Hepatotoxicity

Herbal and dietary supplements make up a measurable share of cases. A 2017 review, written from a research symposium sponsored by the American Association for the Study of Liver Disease and the National Institutes of Health, reported that supplement-induced liver injury accounts for 20% of hepatotoxicity cases in the United States, based on research data [1]. The major agents implicated were anabolic steroids marketed as bodybuilding supplements, green tea extract and multi-ingredient nutritional supplements [1]. Most cases are now due to multi-ingredient products, where the component responsible is usually unknown or can only be suspected [1].

The two levels in the definition matter. LiverTox, the liver-injury reference from the US National Institutes of Health, separates enzyme rises seen on blood tests during use from clinically apparent liver injury, and rates agents with a likelihood score [2]. Its ashwagandha entry, for example, reads "B (likely cause of clinically apparent liver injury)" [2].

Trial results alone may not settle the question. The same LiverTox entry notes that clinical trials of ashwagandha reported no serum enzyme elevations, while cases of clinically apparent liver injury were later reported in people taking commercial products [2]. Because commercial herbal preparations are often mixtures and can be mislabeled, LiverTox says it is not always clear whether a reported case was due to the herb itself or to a contaminant [2].

NootropicsWork safety sections report the LiverTox likelihood score where an entry exists, and a score of A to C counts toward a compound's safety flag. Liver findings on a compound page describe what the sources report about that compound, and readers with questions about their own liver health are referred to a clinician.

• Adverse event
• Interaction
• Cytochrome P450