Turmeric Interactions

Curcumin, the main active in turmeric, has antiplatelet activity and may also inhibit CYP2C9 metabolism of warfarin, raising warfarin levels. New Zealand Medsafe issued an alert in 2018 after a patient's INR rose above 10 within weeks of starting a turmeric/curcumin product on previously stable warfarin therapy.

Piperine, the active alkaloid in black pepper, inhibits hepatic and intestinal glucuronidation of curcumin and other compounds, and a landmark human study reported a 2000% increase in curcumin bioavailability when 20 mg piperine was co-administered with 2 g curcumin. This is one of the most cited absorption-enhancement combinations in the supplement literature.