Milk thistle is a flowering herb that some people may consider using as a home remedy to help treat various health conditions, including cancer. Milk thistle and extracts of milk thistle, such as silymarin, are rich in antioxidants and may have some medical uses. However, more research is necessary to prove its effectiveness.

Research is exploring silymarin and milk thistle and their potential use as a breast cancer treatment alongside traditional therapies to either protect cells or reduce potential side effects.

However, milk thistle is not for everyone, as there may be some risks involved. More human studies are necessary to determine whether or not it is effective. Anyone who is looking to use milk thistle for any health condition should consult a doctor first.

This article discusses whether or not milk thistle can help with breast cancer treatment. It also looks at some potential risks and benefits associated with the herb.

A jar that contains milk thistle oral capsules.Share on Pinterest

Milk thistle may have some health benefits, mainly thanks to the extract silymarin and its active compound silybin, or silibinin.

Research from 2019 notes that silymarin and silybin have antioxidant and anti-inflammatory properties. The compounds may help repair and prevent damage in cells, which is an important factor in many conditions — including cancer.

That said, researchers note that silymarin is not very bioavailable, meaning that the body cannot use it very easily. This is why some people may make a complex of silybin with phosphatidylcholine to create phosphatidylcholine-bound silybin. This increases its bioavailability.

Research from 2020 notes that silymarin may have roles in preventing cell damage leading to cancer and reducing side effects in healthy cells from cancer treatments.

For example, the compounds in milk thistle appear to counteract the toxic effects on the kidneys caused by some chemotherapy agents common in breast cancer treatment, such as cisplatin. This is important. These chemotherapy drugs are highly effective, but doctors currently need to limit their use due to these toxic effects.

Researchers also note that silymarin may have a synergistic effect with some anticancer drugs to help kill some types of cancer cells, including breast cancer cells. This could mean that it may have use as a potential pre-treatment before other therapies for cancer.

Milk thistle may also help reduce side effects from other cancer treatments. The National Cancer Institute (NCI) notes that in small human studies, applying a cream containing silymarin to the skin helped prevent rashes from radiation therapy in people with breast cancer.

That said, the research is preliminary. More studies in humans may help find better ways to use the compound. Currently, there is not enough evidence to recommend milk thistle as a treatment for cancer.

Milk thistle is a common name for the plant Silybum marianum, which is native to Europe. It has large, prickled leaves with white veins running across them. The active extract of milk thistle is silymarin, which is extractable from the plant and seeds.

Milk thistle comes in a few different forms. Extracts of milk thistle containing higher levels of active ingredients may come in the form of oral capsules, oral tablets, tinctures, or other liquid extracts.

Milk thistle and its active compounds contain antioxidants that may help protect cells and offer some benefits to the body.

There are several potential benefits of milk thistle, thanks to the high antioxidant profile of the extract silymarin.

For example, milk thistle may help protect the liver and its cells. Research from 2019 notes that milk thistle and silymarin have had medical uses for liver disease and gallbladder conditions for thousands of years.

Although further research is still necessary, silymarin may also have medical uses for a few other conditions, including those affecting the:

  • pancreas
  • bile duct
  • kidneys
  • myocardium
  • central nervous system

It may also have potential anti-diabetes actions, as it may help with insulin resistance. However, results are currently mixed, so more research exploring this potential benefit can help clarify whether or not milk thistle is helpful for this purpose.

Until further research confirms that milk thistle is beneficial, people should continue using the current medical treatment options available to them.

Milk thistle is generally safe to use. The NCI notes that side effects from silymarin are rare but can include:

At high doses (over 1,500 milligrams per day), some people may have mild allergic reactions to silymarin. People who have allergies to similar plants, such as chrysanthemum and marigold, may also have allergic reactions to milk thistle.

In addition, some other groups may need to be wary of milk thistle. For example, there is not enough information about the safety of using milk thistle while breastfeeding or pregnant.

There may also be some drug interactions to consider. Research from 2019 notes that the low bioavailability of silymarin makes many drug interactions unlikely, but there are some exceptions, and drug interactions can occur.

Therefore, it is advisable to speak with a doctor before using milk thistle alongside drugs that affect the liver, hormones, or cholesterol, as there may be interactions. People with diabetes should also consult a doctor before using the herb. Milk thistle may lower blood sugar levels, which could affect medication use or dosage.

Safety and regulation may also be an issue for some milk thistle products. The Food and Drug Administration (FDA) has not approved the use of milk thistle as a treatment for cancer.

Additionally, the FDA does not regulate dietary supplements in the same way as it regulates food and drug products. As a result, the exact amounts of a compound or other ingredients in any given batch may vary. Because of this, people should also only use silymarin or milk thistle from a trustworthy company.

Silymarin and milk thistle generally come in forms that are easy to use.

For oral formulations, people can consider either working with a doctor to find a safe personal dosage or following the general dosage from the instructions on the packaging.

For topical formulations containing silymarin or milk thistle extract, people can apply an appropriate amount to the skin.

There are several herbs rich in antioxidants that may also possess anti-inflammatory actions. These may help support the body and protect cells in a similar way to milk thistle, but it is important to note that none are a treatment option for cancer.

Some antioxidant-rich herbs and foods include:

Learn more about natural treatments that may help with breast cancer here.

Milk thistle contains helpful antioxidants and may have anti-inflammatory properties. These properties could make it a useful adjunct therapy to use alongside traditional therapies for breast cancer.

However, research on the topic is preliminary, so more clinical trials in humans may help expand on these possibilities. There is currently not enough evidence to recommend it for use in any type of therapy for cancer.

Anyone who is curious about whether or not milk thistle may be right for them can discuss this with a doctor. Each case of breast cancer is different, and doctors may have different recommendations for each person to help prevent side effects or make treatments more effective.