Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers.
Level 3 - non-randomized controlled study
Non-randomized or unspecified comparative pharmacokinetic trial in humans alongside animal data
PubMed 9619120 · doi:10.1055/s-2006-957450
What was done
Researchers evaluated the effect of co-administering piperine (a known hepatic and intestinal glucuronidation inhibitor) on the pharmacokinetics and bioavailability of curcumin. Testing was conducted in rats (2 g/kg curcumin alone versus combined with 20 mg/kg piperine) and in healthy human volunteers (2 g curcumin alone versus combined with 20 mg piperine).
What was found
In rats, piperine co-administration increased serum curcumin concentrations 1 to 2 hours post-dose, significantly increased time to maximum concentration (P < 0.02), significantly decreased elimination half-life and clearance (P < 0.02), and increased bioavailability by 154%. In humans, 2 g curcumin alone produced undetectable or very low serum levels, whereas adding 20 mg piperine produced significantly higher concentrations between 0.25 and 1 hour post-dose (P < 0.01 at 0.25 and 0.5 h; P < 0.001 at 1 h), resulting in a 2000% increase in bioavailability with no adverse effects reported.
Why it matters
Curcumin has poor therapeutic utility when taken alone due to rapid intestinal and hepatic clearance. This study provides human and animal evidence that small doses of piperine substantially overcome this absorption barrier.
Limits
The abstract does not state the sample size (n) for either rats or humans. Participant demographics, randomization, blinding, exact baseline parameters, and pharmacokinetic tracking beyond the initial acute window in humans are not described in the abstract.
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