Recently, the US Food and Drug Administration proposed a ban on over-the-counter
hydroquinone mainly on the basis of high absorption, reports of
exogenous ochronosis in humans, and murine hepatic
adenomas, renal
adenomas, and
leukemia with large doses over extended time periods. Systemic exposure to
hydroquinone from routine topical application is no greater than that from quantities present in common foods. While murine hepatic
adenomas increased, murine
hepatocellular carcinomas decreased, suggesting a protective effect. Renal
tumors are sex, species, and age specific and therefore do not appear relevant to humans after decades of widespread use. Murine
leukemia has not been reproducible and would not be expected from small topical doses. Finally, a literature review of
exogenous ochronosis and clinical studies employing
hydroquinone (involving over 10,000 exposures under careful clinical supervision) reveal an incidence of
exogenous ochronosis in the United States of 22 cases in more than 50 years. Therefore, the proposed ban appears to be unnecessarily extreme.