Only traces of degradation compounds of 1 appear in the blood during the time when most of the curcumin is excreted in the feces. Owing to poor absorption of 1 into the bloodstream, piperine (4) has been recommended to enhance the curcumin absorption by 20-fold . However, this approach of metabolic inhibition is neither specific for 1, nor does it enhance 1 titers enough to reach pharmacologically relevant levels.