How Long Does Milk Thistle Stay In Your System

How Long Does Milk Thistle Stay In Your System?

Milk thistle (MT), or Silybum marianum, has been revered for its medicinal properties for centuries. It's commonly used for liver and gallbladder disorders, as well as for detoxification and general health. A query that garners significant interest from numerous individuals is how long does milk thistle stay in your system. In this article, we will explore the answer to this question together.

Before exploring further, please read the disclaimer located at the end of this webpage.

Key Takeaways

  • The milk thistle plant takes approximately one day to be completely eliminated from the body.
  • Its half-life is about 6-8 hours.
  • The milk thistle plant demonstrates effectiveness in both short-term and long-term scenarios.
  • It may take at least 6 months to observe the long-term benefits of the milk thistle plant.
  • The duration the milk thistle plant remains in the body and the time it takes to exhibit effects depend on factors such as age, weight, absorption rate, and frequency of use.

How Long Does Milk Thistle Stay in Your System?

How long does milk thistle stay in your system

The half-life of milk thistle is approximately 6-8 hours, and it may take around 30-40 hours for it to be completely eliminated from the body.

In addition, a study evaluated the absorption and metabolism process of components in milk thistle in 14 volunteers. The study observed that most silymarin compounds, the main constituents of Milk Thistle, were predominantly excreted within 24 hours. Therefore, the period during which Silymarin is absorbed into the body may be within one day after consumption. [5]

However, the duration for milk thistle to exit your system can vary based on age, weight, liver function, and the dosage and frequency of milk thistle consumption.

How Long Does it Take for Milk Thistle to Work?

The time it takes for milk thistle to work can vary depending on the individual and the condition being treated. Some people may experience benefits within a few weeks, while others may need to take it for several months before seeing results.

A study titled "Review of Clinical Trials Evaluating Safety and Efficacy of Milk Thistle (Silybum marianum [L.] Gaertn.)" examined placebo trials on Milk Thistle over the past 5 years and observed its effectiveness in both short-term and long-term trials. [4]

Some short-term trials assessing Milk Thistle's efficacy for liver diseases over 4 weeks, such as Torres et al.'s study (2004) using 160mg of Milk Thistle three times a week for 4 weeks, reported potential efficacy in reducing inflammation.

However, there was no apparent effect on viral load.[4]

Conversely, studies conducted over more extended periods noted higher efficacy, with most positive results documented after more than 24 weeks of experimentation.[4]

This data suggests that Milk Thistle may start showing its effects at least a few weeks to a month into usage. An extended 6 to 8 months may be necessary to achieve optimal effectiveness. However, these figures are mere conclusions based on the trial durations of these studies, as the time for Milk Thistle to take effect varies for each individual.

Milk Thistle Metabolism

When you consume milk thistle, it goes through a lot of changes as it travels through your digestive system. The first changes happen in the small intestine, where any sugar parts are removed.

The remaining compounds then undergo processes that make them easier for your body to handle, such as being combined with other substances. Once these processed compounds enter your bloodstream, they may go through additional changes in the liver and other organs [3].

Milk Thistle Benefits


Antioxidant property of milk thistle

The active complex of MT is an extract derived from the plant's seeds. It consists of three flavonolignan isomers, namely silybin, silydianin, and silychristin, collectively known as Silymarin.

Silymarin is an excellent antioxidant, scavenging free radicals (reactive oxygen species) and inhibiting lipid peroxidation, thereby protecting cells against oxidative stress. It can protect the liver, brain, heart, and other vital organs from oxidative damage for its ability to prevent lipid peroxidation and replenish the reduced glutathione levels.[1]


Milk thistle seeds have been used to protect the liver since ancient times. Silymarin in milk thistle seeds safeguards liver cells from toxins and enhances their regenerative ability. It is effective in managing liver damage caused by ingesting mushrooms and other substances. Silymarin also provides support in cases of food poisoning and defends the liver against various diseases. [1]

It is for therapy of hepatitis A, alcoholic cirrhosis, and chemically induced hepatitis. Silymarin's antioxidant and hepatoprotective properties from milk thistle benefit patients with alcoholic cirrhosis and acute viral hepatitis. It also promotes liver tissue regeneration and exhibits potential for reducing fibrosis.[1]

Blood (plasma) lipidaemic control

Blood (plasma) lipidaemic control of milk thistle

Administering Silymarin to type II hyperlipidemic patients slightly lowers total cholesterol and high-density lipoprotein levels in blood plasma. Silymarin may decrease liver cholesterol synthesis, making it a potential agent for managing hypercholesterolemia and atherosclerosis.[1]

Biliary effect

Silymarin in milk thistle goes through excessive enterohepatic circulation, creating a continuous loop between the intestine and liver. It prevents bile secretion disturbance, leading to increased bile secretion, cholate, and bilirubin excretion.[1]

Anti-viral effect

Anti-viral effect of milk thistle

Although Silymarin doesn't affect viral replication, it plays a beneficial role in viral hepatitis by inhibiting inflammatory and cytotoxic processes induced by viral infection. Silymarin in milk thistle also exhibits inhibitory activity against various viruses in different cell lines.[1]

Ways to Clear Milk Thistle from Your System

Drink Water

Staying hydrated by drinking plenty of water can support the natural elimination of substances from the body. Water helps flush out compounds through urine and supports overall kidney function.


Regular physical activity, such as exercise, can promote blood circulation and metabolic processes, potentially aiding in eliminating substances from the body.

Healthy Diet

A well-balanced diet focusing on fruits, vegetables, and fiber can contribute to overall health and assist in the body's natural detoxification processes.

Milk Thistle Cycling

The cycling approach is often employed to prevent the development of tolerance or desensitization to the herb's effects and maximize its potential benefits. The rationale behind cycling supplements, such as milk thistle, is the concern that the body may adapt to continuous exposure, potentially reducing the herb's effectiveness over time.

The body can reset its responsiveness by taking breaks from its use, leading to a more robust response when the supplement is reintroduced. In one study, participants were given Silymarin at 420 mg/day (divided into 3 doses) for 12 weeks, with a 2-week washout period between treatments. The treatment was well-tolerated, with no reported adverse effects.[6]


The most straightforward way to clear milk thistle from your system is to stop taking it. If you've been using milk thistle supplements, the active compounds will gradually diminish once you cease consumption.


Milk thistle is a robust plant with many health benefits, especially for the liver. It's effective in treating various liver conditions due to its active compounds called Silymarin. The time it takes to see results from milk thistle can vary depending on the person and condition being treated.

While its half-life is around 6-8 hours, complete elimination from the body can take about 30-40 hours, depending on factors like age, weight, liver function, and dosage. Staying hydrated, exercising regularly, eating a healthy diet, and consuming can aid in its elimination. However, it's always recommended to consult a healthcare provider before starting or stopping using milk thistle or other supplements.


  • [1] Bhattacharya, Sanjib. “Phytotherapeutic Properties of Milk Thistle Seeds: An Overview.” Journal of Advanced Pharmacy Education & Research, vol. 1, 2011, pp. 69–79, Accessed 16 Jan. 2024.
  • [2] Abenavoli, Ludovico, et al. “Milk Thistle in Liver Diseases: Past, Present, Future.” Phytotherapy Research, vol. 24, no. 10, 7 June 2010, pp. 1423–1432,
  • [3] Calani, Luca, et al. “Absorption and Metabolism of Milk Thistle Flavanolignans in Humans.” Phytomedicine, vol. 20, no. 1, Dec. 2012, pp. 40–46, Accessed 24 Apr. 2022.
  • [4] Tamayo, C. (2016). Review of Clinical Trials Evaluating Safety and Efficacy of Milk Thistle (Silybum marianum [L.] Gaertn.) - Carmen Tamayo, Suzanne Diamond, 2007. Integrative Cancer Therapies.
  • ‌[5] Luca Calani, Brighenti, F., Bruni, R., & Daniele Del Rio. (2012). Absorption and metabolism of milk thistle flavanolignans in humans. Phytomedicine, 20(1), 40–46.
  • [6] “Milk Thistle Uses, Benefits & Dosage - Herbal Database.”, Accessed 19 Jan. 2024.
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Ralph S. Albert, with over 10 years of expertise in nutrition and research, now heads the Research division at Vinatura Supplements. His dedication and extensive knowledge ensure top-quality articles on nutrition and health, collaborating with a skilled team. He has successfully completed The VINATURA Expertise Research Training Program, underscoring his commitment to Vinatura's mission. Ralph has also published numerous articles and conducted valuable research in the field, making him a trusted resource for individuals on their wellness journey.

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