Milk Thistle Tea: Benefits, Side Effects, and Dosage

The milk thistle plant (Silybum marianum) is part of the Asteraceae family and is native to the Mediterranean.

Its name comes from the milky white veins on the leaves and the white sap they produce when broken. The plant’s flowers are purple (2).

Milk thistle is also known as Saint Mary’s Thistle, holy thistle, variegated thistle, and Scotch thistle. In folk tradition, the white veins on its leaves were said to come from a drop of the Virgin Mary’s breast milk that spilled on them (3).

The plant’s milky sap and rumored connection to Mary’s milk are two reasons why some people believe it can stimulate breast milk production (4).

Throughout history, milk thistle has also been used to treat liver and gallbladder issues. Research has also explored its potential to protect against neurodegenerative diseases, cancers, diabetes, and heart disease (1, 3).

Milk thistle is available as capsules, tablets, liquid extracts, and tea. The plant’s seeds and sometimes leaves are used in these preparations.

Milk thistle tea has a mild taste comparable to that of dandelion tea.

Summary

Milk thistle is a plant with white-veined leaves that has traditionally been used to treat liver issues and stimulate breast milk production, among other applications. In addition to tea, it’s available as oral pills and extracts.

The main group of active compounds in milk thistle is known as silymarin. The main component of this group is called silybin (2).

Though silymarin is present in the flowers and leaves of the thistle, it’s most concentrated in the seeds (2).

The purported health benefits of milk thistle are thought to be connected to silymarin’s antioxidant properties.

Silymarin may exhibit antioxidant effects by scavenging and preventing the formation of reactive molecules called free radicals that can contribute to cell damage and disease development. It may also decrease inflammatory responses in your body (5).

Since milk thistle teas are often made with ground or whole seeds, they provide some silymarin, but they’re not as concentrated as extracts.

What’s more, milk thistle is poorly absorbed and not water-soluble. Thus, drinking this tea is not the best way to absorb any beneficial plant compounds (6, 7).

Summary

The main beneficial compounds in milk thistle tea are collectively known as silymarin. Silymarin has antioxidant properties, which is why it may have health benefits.

Existing studies on milk thistle have been small or poorly designed or have produced mixed results. What’s more, the limited research has focused on extracts and pills, both of which are more concentrated than tea (8).

As such, any promising effects of milk thistle preparations noted in existing studies may not apply to diluted milk thistle tea, especially when considering the plant’s low water solubility and poor absorption.

Keep this in mind when reviewing the following possible benefits of milk thistle.

Liver health

The most studied benefit of milk thistle is its potential to promote liver health.

Some studies suggest the plant may help with management and treatment of viral hepatitis, alcohol-related liver disease, non-alcohol-related fatty liver disease, liver cancer, and liver injuries caused by drugs or toxins (9).

However, it has not been found to protect against the onset of these liver conditions (9).

While it remains unclear how milk thistle may affect your liver, it’s believed that silymarin extracted from the plant may have anti-inflammatory, antioxidant, and antiviral effects (10).

For example, one review found that silymarin may extend the life expectancy of people with cirrhosis due to alcohol-related liver disease, possibly by protecting the liver from free radicals produced during alcohol metabolism (11).

There’s also speculation that milk thistle extracts and isolated forms of silymarin can improve markers of inflammation and liver damage in people with certain liver diseases, although studies have been inconclusive (3, 12, 13).

Ultimately, more research is needed to better understand the effectiveness and safety of milk thistle preparations, including teas, in treating liver diseases.

Breastfeeding

Milk thistle is thought to increase levels of the hormone prolactin and thereby boost milk supply in people who are breastfeeding (4).

However, there are almost no clinical studies that assess this claim — and none on milk thistle tea in particular.

One randomized controlled trial in 50 lactating women found that those who took 420 mg of silymarin, the active compound in the plant, each day for 63 days produced more than 60% more milk than those who took a placebo (14).

Still, more studies are needed to assess the safety and effectiveness of using milk thistle supplements or tea during lactation. Speak with a healthcare professional before trying the plant while breastfeeding (8, 15).

Diabetes

Milk thistle is also being investigated for its potential anti-diabetic effects (16).

A systematic review found that silymarin supplements significantly reduced fasting blood sugar levels in people with diabetes. However, the reviewers noted that the available studies were low quality and that more research is needed (17).

Milk thistle may help with blood sugar control by improving insulin sensitivity and decreasing inflammation associated with diabetes (18).

Even though the results from existing research are promising, larger, well-designed studies are needed to investigate the use of these extracts and teas in diabetes management.

Summary

Limited research suggests milk thistle may help in the treatment of liver diseases, stimulate breast milk production, and have anti-diabetic effects. However, there are no studies on milk thistle tea in particular.

There is no standardized dosage or recommended intake for milk thistle tea, but it’s generally considered safe if consumed in moderation.

Milk thistle supplements, for reference, are tolerated at doses of up to 700 mg, 3 times per day for 24 weeks (1).

Possible side effects of the plant include stomach upset, nausea, and diarrhea (1).

Due to a lack of research on milk thistle tea use in people who are pregnant or breastfeeding, you should speak with a healthcare professional before trying it if you’re in either of those groups (8).

Milk thistle may lower blood sugar levels. So, if you have diabetes, you should be cautious about consuming tea or supplements made from the plant (8).

Finally, if you have allergies to plants in the same family, such as ragweed, chrysanthemum, marigold, and daisy, you may be at risk of allergic reactions and should proceed with caution (8).

Summary

Milk thistle tea is considered safe in moderation. However, if you are pregnant or breastfeeding, have diabetes, or have allergies to plants in the same plant family, you should use caution or avoid milk thistle tea.

Milk thistle tea is easy to make at home. It’s available for purchase as loose or ground seeds and leaves or in tea bags.

Steep a tea bag or 1 teaspoon of loose tea in 1 cup (237 mL) of hot water for 5–10 minutes. If not using a tea bag, strain the tea before drinking it.

Summary

You can make milk thistle tea at home by steeping 1 teaspoon of loose tea or a tea bag in hot water for 5–10 minutes before straining.

Milk thistle tea is an herbal drink touted to promote liver health, stimulate breast milk production, and protect against diabetes.

However, there have been no studies on milk thistle tea specifically, and research on other preparations — such as isolated forms of the active compound silymarin — is limited. Milk thistle may also be poorly absorbed in tea form.

If you still want to explore the possible benefits of milk thistle tea, it’s easy to make at home. Just keep in mind that more research is needed to understand its effectiveness and safety.