Silymarin is the active component extracted from the seeds of the milk thistle plant.
Milk thistle and silymarin extract has been used for centuries in European and Asian cultures to treat a variety of digestive ailments and diseases of the liver.
The main therapeutic agent in milk thistle is a compound comprised of several flavonoids and flavonolignans, collectively called silymarin. Flavonoids are known antioxidants and silymarin has been observed to exhibit antioxidant action.
According to research, silymarin extract helps protect the liver against the damage caused by free radicals. Free radicals are compounds that cause oxidation and destruction of healthy cells, which is suspected to play a role in the development of some disease.
Silymarin has been observed to increase the production of antioxidant enzymes that help protect the liver, such as superoxide dismutase (SOD), as well as catalase and glutathione.



- Supports liver health & detox
- Anti-oxidant & anti-inflammatory properties
- Improves insulin sensitivity & cholesterol
Why Use Silymarin Extract?
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The liver is one of the largest glands in the body. Its primary function is to filter waste products, toxins and other damaging substances from the blood.
Milk thistle extract (silymarin) has played a significant role in traditional healing systems to support liver function and health.
The antioxidant effects of silymarin not only impact the liver, but the whole body. However, silymarin extract is primarily used to protect the liver and is often taken to reduce the toxic effects of alcohol, drugs and other damaging substances.
Milk thistle has been used for more than 2,000 years as a treatment for a variety of ailments, particularly diseases of the liver and gallbladder. The first recorded use of milk thistle was in Ancient Greece when the plant was used to treat a poisonous snake bite.
Silymarin has been identified as the therapeutically active constituent of milk thistle. Traditionally silymarin could only be obtained by extracting it from the seeds of milk thistle, but today it can be found as a standardized mixture of flavonolignans.
Reported Benefits of Silymarin Extracts
This compound is currently being investigated for its potential efficacy in treating a variety of liver conditions and diseases, as well as some cancers, including prostate, breast and skin cancers.
Studies to date have mainly relied on cell cultures and animals. Human studies remain inconclusive regarding the long-term effects of silymarin extract in the treatment of certain disorders.
Although human studies are limited and inconclusive, silymarin has been observed to prevent cell apoptosis (death) in laboratory tests. In animal studies it has also been observed to reduce cellular damage caused by free radicals and slow the progression of alcohol-induced disease, including cirrhosis of the liver and hepatic fibrosis (excessive build up of connective or scar tissue on the liver).
The herb has also been studied for its impact on blood insulin levels and as a supporting treatment for those diagnosed with cirrhotic diabetes.
Using Silymarin Extract Supplements
Silymarin extract contains approximately seven flavonolignans as well as polyphenols. One of the most active compounds in silymarin is silibinin.
In addition, the combination of silibinin and phosphatidycholine (the main ingredient in soy lecithin) is thought to enhance the absorption, allowing silibinin to be immediately delivered to tissues within the digestive tract.
Concentration of silymarin can vary from product to product. You can check for the percentage of silymarin found in silymarin extract products. For example, 175 mg capsules can be standardized to provide 80% silymarin, providing up to 140 mg the compound in every capsule.
In general, doses of silymarin may range from 200 mg to 800 mg a day. Dosage and potency of silymarin tablets may differ widely between manufacturers and brands, so be sure to follow the manufacturer’s dosage instructions.
Silymarin Extract Side Effects
Silymarin is available in a variety of forms and in a number of different products. When taken correctly and under the guidance of a physician, silymarin extract is generally well tolerated by humans.
However, dosage, indications, and contraindications depend on the individual’s age, overall health and wellness, contributing medical factors and other considerations.
Individuals with ragweed allergies should not take milk thistle or silymarin because of the potential for a serious allergic reaction. You should check with your doctor about possible contraindications and interactions before using this supplement.
This is especially important for individuals who have been diagnosed with a medical condition and are taking prescription medications.
Silymarin is associated with few serious side effects, but studies involving individuals taking the herbal supplement for more than 41 months are lacking. Be aware that milk thistle or silymarin extract may cause mild and temporary diarrhea, and has also been associated with temporary bloating, gas, upset stomach and nausea.
Certain individuals should use caution when supplementing with milk thistle. This includes individuals previously diagnosed with a medical condition. Be sure to speak with a medical professional before starting any supplement program.
Always consult with the pediatrician or obstetrician when considering silymarin extract or other supplements during pregnancy or when breastfeeding.
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Article last updated on: May 4th, 2018 by Nootriment