Calcium D-glucarate is the calcium salt of D-glucaric acid. In the stomach it forms D-glucaro-1,4-lactone, and that metabolite, not the salt itself, is the beta-glucuronidase inhibitor. Beta-glucuronidase reverses glucuronidation, the Phase II conjugation step that tags hormones and xenobiotics for excretion, so inhibiting it is the proposed route by which D-glucarate supports normal clearance of glucuronide-conjugated estrogens and xenobiotics. That mechanism is demonstrated in rodents. It has not been demonstrated in a controlled human trial. Marketed for estrogen metabolism support. Typical supplement labels carry 200-500mg/day, a range set by the market rather than by any published human dose-ranging study. D-glucaric acid occurs naturally in oranges, apples, grapefruit and cruciferous vegetables such as broccoli.