Scientifically Proven, Performance Driven Rarebird replaces caffeine with Px, a smarter alternative naturally produced when your body metabolizes caffeine. The result? Clean, focused energy without the caffeine stress, jitters, or crashes. Px is even processed more efficiently, meaning it fades smoothly, helping you wind down and sleep better. Rarebird's patented, National Science Foundation-backed technology has enabled the creation of the first and only Px Coffee—a beverage designed to work with your body and help you perform at your best.