The milk thistle (Silybum marianum) is a plant indigenous to southern Europe, but can now be found throughout Europe and North America.
The extract of milk thistle has been used for millennia to treat a range of conditions, particularly disorders of the liver and kidneys.
Contemporary research has focused on understanding the therapeutic effects of organic milk thistle extract, which contains high levels of a compound called silymarin. Silymarin is comprised of a number of flavonolignans and flavonoids, which exhibit antioxidant properties.
Silymarin or milk thistle is commonly used as an herbal supplement. Although it has not shown significant actions against chronic liver disease, S. Marianum has been observed in laboratory tests to exhibit anticarcinogenic (chemopreventive) and anti-inflammatory properties.
Routine supplementation with organic milk thistle may help protect the liver and kidneys from accumulated toxicity stemming from drug use – particularly in the case of chemotherapy drugs.
Use of S. Marianum as a dietary supplement is generally well tolerated and has been used across cultures for thousands of years. Within recommended dosages, it has only been shown to cause a mild laxative effect, some gastrointestinal upset and rare cases of allergic reactions.



- Supports liver health & detox
- Anti-oxidant & anti-inflammatory properties
- Improves insulin sensitivity & cholesterol
Organic Milk Thistle
Related Topics
- Milk Thistle
- Silybum Marianum
- Silymarin
- Benefits & Uses
- User Reviews
- Use for Diabetes
- Use for Hangovers
- Use for Psoriasis
- Use for Liver Health
- Use for Weight Loss
- Milk Thistle Tea
- Milk Thistle Extract
- Dosage Guide
- How to Take
- Reported Side Effects
- Safe Usage
- Best Supplements
- Combo with Dandelion Extract
- Milk Thistle Tincture
The main active ingredient in milk thistle is a flavonolignan complex called silymarin.
Silymarin is the name for a group of flavonoids and flavonolignans, including silibinin (composed of silybin A and sylibin B), silychristin (silichristin) and silydianin (silidianin).
These phytochemicals have been under clinical scrutiny for decades, and are thought to protect against liver toxicity, various cancers and chronic disease of the liver.
While preliminary studies have provided some promising results, there are insufficient rigorous clinical studies (controlled studies on a human population) to determine any specific healing and/or preventative properties of organic milk thistle.
As a consequence, although milk thistle is commonly used in holistic medical practices, it has not been fully incorporated into standard Western medicine.
How Does Milk Thistle Work?
Organic milk thistle extracts contain concentrated amounts of silymarin flavonolignans. Flavonolignans are natural phenolic compounds which are part lignan (which exhibit anti-estrogenic and antioxidant properties) and part flavonoid (which play a role in cell signaling and exhibit antioxidant properties).
In both animal and in-vitro experiments, silibinin molecules have demonstrated hepatoprotective (liver protecting) properties. Also, during in-vitro tests, silibinin has been observed to exhibit anticancer actions against human prostate, estrogen-dependent breast, estrogen-independent breast, ectocervical, lung and colon cancer cells.
Also, silibinin from organic milk thistle is being tested for its use against the effects of poison, particularly the hepatotoxic (liver damaging) effects of “Death Cap” (Amanita phalloides) mushrooms. Further, preclinical studies have generated evidence that silibinin supports treatment of liver cirrhosis stemming from alcohol abuse.
Milk Thistle for Liver Health and Protection
In one study from 2012, organic milk thistle supplementation improved symptoms of hepatocellular carcinoma – the most prevalent form of liver cancer.
Liver function was enhanced by stabilizing liver cell membranes, scavenging ROS (reactive oxygen species), stimulating apoptosis (cell death), inhibiting fibrogenesis and promoting hepatocyte (liver cell) regeneration. No serious or lasting adverse side effects were noted.
Concerning its hepatoprotective attributes, organic milk thistle has been observed to:
- Regenerate liver cells damaged by alcohol, pharmaceuticals and other toxic substances;
- Decongest the liver, allowing bile to flow more freely through the gallbladder and liver;
- Reduce bile-stimulated liver damage and gallstone formation;
- Increase survival rates of patients with advanced cirrhosis
Milk Thistle and Cancer Research
While the hepatoprotective effects of organic milk thistle have been studied since the 1960s, research addressing its possible anticancer and chemopreventive effects has only occurred over the past decade.
Silybum marianum has been observed to selectively promote the death of cancerous cells and regulate cell cycle activity.
In various human prostate cancer trials, silymarin flavonoids from organic milk thistle have been observed to support cancer prevention and intervention.
Milk thistle has been observed to improve glucose utilization and cholesterol synthesis. It is being studied for its ability to alleviate symptoms of type II diabetes mellitus and heart disease.
Dosage Guidelines
Phase 1 clinical trials have been completed examining the potential toxicity of milk thistle supplements. Daily doses as high as 13 grams were observed to be well tolerated in subjects with late-stage prostate cancer.
The most prevalent side effects were asymptomatic liver toxicity conditions including elevated aminotransferase levels and/or hyperbilirubinemia (jaundice). Additionally, there seems to be no toxicity induced on embryos in animal experiments.
Safety and Side Effects
As is the case with numerous other flavonoids, silymarin inhibits cellular efflux when mediated by P-glycoprotein. Regulating P-glycoprotein actions may change the bioavailability and absorption of P-glycoprotein substrate pharmaceuticals. Silymarin is known to slow down the actions of P450 cytochrome enzymes. The possibility of negative interactions with P450 cytochrome substrates cannot be excluded.
Organic milk thistle is generally well tolerated. However, it is important to adhere to the recommended dosages provided by extract manufacturers. In all cases, be sure to speak with your doctor before taking organic milk thistle supplements.
- Post-White J1, Ladas EJ, Kelly KM. Advances in the use of milk thistle (Silybum marianum). Integr Cancer Ther. 2007 Jun; 6(2):104-9.
- Brantley, Scott J. et al. "Two Flavonolignans from Milk Thistle (Silybum Marianum) Inhibit CYP2C9-Mediated Warfarin Metabolism at Clinically Achievable Concentrations." The Journal of Pharmacology and Experimental Therapeutics 332.3 (2010): 1081–1087. PMC. Web. 8 Aug. 2015.
- Rosso N1, Marin V, Giordani A, Persiani S, Sala F, Cavicchioli L, Rovati LC, Tiribelli C. The pros and the cons for the use of Silybin-rich oral formulations in treatment of liver damage (NAFLD in particular). Curr Med Chem. 2015 Jul 29.
- Ebrahimpour Koujan S1, Gargari BP2, Mobasseri M3, Valizadeh H4, Asghari-Jafarabadi M5. 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 Feb 15;22(2):290-6.
- Deep, Gagan et al. "Angiopreventive Efficacy of Pure Flavonolignans from Milk Thistle Extract against Prostate Cancer: Targeting VEGF-VEGFR Signaling." Ed. Surinder K. Batra. PLoS ONE 7.4 (2012): e34630. PMC. Web. 10 Aug. 2015.
- Abenavoli L Non-alcoholic fatty liver disease and beneficial effects of dietary supplements. World J Hepatol. 2015 Jun 28;7(12):1723-4.
- Bosch-Barrera J1, Menendez JA2. Silibinin and STAT3: A natural way of targeting transcription factors for cancer therapy. Cancer Treat Rev. 2015 Jun;41(6):540-6.
Article last updated on: April 28th, 2018 by Nootriment