Piperine

Piperine is an alkaloid and the main pungent constituent of black pepper (Piper nigrum) and long pepper; chemically it is a piperidine alkaloid built around a piperidine ring and a benzodioxole group, with the formula C17H19NO3 ^[1]. It makes up a substantial fraction of pepper, roughly 5 to 10 percent of black pepper and a smaller share of long pepper, and it was first isolated by the Danish chemist Hans Christian Ørsted in 1819 ^[1]. Several isomers exist, some of which are tasteless.

The familiar heat of pepper comes from piperine's action on sensory nerves: it activates the TRPV1 receptor, the same channel responsible for the burn of chili peppers, which the body registers as a sharp, pungent sensation ^[1].

Piperine's most distinctive and heavily studied role, however, is as a bioavailability enhancer, or bioenhancer, a substance that increases the absorption and blood levels of other compounds taken with it ^[3]. It does this by interfering with the body's mechanisms for breaking down and expelling foreign molecules: it inhibits several drug-metabolizing enzymes, including cytochrome P450 isoforms, blocks the efflux transporter P-glycoprotein that pumps substances out of intestinal cells, and slows conjugation reactions such as glucuronidation ^[1][3]. The best-known example is its pairing with curcumin, the active pigment of turmeric, which on its own is very poorly absorbed; a landmark study in human volunteers reported that piperine raised curcumin's bioavailability dramatically, and this effect is the basis of the branded ingredient sometimes sold as a black pepper extract for use in supplements ^[2]. Other strategies, such as encapsulating curcumin in nanoparticles, have been compared with piperine as alternative ways to improve its absorption ^[4].

Beyond enhancing absorption, piperine has shown antioxidant, anti-inflammatory, immunomodulatory, and anticancer activities in laboratory and animal studies, though piperine itself has limited bioavailability ^[1]. It is used as a spice component and dietary supplement; in the amounts found in food it is considered safe, but its enzyme-inhibiting property means it can alter the levels and effects of medications taken alongside it ^[1].

At the small doses used for absorption enhancement it is well tolerated, with occasional GI irritation. The real concern is drug interactions: because it inhibits the same enzymes and transporters that clear many medications, it can raise blood levels of drugs and other supplements, sometimes meaningfully. Anyone on prescription medication should be cautious with piperine-containing products.