Liver Health and Cirrhosis

Silymarin, an active component of milk thistle, may improve liver function and reduce symptoms of cirrhosis, or scarring of the liver. However, the evidence is conflicting.

One study questioned the benefits of milk thistle for liver diseases. Eighteen clinical trials of 1,088 participants were assessed. Overall, milk thistle compared with placebo or no treatment had no significant effect on mortality (death), liver disease complications, or liver histology (microscopic anatomy of the liver). Further, while liver-related mortality was significantly reduced by milk thistle, this was not seen in any of the high-quality trials.4

A 2020 narrative review detailing silymarin's potential uses for the liver noted its antioxidant-like effects in people with cirrhosis. The review went on to say that silymarin may be linked to lower rates of mortality in patients with cirrhosis and liver disease.5

Other studies looking at milk thistle for cirrhosis have found conflicting results. Therefore, it is not known whether milk thistle or silymarin should be used to treat cirrhosis.

What Is Silymarin?

Silymarin is an active component of milk thistle, which is not found in foods. Milk thistle supplements containing silymarin are commonly sold as teas or in capsule form, but are also available as tablets, soft gels, and liquid extracts. Some, but not all, milk thistle supplements are vegan.

 3 Herbal Remedies for Liver Health

Hepatitis C

People sometimes use milk thistle for hepatitis C, a viral infection of the liver.

A survey conducted in the U.S. reported that 23% of those polled used herbal supplements for their hepatitis C, with milk thistle being the most common choice. The survey revealed anecdotal evidence of the improved quality of life among those who took milk thistle, despite having no measurable improvements in hepatitis symptoms like liver inflammation.6

A study from 2012 confirmed that milk thistle might not have true beneficial effects on hepatitis C. In the study, patients who took silymarin, an active component of milk thistle, daily for 24 weeks had no significant improvements in liver enzymes or other measures compared to those who took the placebo.7

Although milk thistle may be helpful in hepatitis C, more research is needed to support these claims.

Type 2 Diabetes

Several studies have suggested that milk thistle may be beneficial for people with type 2 diabetes.

In one such study, a 45-day course of silymarin, the active component of milk thistle, increased antioxidant capacity and reduced generalized inflammation in adults with type 2 diabetes compared with a placebo. According to researchers, these findings suggest that silymarin may improve diabetes symptoms like oxidative stress and inflammation.8

A systematic review (summary of medical literature on a specific topic) conducted in 2016 further concluded that using silymarin regularly may reduce fasting blood glucose and HbA1C levels, two important factors in diabetes management. However, the review's authors warned that the quality of the studies was poor and that more research is needed before milk thistle should be recommended for use.9

 Natural Remedies for Diabetes Prevention

Breast Milk Production

Milk thistle often is used as a galactalogu, a food or supplement that people who are chest feeding take to improve milk production. Trigonellafoenum-graecu (fenugreek) also is used for this reason.

The benefits of milk thistle remain unclear for this purpose and the limited research on milk thistle and breast milk has been done primarily in animals. One small clinical trial showed an increase in breast milk formation in humans using milk thistle, but researchers caution that more studies are needed.10

Cancer

The research on milk thistle's use in cancer patients is promising, although more research is needed to determine its benefits. Studies on cancer cell lines (done in the laboratory) have found that elements in milk thistle:11

• Boost the impact of chemotherapy drugs like cisplatin and doxorubicin when treating ovarian and breast cancer
• Have direct benefits against prostate, breast, and certain cervical cancer cells
• Do not stimulate the growth of leukemia cells
• Can be used to complement treatment for liver cancer12
  

Researchers also are looking at how milk thistle might complement traditional care and treatment in people diagnosed with gastrointestinal cancers.13

 The 4 Stages of Cervical Cancer

Skin Health

Milk thistle is sometimes used to treat skin conditions including mild psoriasis.14 It's also proven useful in treating skin that's been damaged by radiation during breast cancer treatment.

Milk thistle products appear to help the skin heal from damage caused by UVB radiation from the sun and may offer benefits in preventing non-melanoma skin cancers.15 In some cases it may be useful in treating these cancers, but studies have yet to fully demonstrate the safety and efficacy of milk thistle use.

 Symptoms of Skin Cancer

Bone Health

Some researchers have suggested milk thistle benefits when treating osteoporosis after menopause, and it's a commonly used supplement in the U.S. There's limited evidence, though, for the role of milk thistle in bone health.10

However, one area of milk thistle research focuses on how it affects bone marrow, which contributes to overall bone health but also has implications in treating diseases like multiple myeloma, a type of blood cancer.16