The monumental benefits of milk thistle seed (Silybum marianum) have been known for a good part of history. Used as a natural remedy for 2000+ years for its potential positive effects on the liver and gallbladder, milk thistle seed continues to be the go-to herb for liver health.
The ancient philosophers Pliny and Galen both recommended the herb for liver cleansing and support. Milk thistle seed is native to the Mediterranean area and some people call it Mary thistle and holy thistle. The stems of the milk thistle plant are regularly consumed by those in this area to help reduce oxidative damage in the liver and biliary tract.
Presently, milk thistle can be found in the United States growing wild in a variety of settings such as along roadsides and in backyards. If you are considering growing your own milk thistle, be aware that milk thistle is considered a highly invasive weed that spreads quickly…even to neighboring yards.
Silymarin in Milk Thistle Seed
The seeds of the milk thistle plant contain the highest amounts of the active compound, silymarin. Silymarin includes silybin, silydianin, and silychristin, and usually composes close to 4-6% of milk thistle seed. The most active compound in slymarin is silibinin which has been extensively used in patients with liver disease. When silymarin was used in animals it was discovered that it reduces liver injury caused by acetaminophen as well as showing positive effects in alcoholic liver disease, hepatitis and toxin-induced liver concerns. And currently, the safety record of milk thistle, when taken in recommended dosage range, is good with very minimal side effects such as a mild laxative effect. Serious toxicity as well as drug interactions have not been reported.
Note: Antioxidants like those found in milk thistle have been shown to possibly interfere with the efficacy of some chemotherapy drugs by protecting cancer cells from cell death. Understanding appropriate doses and examining blood concentrations is important before using milk thistle with chemotherapy. There is also a possibility that higher flavolignan concentrations in the gut could interfere with prescription medications. Ask your doctor for recommendations.
Not only is silymarin used to treat alcoholic liver disease, acute and chronic viral hepatitis and toxin-induced liver diseases, it has also been shown in animal studies to reduce liver injury caused by a number of drugs and environmental toxins, including acetaminophen (Tylenol), iron overload, amanita phalloides (the poisonous “death cap” mushroom), chemotherapy, psychotropic medications, phenylhydrazine, alcohol and carbon tetrachloride.
Health Benefits of Milk Thistle Seed
- Liver detoxification
- Support for healthy liver function
- Therapeutic treatment for fatty liver disease, damage from alcoholism, jaundice, psoriasis, hepatitis
- Boosts the immune system
- Supports healthy inflammation
- Supports heart health
- May help control symptoms of diabetes
- Helps support healthy gallbladder
- A potent inhibitor of UV-induced oxidative stress that can cause skin concerns
- Supports healthy skin and graceful aging
- Supports glutathione formation
- May help to regenerate liver cells
- Shows promise for stimulating cell regeneration in the kidneys and may prove useful even in patients on dialysis
- Exhibits antineoplastic effects
- Some research suggests, based on a number of pharmacological studies, that topical silymarin would be a beneficial addition to sunscreens in protecting against ultraviolet-B-induced skin cancers
- Supports healthy brain. May have potential as a neuroprotectant
- Animal studies suggest that silymarin may suppress the formation of amyloid beta-protein (toxic protein linked to Alzheimer’s), helping to prevent Alzheimer’s disease.
- Reduces cholesterol
- Reduces insulin resistance
- Milk thistle oil helps soothe concerns such as acne, eczema and rosacea
Side Effects of Milk Thistle
Milk thistle has a very gentle nature. When compared to other supplements and herbal remedies that come with side effects such as headaches, practically all parts of the milk thistle plant have been used with no toxicity reports. In clinical and lab studies adverse effects related specifically to the seed extract (silymarin) are also practically nonexistent, although milk thistle can have a mild and short-lived laxative effect for some people.
If you are experiencing any concerns about your liver or kidney health, or are interested in any of the potential health boosting properties of silymarin, a high-quality milk thistle supplement may be worth considering. Silymarin can also be found in artichokes, turmeric, and coriander (cilantro), although milk thistle is the richest known source.
- Polyak SJ, Oberlies NH, Pécheur EI, Dahari H, Ferenci P, Pawlotsky JM. Silymarin for HCV infection. Antivir Ther. 2013;18(2):141-7. doi: 10.3851/IMP2402. Epub 2012 Sep 25.
- Abenavoli L, Capasso R, Milic N, Capasso F. Milk thistle in liver diseases: past, present, future. Phytother Res. 2010 Oct;24(10):1423-32. doi: 10.1002/ptr.3207. Review.
- Aghazadeh S, Amini R, Yazdanparast R, Ghaffari SH. Anti-apoptotic and anti-inflammatory effects of Silybum marianum in treatment of experimental steatohepatitis. Exp Toxicol Pathol. 2011 Sep;63(6):569-74. doi: 10.1016/j.etp.2010.04.009. Epub 2010 May 14.
- Kidd PM. Bioavailability and activity of phytosome complexes from botanical polyphenols: the silymarin, curcumin, green tea, and grape seed extracts. Altern Med Rev. 2009 Sep;14(3):226-46. Review.
- Saller R, Meier R, Brignoli R. The use of silymarin in the treatment of liver diseases. Drugs. 2001;61(14):2035-63. Review.
- Rainone F. Milk thistle. Am Fam Physician. 2005 Oct 1;72(7):1285-8. Review.
- Ligeret H, Brault A, Vallerand D, Haddad Y, Haddad PS. Antioxidant and mitochondrial protective effects of silibinin in cold preservation-warm reperfusion liver injury. J Ethnopharmacol. 2008 Feb 12;115(3):507-14. Epub 2007 Oct 24.
- Vaknin Y, Hadas R, Schafferman D, Murkhovsky L, Bashan N. The potential of milk thistle (Silybum marianum L.), an Israeli native, as a source of edible sprouts rich in antioxidants. Int J Food Sci Nutr. 2008 Jun;59(4):339-46.
- Wojcikowski K, Stevenson L, Leach D, Wohlmuth H, Gobe G. Antioxidant capacity of 55 medicinal herbs traditionally used to treat the urinary system: a comparison using a sequential three-solvent extraction process. J Altern Complement Med. 2007 Jan-Feb;13(1):103-9.
- Ashfaq UA, Javed T, Rehman S, Nawaz Z, Riazuddin S. Inhibition of HCV 3a core gene through Silymarin and its fractions. Virol J. 2011 Apr 1;8:153. doi: 10.1186/1743-422X-8-153.
- Saller R, Brignoli R, Melzer J, Meier R. An updated systematic review with meta-analysis for the clinical evidence of silymarin. Forsch Komplementmed. 2008 Feb;15(1):9-20. doi: 10.1159/000113648. Review.
- Colturato CP, Constantin RP, Maeda AS Jr, Constantin RP, Yamamoto NS, Bracht A, Ishii-Iwamoto EL, Constantin J. Metabolic effects of silibinin in the rat liver. Chem Biol Interact. 2012 Jan 25;195(2):119-32. doi: 10.1016/j.cbi.2011.11.006. Epub 2011 Nov 25.
- Yaghmaei P, Parivar K, Masoudi A, Darab M, Amini E. The effect of silybin on passive avoidance learning and pathological changes in hippocampal CA1 and DG regions in male Wistar rats offspring. J Asian Nat Prod Res. 2009 Jun;11(6):514-22. doi: 10.1080/10286020902927864.
- American Botanical Council HerbClip, August 16, 2004.
- Biosci Biotechnol Biochem. 2010;74(11):2299-306.
- American Botanical Council December 31, 2007