A 2026 review published in Pharmaceutical Biology investigated how often turmeric products contained unlisted or misleading ingredients. The authors analyzed data from 48 global studies, covering more than 2,200 turmeric samples. They found that approximately one in five products were adulterated.

Turmeric marketed as a culinary spice was frequently diluted with fillers like corn starch or colored with synthetic dyes to enhance its visual appeal, compromising its quality and effectiveness. In parts of South Asia, turmeric powder was colored with lead-based compounds, posing serious health risks, especially for children. Natural turmeric supplements were most commonly tainted with synthetic curcumin. Countries with stricter regulations and enforcement mechanisms had lower rates of adulteration. For example, the adulteration rate in the United States and Canada was 14.9 percent.