Formulation-dependent dissolution and bioaccessibility of curcuminoids and (S)-ar-turmerone from eight commercial turmeric extract- and curcumin-containing dietary supplements

CONTEXT: Curcumin-containing dietary supplements are widely marketed with claims of enhanced bioavailability, despite well-recognized limitations related to poor aqueous solubility, chemical instability, and extensive first-pass metabolism. Comparisons among commercially available products using physiologically relevant performance metrics remain limited. OBJECTIVE: To systematically evaluate disintegration, dissolution, and bioaccessibility of curcuminoids and (S)-ar-turmerone from a cross section of commercially available turmeric dietary supplements under fasted- and fed-state biorelevant conditions. MATERIALS AND METHODS: Eight marketed turmeric supplements representing diverse formulation strategies were assessed for disintegration and dissolution using USP-aligned methods in fasted- and fed-state simulated gastric and intestinal media (FaSSGF, FaSSIF, FeSSGF, FeSSIF). Bioaccessible concentrations, quantities, and dose fractions of curcuminoids and (S)-ar-turmerone were quantified after 3 h. RESULTS: All products exhibited poor dissolution overall, with no formulation achieving greater than 40% total release. Dissolution was lowest under fasted-state conditions and improved modestly in fed-state gastric media, reflecting the influence of lipid content. Products with higher curcuminoid loads per capsule generated greater absolute bioaccessible concentrations despite poor release efficiency, whereas a phytosome formulation achieved superior release despite a lower dose. Several products marketed as "enhanced" formulations demonstrated poor disintegration and low bioaccessibility. DISCUSSION: These findings indicate that bioaccessible concentration is governed jointly by dosage-form performance and curcuminoid dose loading, and that plasma exposure metrics dominated by conjugated metabolites may not reliably reflect formulation performance. CONCLUSION: release is a prerequisite - but not a guarantee - for enhanced systemic exposure, underscoring the need for cautious interpretation of bioavailability claims.