Milk thistle has been used by traditional healers around the world for more than 2,000 years to support prostate, liver, and gallbladder health and more recently, scientists have started documenting the herb’s incredible health benefits.
What Is Milk Thistle?
Known sometimes as Mary thistle or holy thistle, and scientifically as Silybum marianum, milk thistle is a flowering plant originally from the Mediterranean region, although it has been brought to other regions, including North America. The prickly purple-flowering plant is in the sunflower or Asteraceae family. The plant was named milk thistle because of the milky white fluid inside of the stems, which is sometimes visible as white veins on the leaves. Milk thistle seeds, leaves, roots, young stalks, and flowers can be consumed for health benefits. Milk thistle can be purchased as a capsule, liquid supplement, or as a tea.
What Are the Active Compounds in Milk Thistle?
The extract of the milk thistle is called silymarin, and it contains several components, including silychristin, silydianin, and silybin (also called silibinin), which are flavonolignans. Silybin is the most abundant and most beneficial of the components, making up about 50 to 70 percent of silymarin.
How Does the Body Use Silymarin?
Silymarin has a bioavailability of around 30 to 50 percent; in other words, 30 to 50 percent of the flavonolignans get used by the body. Interestingly, when a healthy person consumes silymarin, the body converts it relatively rapidly to other chemical byproducts that do not have biological activity, with its peak activity occurring one to two hours after consumption. However, in patients with liver dysfunction, silymarin and the flavonolignans it contains stay in the blood longer and at concentrations three to five times higher than that of a healthy patient.
Silymarin, including its main component silybin, strengthens and stabilizes cell membranes, stimulates protein synthesis and cell regeneration in the liver, and prevents the production of prostaglandins that otherwise lead to irritation in the body.
How Milk Thistle Provides Liver Support
Milk thistle and its active components particularly help detoxify and support liver health. Milk thistle can counteract toxin-related damage and other conditions that produce redness and swelling. Milk thistle:
- Protects against toxic substances
- Protects against harmful organisms
- Promotes normal liver function
- Reduces iron overload in thalassemia patients
- Boosts glutathione levels
- May promote weight loss
The most-known and well-established health benefit of milk thistle is how it supports your liver. Silymarin directly blocks toxins that the liver encounters, preventing them from entering liver cells, thus preventing premature cell death. Silymarin is an antioxidant that soothes redness and irritation,[4, 5] provides a defense against various types of harmful organisms,[1, 2] and prevents the formation of scar tissue, or fibrosis, in the liver and elsewhere in the body.[1, 6]
Protects Against Toxic Substances
Milk thistle counteracts toxin-related injuries to the liver. Scientists have found that silymarin protects against liver damage from drug use, viral hepatitis,[1, 7] death cap (Amanita) mushroom poisoning,[2, 8] and acetaminophen.[1, 9] Over 80 percent of the liver is comprised of cells known as hepatocytes. Silymarin keeps toxic compounds from entering these cells, protecting them and, in turn, their contribution to liver function. It has helped support the liver in individuals exposed to high amounts of hydrogen sulfide. That’s an amazing variety of scientifically documented liver benefits for this purple flower!
Defends Against Harmful Organisms
Studies found that silymarin slowed and prevented infection in animals by preventing viral entry, fusion, and RNA and protein synthesis. Several small clinical studies found that silymarin given intravenously (in the veins) protected against viral proliferation in patients, and the treatment was well tolerated with no side effects. In other words, it stopped harmful organisms like viruses from spreading and growing.
Promotes Normal Liver Function
Because of the way it promotes normal liver tissue, milk thistle extract may help normalize liver function in people whose liver is challenged. In clinical studies on people with severe liver conditions, silymarin therapy normalized bilirubin levels, a yellow compound that comes from breaking down the heme in blood. Silymarin also normalized certain liver enzymes. As a result, silymarin-treated patients lived four years longer, on average, compared with those who did not receive it.
Reduces Iron Overload in Thalassemia Patients
Thalassemia is one of the most common genetic disorders worldwide. It results in anemia, or low blood levels of iron, requiring regular blood transfusions that can lead to iron toxicity and iron overload. Over a nine-month treatment, thalassemia patients given silymarin experienced better liver function and reduced iron overload as opposed to those using a placebo.
Boosts Glutathione Levels
Glutathione or GSH is known as the body’s super antioxidant, and it is abundant in the liver. Glutathione bonds with toxins in the body, making them too big to cross cell membranes. This effectively makes the toxins inactive — and easier for the body to transport them out through urine or feces. Silymarin from milk thistle boosts levels of glutathione, which helps the liver detoxify itself of harmful substances.[2, 12]
May Promote Weight Loss
One study in laboratory mice found that obese mice fed silymarin not only improved their liver function and reduced the circulating blood plasma lipids, it also led to a significant amount of weight loss (even when food intake remained the same) compared to mice not given the milk thistle compound. The jury is out on whether these weight loss results might apply to people.
Milk Thistle & Liver Detox
If you want to detoxify your liver, add milk thistle to your daily regimen. Whether you want to take a supplement or drink milk thistle tea, you should definitely consider the health benefits of this incredible herb. You can even try a full 5-day Liver Cleanse that includes eating a diet free of processed foods and toxins and taking a supplement that includes milk thistle. See our detailed Liver Cleanse Guide.
Milk Thistle Tea Recipe
The seeds of milk thistle are usually used to make tea. You can buy milk thistle seeds in bulk online or at many larger health food stores. You can also buy it in tea bags, already prepared.
To make milk thistle tea yourself follow these instructions:
- Tea infuser
- Milk thistle seeds
- Distilled water
- Pick a natural sweetener: Organic raw honey, agave, or stevia
- Crush one tablespoon of the seeds and place in a tea infuser with three cups of boiling water.
- Steep for about 10 minutes.
- Add raw honey, agave, stevia, or another natural sweetener, if desired.
Milk Thistle Safety & Side Effects
Milk thistle has an excellent safety record. The United States National Toxicology Program studied silymarin and found it to have no harmful effects on lab rats that consumed it daily for two years. In fact, the studies even found that milk thistle reduced the incidence of those rats getting liver tumors.
Milk thistle may have interactions with alcohol, anti-inflammatory drugs, antiretrovirals, estrogen, fertility agents, anti-anxiety drugs, and products used for heart, stomach or intestines. Check with your healthcare provider for further information and guidance about whether milk thistle is right for you.
Milk Thistle Dosage
While clinical studies have tested doses between 210 mg to 2100 mg daily, the typical and recommended dosage of milk thistle is 420 mg. You can drink up to six cups of milk thistle tea daily.
Best Milk Thistle Supplement
I recommend Livatrex®, our herbal liver support liquid supplement. It is a blend of raw herbal extracts including milk thistle seed, yellow dock root, chicory, and borotutu bark. It uses triple distilled water and vegetable glycerine as a base instead of alcohol, which can harm the liver.
Points to Remember
Milk thistle provides many benefits to your overall health, but specifically supports liver function and liver health. The herbal extract of milk thistle is called silymarin, and the main component of silymarin is silybin. Milk thistle provides an excellent, scientifically well-documented means to help boost your liver functioning. If you are concerned about your liver function or want to detoxify your liver, try a milk thistle supplement, milk thistle tea, or a full liver cleanse.
Is milk thistle part of your supplemental regimen? What benefits have you noticed?
- Polyak SJ, et al. "Hepatoprotective and Antiviral Functions of Silymarin Components in HCV Infection." Hepatology. 2013; 57(3),1262–1271.
- Kostek H, et al. "Silibinin and its hepatoprotective action from the perspective of a toxicologist." Przegl Lek. 2012;69(8),541-3.
- "Milk Thistle PDQ —Health Professional Version." National Cancer Institute, National Institutes of Health. Updated 17 Aug. 2018. Accessed 22 Aug. 2018.
- Ebrahimpour Koujan S, et al. "Effects of Silybum marianum (L.) Gaertn. (silymarin) extract supplementation on antioxidant status and hs-CRP in patients with type 2 diabetes mellitus: a randomized, triple-blind, placebo-controlled clinical trial." Phytomedicine. 2015;22(2),290-6.
- Liu W, et al. "Potent inhibitory effect of silibinin from milk thistle on skin inflammation stimuli by 12-O-tetradecanoylphorbol-13-acetate." Food Funct. 2015;6(12),3712-9. 6.
- El-Lakkany NM, et al. "Anti-inflammatory/anti-fibrotic effects of the hepatoprotective silymarin and the schistosomicide praziquantel against Schistosoma mansoni-induced liver fibrosis." Parasit Vectors. 2012;5,9.
- Schrieber SJ, et al "Differences in the disposition of silymarin between patients with nonalcoholic fatty liver disease and chronic hepatitis C." Drug Metab Dispos. 2011;39(12),2182-90.
- Abenavoli L, et al. "Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases." Phytother Res. 2018.
- Freitag AF, et al. "Hepatoprotective Effect of Silymarin (Silybum marianum) on Hepatotoxicity Induced by Acetaminophen in Spontaneously Hypertensive Rats." Evid Based Complement Alternat Med. 2015;2015,538317.
- Mandegary A, et al. "Hepatoprotective effect of silyamarin in individuals chronically exposed to hydrogen sulfide; modulating influence of TNF-? cytokine genetic polymorphism." Daru. 2013;21(1),28.
- Moayedi B, et al. "A randomized double-blind, placebo-controlled study of therapeutic effects of silymarin in β- -thalassemia major patients receiving desferrioxamine." Eur J Haematol. 2013;90(3),202-9.
- Alidoost F, et al. "Effects of silymarin on the proliferation and glutathione levels of peripheral blood mononuclear cells from beta-thalassemia major patients." Int Immunopharmacol. 2006;6(8),1305-10.
- Guo Y, et al. "Silymarin improved diet-induced liver damage and insulin resistance by decreasing inflammation in mice." Pharm Biol. 2016;54(12),2995-3000.
- National Toxicology Program."Toxicology and carcinogenesis studies of milk thistle extract (CAS No. 84604-20-6) in F344/N rats and B6C3F1 mice (Feed Studies)." Natl Toxicol Program Tech Rep Ser. 2011(565),1–177.
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.