What are the benefits of milk thistle?

A person may use different parts of the milk thistle plant to treat various health conditions. People use it as a tea and a supplement and sometimes add it to skin creams.

The most common use of milk thistle is for liver problems. Some people claim it can help to treat:

  • cirrhosis
  • jaundice
  • hepatitis
  • gallbladder disorders

Other potential benefits include protecting heart health by lowering cholesterol levels and helping people manage type 2 diabetes.

We explore the potential health benefits of milk thistle below.

Supports liver health

A 2016 study found that milk thistle improved diet-induced liver damage in mice. The medical community needs more evidence to prove that milk thistle benefits human livers in the same way.

However, researchers theorize that it does. The active ingredient in milk thistle, silymarin, acts as an antioxidant by reducing free radical production. Scientists think this creates a detoxifying effect, which is why milk thistle may be beneficial for liver problems.

Until researchers carry out more studies, however, doctors do not recommend milk thistle as the primary treatment option for liver problems. But it may be a helpful complementary treatment to try if a healthcare professional approves it.

Promotes skin health

Milk thistle may help to promote healthy skin. A 2015 study found that it helped to improve inflammatory skin conditions when applied to the skin of mice.

Researchers also found in another study that milk thistle had antioxidant and anti-aging effects on human skin cells in a laboratory environment. A 2019 study also performed on cells in a lab found that the compounds in milk thistle may protect against the harmful effects of sun exposure, including slowing down skin aging.

Researchers must carry out further studies on humans to identify what benefits a person can expect from applying milk thistle to their skin.

Reduces cholesterol

High cholesterol can lead to problems with heart health and increase a person’s chance of stroke. Some research has found that milk thistle can impact blood cholesterol levels, although it is not conclusive.

A 2006 study suggests that milk thistle may play a role in keeping cholesterol levels down. It found that cholesterol levels were lower in people taking milk thistle to treat diabetes than those taking a placebo.

In a 2016 study, researchers fed rats a high-cholesterol diet. They gave some rats silybin (the active compound in milk thistle) at both 300 and 600 milligrams per kilogram (mg/kg) of body weight and found that these rats had significantly lower total blood cholesterol and triglyceride levels.

Supports weight loss

Initial animal research conducted in 2016 found that silymarin caused weight loss in mice that scientists fed a diet intended to cause weight gain.

This suggests milk thistle may be beneficial for those looking to lose weight. Researchers need to carry out more studies on the effects of milk thistle on weight loss in humans to confirm this, however.

Reduces insulin resistance

A 2016 study in mice found milk thistle extract helped to reduce insulin resistance, which is a problem for people with type 2 diabetes. Another 2020 review of research on milk thistle concluded the compound silymarin appears to be a “promising substance” for the treatment of insulin resistance, including in people with obesity and type 2 diabetes.

Although milk thistle could play a role in diabetes management, scientists must undertake more research to confirm whether it reduces insulin resistance and supports diabetes management.

Improves allergic asthma symptoms

Asthma is a chronic inflammatory disease where the immune system overreacts to environmental triggers, leading to inflammation in the airways. The active ingredient in milk thistle may help to reduce inflammation.

A 2012 study found that silymarin helped to protect against inflammation in the airways of mice with allergic asthma. Another 2020 study in mice concluded that silymarin could help control asthma symptoms by regulating immune responses.

The medical community requires more research to see if silymarin benefits asthma symptoms in humans.

Limits the spread of cancer

Milk thistle may help to stop the spread of certain types of cancer.

Small studies mainly performed on cells in laboratories have found that milk thistle can slow cancer cell and tumor growth and possibly increase the effectiveness of chemotherapy, according to the National Institutes of Health (NIH). Researchers have found benefits for several types of cancer, including:

  • prostate cancer
  • breast cancer
  • cervical cancer
  • leukemia
  • skin cancer
  • colorectal cancer

Several small studies have also found that milk thistle may decrease the side effects of cancer treatments, including radiation, surgery, and chemotherapy.

The Food and Drug Administration (FDA) has not approved milk thistle for the treatment of cancer. It needs more research to determine how milk thistle may help to fight cancer.

Supports bone health

Milk thistle could play an essential role in supporting bone health. A 2013 study found that milk thistle helped to prevent bone loss.

The study looked specifically at bone loss caused by a deficiency in estrogen among rats that had their ovaries removed. It is not yet clear whether milk thistle is equally beneficial for bone loss with a different cause.

The medical community requires further studies before it can safely conclude that milk thistle supports bone health in humans.

Improves cognition

A 2015 study in worms found that milk thistle increased resistance to oxidative stress. Oxidative stress is a potential cause of Alzheimer’s disease.

In this way, milk thistle may help improve cognition and treat degenerative conditions that affect the mind. Researchers must carry out more studies on humans to confirm the effects of milk thistle on cognition.

Supports the immune system

Milk thistle may help strengthen a person’s immune response. It could help the body fight off infection as well as reduce chronic inflammation produced by the immune system.

Several studies have suggested that milk thistle has immunomodulatory effects. Researchers found silymarin stimulated the immune system. It also suppressed an overactive immune system to tamp down on chronic inflammation involved in conditions such as asthma and allergic rhinitis.

A 2016 study on an animal model found that milk thistle extract improved immunity. An older study found that milk thistle extract had a positive effect on immune response in humans.

More studies with human participants could allow scientists to say with certainty that milk thistle supports a person’s immune system.