THE BASICS: Silymarin has traditionally been used as a remedy for liver disorders but has benefits in the treatment of diabetes, cancer, and toxic chemical exposures. It is the antioxidant extract from the seeds of milk thistle (Silybum marianum) and is far more potent than the whole seeds or unprocessed plant. Chemists classify silymarin as a flavonolignan, and it consists of several compounds, including silybin.

ALIAS: Silymarin supplements are sold in the form of standardized products, as well as in the form of milk thistle. It has been used for at least 2,000 years, including in ancient Greece and Rome.

HOW SILYMARIN WORKS: Silymarin works through several different mechanisms. First, as an antioxidant it quenches cell-damaging free radicals. Second, it suppresses the activity of tumor necrosis factor-alpha and interleukin-6, and therefore has anti-inflammatory properties. Third, it has cytoprotective (cell-protecting) benefits that have been demonstrated specifically in liver, pancreas, kidney, and
brain cells.

Silymarin Supplements Help with Hepatitis C Infection Marcella had received a blood transfusion 30 years ago, all but forgotten until she recently began experiencing persistent feelings of fatigue. Blood tests showed that she had elevated levels of alanine aminotransferase and aspartate aminotransferase, two enzymes that indicate liver disease. Subsequent tests showed that Marcella had chronic hepatitis C, a viral infection of the liver that likely was caused by a contaminated blood transfusion. (Blood used for transfusions is now tested for hepatitis.) Hepatitis C can lead to liver failure and death, and drug treatments (such as interferon) have serious side effects. A nutritionally oriented physician recommended that Marcella begin taking 400 mg of a standardized silymarin supplement. Within several weeks, her energy levels returned and her liver enzymes began to decrease.

HEALTH BENEFITS: Many of the benefits of silymarin center around its ability to maintain and enhance normal liver function.

• Liver disease. Silymarin has frequently been used to treat the liver complications of alcoholism, including cirrhosis. Excessive intake of alcohol or pharmaceutical drugs (including acetaminophen) injures liver cells and impairs liver function. In addition, obesity increases the risk of steatosis (fatty liver), which can impair this organ’s ability to break down chemicals. Chronic liver infections, such as hepatitis, also reduce liver function. Silymarin protects the liver by reducing inflammation, enhancing production of glutathione (an antioxidant), and stimulating the production of new liver cells by accelerating protein and DNA synthesis. Note: When liver cells are damaged, certain enzymes can leak out and enter the bloodstream. Elevated levels of these enzymes usually indicate liver damage.
• Diabetes. The liver works with the pancreas to regulate blood sugar, and elevated blood sugar levels (characteristic of diabetes) may reflect reduced function of both organs. Three studies of people with type 2 diabetes have found that silymarin supplements can help improve blood sugar and other markers of glucose intolerance. In one of the studies, 51 patients received 200 mg of silymarin daily for four months. The supplements led to a 15 percent decrease in blood sugar, a 25 percent drop in fasting insulin levels, and a 13 percent decrease in glycated hemoglobin levels. Glycated hemoglobin (HbA1c) reflects a six-week average blood sugar level. Another study found a 20 percent decrease in fasting blood sugar, a 37 percent decline in postprandial blood sugar, and a 16 percent decrease in HbA1c—plus an 8.5 percent reduction in weight. One other study found improvements in all markers of diabetes over the course of a year.
• Cancer. Silymarin may enhance the effectiveness of conventional cancer therapies while also lowering their toxicity. Human, animal, and cell studies have found that silymarin may be particularly helpful during the treatment of breast, ovarian, liver, and prostate cancers, according to reports in Integrative Cancer Therapies and other journals.
• Cell protection. Silymarin can reduce the toxic effects of chemical exposures, possibly by enhancing the liver’s ability to break down these chemicals. So far, researchers have found that silymarin can protect against carbon tetrachloride, toluene, and xylene.

BACKGROUND CHECK: Burt Berkson, MD, a nutritionally oriented physician in Las Cruces, N.M., developed a triple oxidant treatment of hepatitis C that includes silymarin, selenium, and alpha-lipoic acid. With this combination he has been able to consistently normalize liver enzymes in patients with the disease.

GLEANINGS: A recent study in Italy found that a combination of silymarin and vitamin E led to significant improvements in two groups of patients, those with hepatitis C infections and those with fatty liver. Silymarin reduced hepatitis C virus concentrations and liver enzymes in patients with hepatitis C. Meanwhile, patients with fatty liver had a decrease in liver enzymes, as well as in cholesterol, blood sugar, and inflammation.

HEADS UP: According to a report in American Family Physician, silymarin has no apparent drug interactions and rarely causes side effects.

WHAT YOU SHOULD TAKE: If you want to use silymarin to improve blood sugar, take 200 mg three times daily. However, if you take other supplements, such as chromium, lipoic acid, or N-acetyl-cysteine, you can likely lower the silymarin dose to 100 to 200 mg daily.

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Product Examples (from left to right)

A vegetarian formula, NOW Foods Silymarin milk thistle extract 150 mg also contains the herb turmeric, which has been shown to have liver-protective effects.

Also vegetarian-friendly, Nature’s Way Super thisilyn has 175 mg of silymarin. The formula also boasts artichoke, vitamin C, dandelion, turmeric, and other nutrients.

Eclectic Institute Milk Thistle 600 mg is a vegetarian formula containing the fresh, freeze-dried form of the herb. Each capsule has 24 mg, or about 4 percent, silymarin.