Figure 1.

The factors limiting curcumin bioavailability and solutions. Poor solubility, low gastrointestinal absorption, and fast hepatic and intestinal metabolism are the main factors that constrain curcumin utilization by the human body. Studies on the delivery of curcumin in different formulations and metabolites of curcumin have been conducted to address these factors. Four strategies to address curcumin delivery are summarized in this review: lipid addition, absorption and dispersion on matrices, size reduction, and alterations to surface properties. Regarding the metabolites of curcumin, there are several reduced forms of curcumin, each of which can be conjugated to a sulfate group or glucuronic acid.