ConsumerLab Questions Quality of Milk Thistle Supplements

WHITE PLAINS, N.Y.Out of 10 milk thistle dietary supplements randomly selected for testing by ConsumerLab.com, only one met the organizations quality standards, according to its new report. According to the organization, two products failed to properly list the part of the plant that was used; after testing the remaining eight supplements using HPLC testing methods, only one contained the expected amount of silymarin, believed to be the active constituent in milk thistle. ConsumerLab reported most of the products purchased claimed the milk thistle extracts were standardized to 80 percent silymarin; however, actual amounts ranged from 47 percent to 67 percent. William Obermeyer, Ph.D., vice president for research, ConsumerLab.com, suggested manufacturers may be using non-specific tests, such as UV spectrophotometric analysis, that may count other compounds in determining silymarin content.

ConsumerLab includes the names of companies involved in the review in its general news release, but doesnt indicate which ones passed or failed testing, nor the levels of active ingredients in the products. However, the reports with complete findings are available for purchase from ConsumerLab.