One product had an unacceptable amount of lead and six products did not contain expected amounts of silymarin compounds, which are believed to be the active constituents of milk thistle.
Studies suggest silymarin may be helpful in type 2 diabetes, certain liver conditions, and may protect the liver from toxic effects of chemotherapy.
While most products claimed that their milk thistle extracts were standardized to 80% silymarin, ConsumerLab.com found actual amounts to range from 48% to 67%.
Sales of milk thistle in the U.S. were $108 million in 2011, up 10.2% from the prior year according to the latest figures from Nutrition Business Journal.
The FDA does not set standards for the quality of herbal supplements nor specify how they must be tested. Consumers normally have no way of knowing which form they purchase other than from ConsumerLab.com‘s independent reports.
ConsumerLab.com‘s Product Review of Milk Thistle Supplements can be found at www.consumerlab.com/results/milkthistle.asp. The report provides information on how to choose and use these supplements as well as test results, quality ratings, and product comparisons for the following eleven supplements selected for testing by ConsumerLab.com:
- Bluebonnet Herbals Milk Thistle Extract
- Dr. Whitaker Milk Thistle Liver Cleanse
- Jarrow Formulas Milk Thistle Extract 30:1
- Natrol Milk Thistle Advantage
- Natural Factors Milk Thistle Extract 80% Silymarin
- Nature’s Plus Milk Thistle Extended Release
- NutriCology Phyllanthus Complex
- Pure Encapsulations Silymarin Milk Thistle Extract
- Rainbow Light Milk Thistle Plus
- Shaklee Liver DTX Complex
- Trunature (Costco) Milk Thistle
ConsumerLab.com is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. Reviews of other popular types of supplements are available from www.consumerlab.com. Subscription to ConsumerLab.com is available online. The company is privately held and based in Westchester, New York. It has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products.