Quercetin-d3 hydrate is a deuterated form of quercetin hydrate, known as a flavonoid that stimulates recombinant SIRT1 and acts as a PI3K inhibitor. It has IC50 values of 2.4 µM, 3.0 µM, and 5.4 µM for PI3Kgamma, PI3K delta, and PI3Kbeta, respectively.