April 2013

Milk Thistle Studied For Hepatitis C

Milk thistle extract may not have significant effects on levels of alanine aminotransferase (ALT) in people who have chronic hepatitis C, a study reports.

ALT is an enzyme that is produced in higher amounts when the liver is inflamed, and may thus be a sign of hepatitis C. Hepatitis C is primarily spread via blood. It may also be transmitted through sexual contact and childbirth, although this occurs very rarely. Currently, there is no vaccine for hepatitis C. The only the way to prevent the disease is to reduce the risk of exposure to the virus. Individuals can minimize exposure to the virus by abstaining from sex, using protection during sexual contact, and not sharing needles.

Milk thistle has been used medicinally for over 2,000 years, most commonly for the treatment of liver and gallbladder disorders. A flavonoid complex called silymarin can be extracted from the seeds of milk thistle and is believed to be the biologically active component. The terms "milk thistle" and "silymarin" are often used interchangeably. Milk thistle products are popular in Europe and the United States for various types of liver disease. Although numerous human trials have been published, most studies have not been well designed or reported. Scientists recruited 154 people who had chronic hepatitis C infection and high ALT levels who had been previously unsuccessfully treated with interferon therapy. Interferon therapy is meant to boost the immune system and keep the virus from growing. The participants randomly received either 420 milligrams of milk thistle extract, 700 milligrams of milk thistle extract, or a matching amount of placebo given three times daily for 24 weeks. The research team measured ALT levels and quality of life.

After the treatment period, only two people in each of the two milk thistle groups had significantly reduced ALT levels. Significant differences in other measures, including quality of life, were lacking across all subjects.

The researchers concluded that milk thistle extract may lack significant effects on ALT levels in people who have hepatitis C, compared to placebo. However, more studies are needed before further conclusions can be made.

Numerous other integrative therapies have been studied as potential treatments for hepatitis C, including liver extract, safflower, and vitamin E. However, there is unclear or conflicting evidence for the use of these therapies in hepatitis C. More research is needed.

For more information about milk thistle, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Fried MW, Navarro VJ, Afdhal N, et al. Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trial. JAMA. 2012 Jul 18;308(3):274-82. doi: 10.1001/jama.2012.8265. 
  2. Natural Standard: The Authority on Integrative Medicine. 

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