Px is what caffeine isn't
Every bit of energy, focus, and performance.
All without the side-effects.
But what is Px?
First let's address the elephant in the room. It's a lot easier to pronounce than it looks:
pair - uh - zan - theen
Px (short for paraxanthine) is the primary human metabolite of caffeine—a condensed way just to say "the main substance your body turns caffeine into."
In nature, it can be found in very small amounts in some foods, including coffee beans, Theobroma cacao fruits, citrus flowers, and Sicilian orange flower honey. However, it primarily exists inside our bodies while processing caffeine.
Because Px is derived from caffeine, it has many of the same benefits—increased alertness, reduced fatigue, and decreased drowsiness. However, the natural differences between them make Px much less likely than caffeine to cause negative side effects, including “jitters”, anxiety, irritability, and nervousness.
Benefits beyond energy
Recent studies (both by Rarebird and by independent researchers) on paraxanthine have shown many potential benefits of Px:
AS SEEN IN
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
Rarebird's Story
"Like millions, I relied on caffeine to get through the day—until I realized it was a crutch. Instead of giving me energy, it left me anxious and burned out. When I couldn’t find a better alternative, I was forced to make one. Px Coffee was born from a simple idea: energy should work with your body, not against it."
- Jeffrey, Founder & CEO
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.
Is Px Coffee right for you?
Px Coffee offers benefits whether you drink decaf or regular, one cup or 5.
For Decaf Drinkers
Px provides a cleaner, better energy than caffeine. But because Px is more specialized and easier for your body to process, it won't make you jittery and overstimulated.
For "1-2 Cuppers"
Caffeine gives you a morning boost but anything more (and anything past noon) and jittery all afternoon and up all night. Px allows you to wake up energized, re-up with an afternoon cup, and still sleep soundly at night.
For "Coffee-holics"
You process caffeine ok, but there's not really a boost after the first or second cup; chances are your afternoons are unfocused and foggy and you wake up after sleeping 8 hours feeling like you only slept 6. That's because A) caffeine doesn't stack and B) still affects the quality of your sleep. Px's efficient metabolism and fewer off-target side-effects mean that unlike with caffeine, each cup should work for you, not against you, and get processed before you go to bed so that 8 hours means 8 hours.
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 4.9/5.0 from 345 reviews
Dark Roast | 12 oz. Bag
Our most popular roast. Rich and bold with notes of dark chocolate, toasted marshmallow, and roasted nuts.
60mg Px per serving
Caffeine-like energy without the jitters
No afternoon crashes, sleepless nights
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Benefits Over Time
Day 1: First cup. Only energy, no crash.
Week 1: Better sleep, better focus.
Month 1: Peak performance every day.
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.
Is Px Coffee right for you?
Px Coffee offers benefits whether you drink decaf or regular, one cup or 5.
For Decaf Drinkers
Px provides a cleaner, better energy than caffeine. But because Px is more specialized and easier for your body to process, it won't make you jittery and overstimulated.
For "1-2 Cuppers"
Caffeine gives you a morning boost but anything more (and anything past noon) and jittery all afternoon and up all night. Px allows you to wake up energized, re-up with an afternoon cup, and still sleep soundly at night.
For "Coffee-holics"
You process caffeine ok, but there's not really a boost after the first or second cup; chances are your afternoons are unfocused and foggy and you wake up after sleeping 8 hours feeling like you only slept 6. That's because A) caffeine doesn't stack and B) still affects the quality of your sleep. Px's efficient metabolism and fewer off-target side-effects mean that unlike with caffeine, each cup should work for you, not against you, and get processed before you go to bed so that 8 hours means 8 hours.
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.
WIRED not... Wired
"Honestly, I felt many of the positive effects after my first cup. I felt focused and got a lot of work done, certainly more than I would have if I didn’t have any coffee at all, and I got absolutely none of the heart-racing, jittery feeling I do with regular coffee. Even if you drink a lot of this, you’re not going to feel cracked out, but your attention span will likely increase. It’s a weird biohack, but it works. Another bonus—I didn’t feel it rush through my digestive system as I do with good regular coffee, if you know what I mean."
— Andrew Watman, Wired
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