (and find the extended half life can interrupt my sleep, even when my last cup is around 1pm), but I’ve noticed a big difference with the Px in Rarebird... Rarebird is now basically the only coffee I drink"

Jeremy

Verified Buyer

M.S.

Verified Buyer

Brendan

Verified Buyer

Jeremy

Verified Buyer

"I almost never write reviews, but this coffee is nothing short of a revelation. It delivers all the amazing perks of caffeine—focus, energy, and clarity—without any of the usual downsides. No crashing. No grogginess the next day. Just pure, clean energy that keeps you in the zone. The paraxanthine infusion has completely transformed my coffee experience, and honestly, my life. It’s become my secret weapon for tackling busy days, and I can’t stop raving about it to everyone I know. This isn’t just coffee—it’s a revolution. I truly believe it’s going to reshape the industry in a way that’s healthier and smarter for all of us."

Ju K.

Verified Buyer

"I’m a slow caffeine metabolizer so I was super happy to find this Px Coffee. I feel focused with no jitters, kinda like I took an adderall. And I have been able to sleep great. If it were regular caffeine id be up all night if I had any past 10am. The flavor is great and works well in my espresso machine."

Michelle R.

Verified Buyer

"I've always been quite sensitive to caffeine, but I also really enjoy drinking coffee. The consequences for [it] were spikes in anxiety and blood pressure. Even still, it seemed like my sensitivity kept getting worse over time, and I eventually... I needed to go caffeine free permanently. It was only a couple months after I made this decision that I found Rarebird... I became a subscriber shortly after trying it. This is the coffee that let me drink coffee again, and I'm really thankful for that. It's great-tasting, high quality coffee too."

Jamin

Verified Buyer

"Love it! 😍 All the benefits of regularly caffeinated coffee without the jitters!"

Paula D.

Verified Buyer

Ju K.

Verified Buyer

Michelle R.

Verified Buyer

Jamin

Verified Buyer

"I used to struggle with sleep and completely eliminated coffee from my diet for more than a year, which was tough but necessary. I wish I'd had Rarebird at that time."

Andrew W.

Wired Magazine

"My sensitivity to caffeine is that I notice a 2nd cup in the afternoon throws off my sleep... I've really enjoyed their Px Coffee. I've only experimented twice... but happy to say no disruption to sleep"

Kevin V.

Verified Buyer

"Tastes amazing and makes me feel more calm... nice to be able to drink later in the day without having to worry about it hurting my sleep."

Kyle B.

Verified Buyer

"Tastes good. Not as tired in the afternoon and easy to fall asleep."

Giovanna A.

Verified Buyer

"I used to struggle with sleep and completely eliminated coffee from my diet for more than a year, which was tough but necessary. I wish I'd had Rarebird at that time."

Andrew W.

Wired Magazine

Kevin V.

Verified Buyer

"Tastes amazing and makes me feel more calm... nice to be able to drink later in the day without having to worry about it hurting my sleep."

Kyle B.

Verified Buyer

"So I’m a coffee drinker. Not more than a cup a day early in the mornings because I have high blood pressure. Other brands I’ve tried increase my blood pressure because of the caffeine content. But since I’ve been drinking this brand of coffee, my pressure went down. 112/76. I’m still taking my blood pressure medicine though. Prior to Rarebird it was 140/85. No jittery, and I sleep like a baby at night time. Thank you to the creator of this coffee. 🙏🙏"

Bola A.

Verified Buyer

"I work in the financial services industry and have depended on coffee / caffeine since 2015 to keep me at 100%. I've tried natural sources of caffeine, tea, energy drinks that promise to be healthy, just water, and even though Coffee has it's draw backs, I've always come back for over a decade. Not anymore. My office just started offering this in the break room. I typically plan my day around caffeine because to avoid experiencing negative side effects (stomach pain, headache, crash), but I wanted to stress test Rarebird and drank 6 cups (2x my daily intake) and all I felt was energy... 10/10 would recommend."

Jeremy J.

Verified Buyer

"Every women over 40 needs to switch to drinking rarebird. Tastes amazing no hormone issues and sleep issues are gone. No more mid afternoon anxiety."

Briana L.

Verified Buyer

"Love this coffee! Smooth, rounded flavor without the hard impact to my stomach and NO JITTERS. Super happy that I discovered Rarebird."

Diana L.

Verified Buyer

Bola A.

Verified Buyer

Jeremy J.

Verified Buyer

"Every women over 40 needs to switch to drinking rarebird. Tastes amazing no hormone issues and sleep issues are gone. No more mid afternoon anxiety."

Briana L.

Verified Buyer

"My wife is like a total snob about coffee and where it’s sourced and... I bought this for her because intimate love and she ended up liking it a lot. Like a-lot-a-lot. Also she says she doesn’t get jitters or caffeine headaches like her usual stuff and she’s about 88% sure she’s not imagining it. But seriously, she can be really pretentious about it (bean quality) and she says it’s actually great."

Stephen K.

Verified Buyer

"It's really wonderful coffee! I have been enjoying it quite a lot. The flavor is incredibly good, and it does give a nice bump of energy without being overwhelming like regular coffee."

Aaron S.

Verified Buyer

"It's really good coffee. These guys have created a fantastic product. If you really love coffee but can't take the caffeine definitely give this a shot. As a caffeine sensitive person, this coffee even at full strength does not give the jitters or a very racy mind. I feel that it also interferes less with sleep, although it probably does have some effect. The taste is bold but balanced, it's really great stuff overall!"

Brian V.

Verified Buyer

Our Mission

At Rarebird, we're bringing metabolic science to everyday real-world issues. We developed Px Coffee to give coffee drinkers all of the focus, energy and performance boost without the stress, anxiety and jitters.

Experience Px Coffee

Patented | Award-winning | Mold-free

The Only Px Coffee

Rarebird is the only Px Coffee on the planet—patented, exclusive, and designed to work with your body, not against it.

Smooth energy. No hijacked stress system. No caffeine crash. Just a better coffee experience.

US Patents 11,872,232 and 12,178,820

Benefits of Px Coffee

Spike-Free Energy

Unlike caffeine, Px Coffee won’t spike stress hormones like cortisol and adrenaline. Instead of leaving you jittery and wired, it provides smooth, focused energy that works with your body—not against it. No stress overload, just clean, balanced alertness.

Break the Burnout Cycle

Caffeine gives you a temporary boost, but over time, it wears you down — creating a cycle of dependence and exhaustion. Px Coffee helps you stay energized without overstimulating your nervous system, so you can power through your day without running on empty.

More Restful Sleep

Px metabolizes faster than caffeine, so it won’t linger in your system and disrupt your sleep. That means you can enjoy coffee during the day without sacrificing deep, restful sleep at night. Wake up feeling truly refreshed.

Exceptional Taste

Great coffee should taste as good as it makes you feel.

We source high-quality beans and roast them to perfection, so you get the same rich, full-bodied coffee experience you love—with a smarter caffeine alternative.

Voted Best New Product by the Specialty Coffee Association in 2023, this is a brew you can depend on.

How to brew Px Coffee

Rarebird brews like traditional coffee. Brew it like you would your (old) favorite product. It can be drip-brewed, poured over, french-pressed, pulled (espresso), and even cold-brewed.

The serving size is 6g (or approx. 1 Tbsp), containing 60mg of Px. We recommend brewing 1-2 tablespoons per cup (6-8 oz.) of water, depending on how strong you like your coffee. For a standard 8-cup coffee maker, this is 1/2 cup of grounds.

Quality Testing & Science

Third Party Testing

We tested for mold and mycotoxins (ochratoxin and aflotoxin) to ensure quality and safety.

Certified Production

Roasted in GMP and FDA certified facilities in the U.S. and thoroughly tested for contaminants.

Rated 4.9/5 from 323 Reviews

Px Coffee

Dark Roast | 12 oz. Bag

A rich, bold roast with notes of dark chocolate, toasted marshmallow, and roasted nuts. Roasted fresh every week.

60mg Px per serving

Caffeine-like energy without the jitters

No afternoon crashes, sleepless nights

Rarebird Starter Pack | Two 12 oz. Bags

Our most popular selection. A month's supply of Px Coffee, allowing you to fully experience the benefits of replacing caffeine. Plus an extra 25% off.

60mg Px per serving

112 servings ($0.40/cup)

Caffeine-like energy without the jitters

No afternoon crashes, sleepless nights

Ground

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