where would one be able to get grapefruit extract or Naringin?
im interested in peperine as well, but are there extracts available (from pepper?)
Extracts are available in small quantities from places like iherb or beyond-a-century dot com.
These work by competitive depletion of the enzymes needed to metabolize other substances. Many piperidine supplements are merely ground black pepper in a capsule. Watch your stomach lining. Grapefruit and its juice contain enough naringenin to slow the metabolization of many drugs, which makes the half-life longer, so they have a greater effect. Other drugs act through their metabolites, slowing their formation will inhibit the action of the substance or drug.
One does not need extracts, drinking grapefruit juice or using ground pepper will have the effect, though perhaps not so precisely as an extract.
Some formulators add these to enhance bioavailability, but it's a shotgun approach; they will affect other things one consumes, perhaps unfavorably. Luteolin, like querectin, has been shown to increase serum levels of resveratrol (and they occur in peanuts and grapefruit) but may also block its metabilic effect on Sirt1. No one knows with certainty, there are not enough studies, and individuals' enzymatic phenotype may mean different people will have different effects.
AFIK no studies have been done with piperidine and resveratrol.
