WARNING: Extremely potent and spicy. Keep away from eyes.
What Is Piperine?
Piperine is the main active component found in black pepper.
Piperine can be used in conjunction with various other supplements to enhance their potency by increasing bioavailability. The most apt example of this synergy is taking piperine while supplementing with curcumin. Curcumin has a very poor bioavailability because it is rapidly metabolized in the liver and intestinal wall. Piperine can slow both gastric emptying and intestinal transit, meaning that curcumin has a longer period of time to be exposed to potential uptake. One study found that piperine supplementation increased the bioavailability of curcumin by 2000%.  Another study found that piperine supplementation also improved the bioavailability of resveratrol.* 
Piperine inhibits the drug transporter P-glycoprotein as well as the major drug-metabolizing enzyme CYP3A4.  This is important because many drugs are substrates of these enzymes, meaning that these enzymes break down many drugs; when these enzymes are inhibited they are unable to do so and so the drugs last longer and are able to be absorbed more by the body.*
It is recommended to start at a low dose of 5-10mg daily and see how your body reacts before increasing dosage.
Synonyms: Piper Nigrum, Black Pepper Extract