A great deal of research has been conducted using this herb for a variety of liver diseases, although research specifically targeting the hepatitis C virus has not found an antiviral effect. Three ingredients in milk thistle are of scientific interest because of their potential therapeutic value and capacity to protect the liver. These ingredients are silibinin, silychristin, and silydianin, collectively known as silymarin. The evidence is promising regarding the use of milk thistle for upset stomach and diabetes. The evidence is inconclusive at this point regarding milk thistle's potential to treat various liver diseases. Further hepatitis C studies are currently underway.
Attention for Liver Disease: The Hepatitis C Antiviral Long-Term Against Cirrhosis (HALT-C) study reported that silymarin was associated with reduced symptoms, but not reduced liver inflammation when used by HCV patients. May lower liver function tests. Because it appears to interact with cytochrome p-450 metabolized substances (see Cytochrome P-450)>, do not take milk thistle during HCV treatment especially if taking Olysio (simeprevir) combination therapy.
Interactions: May interact with any cytochrome p-450 metabolized substances (see Cytochrome P-450). Silymarin has the potential to interact with many drugs, herbs and dietary supplements. A few are hormones, methadone, antibiotics, anti-seizure, antidepressants, antipsychotics, antihistamines, organ transplant-rejection, cardiac, lipid- lowering drugs and sleeping pills.
Lab Notes: May alter liver function tests and blood sugar levels.
Note: The biggest issue with milk thistle is that the quality varies tremendously among products and what is available may be of poor quality. Research- grade milk thistle is difficult to find in the U.S.