Piperine, by itself in the infamous 1998 and most quoted study, barely makes curcumin available for an hour. There is no valid existing scientific research that supports the use of piperine/bioperine in a capsule with curcumin. The famous "exploratory study" of the piperine and curcumin got very poor results. Very very important to notice in this socalled study of piperine (Black pepper extract) and it's alleged transport of curcumin are these facts:
(1)The study was flawed by the knowledge that a conflict of interest existed: the study was funded by a prominant manufacturer of piperine Sami Labs Ltd, Bangalore India. This is akin to the health research on cigarettes being funded by tobbacco manufacturers. This kind of funding calls the science into question.
(2) This was a single exploratory study in 1998 with no replicative studies to date according to the data bases. There are not likely to be any followup studies because the piperine failed to make curcumin bioavailable after an hour. In short piperine doesn't do it with curcumin.
(3) The increase in absorption only succeeded during the first hour. After that piperine-curcumin matched the lack of bioavailability of regular curcumin. This would make this approach ineffective. Maybe the supplement companies can pimp their one hour product as "Curcumin Fling".
(4) The socalled piperine-curcumin exploratory experiment was performed on only 6 human beings. That's right 6. That's a tiny sample and would never make the grade as scientific evidence.
(5) Supplement companies that promote this rubbish exploratory experiment, to back their hokum, need to really look at their research sources and their ethics.
(6) Piperine because of it's effects on the drug metabolism and it's potent anticoagulant activity ought to be taken with caution. Piperine is an irritant to the stomach and prostate. It's been used as a deadly rat and mouse poison. For many years piperine was also dabbed on kitty flea collars.
(7) While I don't claim to be any great shakes at math, I wonder about the claim that this study's piperine made curcumin 2000% more bioavailable. We know that by itself curcumin is not bioavailable save when taken with an oil or fat like what's done in Indian and Thai cooking and more recently with turmeric oil and fatty phosphatidylcholine experiments. With my logic turned on I can see where curcumin's bioavailability may be increased by 100%. That would be when all of it get's into our blood and organs. But 2000% is incredibly magical. That would mean the actual volume of the amount of curcumin was increased 20 fold. That would be akin to 1 gram of curcumin being magically turned into 20 grams of curcumin getting into your blood stream and organs. Perhaps these piperine-financed researchers from that medical college in Bangalore India have also studied the "psychic sciences" showing them how to "multiply substance" by 2000%. Maybe a translater produced a typo on the percentage. But know this: Many supplement companies make the expansive claim: Piperine makes curcumin 2000% more bioavailable. (All based on a single 1998 study, using injection rather than oral administration with no replication and failing anything more than an hour hangtime)
Science takes single exploratory studies with minimum of salt especially if they are funded by an organization that will sell this product. All too often the supplement companies play on the public imagination with single exploratory "studies". Often these studies are funded by organizations that stand to profit from positive outcomes, lack controls, lack humans, have far too small a sample or are flat out misreported.
Here's a fairly recent journal study of the challenges of curcumin bioavailability. They mention studies with fatty substances, with injected piperine/curcumin, and other substances.
http://curcuminresearch.org/PDF/Anand%20P-23.pdf