Milk thistle ( Silybum marianum ), also known as silymarin , is a medicinal plant that has been used for centuries to support liver health. Extract from milk thistle seeds is particularly rich in silymarin, a group of flavonoids known for their liver-protective and antioxidant properties. Whether used to promote liver function, protect against liver damage, or support digestion, milk thistle extract is a versatile natural remedy that is particularly valued for liver disease. In this article, you'll learn all about milk thistle, its health benefits, and how to best use it.
What is milk thistle?
Milk thistle is a plant belonging to the daisy family ( Asteraceae ) and is native to the Mediterranean region. The seeds of the plant contain the active ingredient silymarin, a group of flavonolignans that give milk thistle its liver-protective properties. Silymarin acts as a powerful antioxidant, protecting liver cells from free radical damage. Milk thistle extract is commonly used in supplements to support liver health, detoxification, and digestion [1].
Synonyms for milk thistle
Milk thistle is also known as silymarin , Silybum marianum , milk thistle, or medicinal thistle . Its main active ingredient, silymarin, is often the main ingredient in dietary supplements used to support liver health. The extract is available in capsule, tablet, or tea form [2].
Where does milk thistle come from?
Milk thistle is native to the Mediterranean region but grows in many regions of the world, including Europe and North America. It has been used in traditional medicine for centuries, particularly for the treatment of liver diseases and digestive problems. Today, milk thistle extract is used worldwide as a dietary supplement to protect the liver and support detoxification [3].
How is milk thistle extract produced?
Milk thistle extract is obtained from the seeds of the milk thistle plant, which are dried and processed into a powder. The main active ingredient, silymarin, is isolated using a special extraction process to ensure the highest concentration of liver-protecting compounds. This extract is then used in dietary supplements such as capsules, tablets, or teas [4].
Health benefits of milk thistle
Milk thistle and liver health
Perhaps the most well-known benefit of milk thistle is its ability to support liver health. Silymarin, the main active ingredient in milk thistle, protects liver cells from toxins and free radicals that can cause liver damage. It is commonly used to treat liver diseases such as fatty liver disease, cirrhosis, and hepatitis. Studies show that silymarin promotes liver cell regeneration and may slow the progression of liver damage caused by alcohol consumption or medications [5].
What's really good for your liver? Learn more about the effects of acetylcysteine (NAC) on the liver and lungs in this article: Acetylcysteine (NAC) – Antioxidant for Liver & Lungs .
Milk thistle and detoxification
Milk thistle also plays an important role in detoxifying the body. The liver is the primary detoxification organ, and milk thistle supports its function by increasing the production of glutathione, a powerful antioxidant. Glutathione is essential for detoxifying heavy metals, pesticides, and other pollutants that can accumulate in the body. By supporting liver function, milk thistle extract helps rid the body of toxins and promote overall health [6].
Milk thistle and skin health
The antioxidant properties of milk thistle may also benefit the skin. By supporting the body's detoxification process, milk thistle extract helps cleanse the skin from within and reduce the appearance of blemishes such as acne or eczema. Silymarin also protects skin cells from damage caused by free radicals and UV radiation, helping to prevent premature skin aging [7].
Milk thistle and cholesterol
Milk thistle may also help lower cholesterol levels. Studies show that silymarin can lower LDL ("bad") cholesterol and increase HDL ("good") cholesterol. This makes milk thistle a potential agent for supporting heart health and reducing the risk of cardiovascular disease [8].
Milk thistle and digestion
Milk thistle has traditionally been used to support digestion. It can help stimulate bile production, which aids fat digestion and relieves digestive discomfort such as bloating and fullness. Milk thistle extract is often used for people with bile problems and other digestive disorders [9].
How does milk thistle work in the body?
Milk thistle extract works by stabilizing liver cells and promoting the regeneration of damaged liver cells. Silymarin, the main active ingredient, acts as an antioxidant and protects liver cells from free radicals and toxins. Silymarin also increases glutathione production, which supports liver detoxification. Milk thistle also improves bile secretion, thus supporting digestion and fat processing in the body [10].
Recommended dosage and use of milk thistle extract
What is the recommended dosage?
The recommended dosage of milk thistle extract depends on the intended use, but typically ranges from 140 to 420 mg of silymarin per day, divided into two to three doses. To support liver health, a dosage of approximately 200 mg of silymarin per day is often recommended. Higher doses may be used for more severe liver disease or for detoxification. It is recommended to take milk thistle extract with food to improve absorption [11].
When should you take milk thistle extract?
Milk thistle extract can be taken at any time of day, ideally with meals to optimize absorption. When used to support liver health or for detoxification, regular intake over a longer period is recommended for optimal results. Milk thistle can also be taken preventively to maintain liver function, especially in people who regularly consume alcohol or take medication [12].
Side effects and safety of milk thistle extract
Is milk thistle extract safe?
Milk thistle extract is considered very safe and well-tolerated, even with long-term use. No serious side effects have been identified in clinical studies. However, people with allergies to plants in the daisy family (such as daisies or chamomile) should be cautious, as milk thistle may cause allergic reactions. Pregnant and breastfeeding women should consult a doctor before taking milk thistle [13].
What are the side effects of milk thistle extract?
Rare side effects of milk thistle extract include mild gastrointestinal disturbances such as diarrhea, flatulence, or nausea. In rare cases, allergic reactions may occur, especially in people sensitive to plants of the daisy family. It is recommended to reduce the dosage if these side effects occur or to consult a physician [14].
Milk thistle compared to other ingredients
Milk thistle vs. artichoke extract
Both milk thistle and artichoke extract support liver function and digestion. While milk thistle is particularly known for its liver-protective properties, artichoke extract has a stronger effect on fat digestion and bile secretion. Both extracts may work synergistically to provide comprehensive support for digestion and liver health [15].
Milk thistle vs. turmeric
Turmeric and milk thistle both have anti-inflammatory and antioxidant properties, but they work in different ways. Turmeric contains curcumin, which reduces inflammation throughout the body, while milk thistle primarily protects the liver and promotes detoxification. Both can be used together to support liver health and overall body detoxification [16].
Final thoughts on milk thistle
Milk thistle is a powerful natural remedy for supporting liver health and detoxification. Whether for treating liver disease, promoting digestion, or strengthening the immune system, milk thistle offers a natural and effective solution. For people seeking to protect or improve their liver function, milk thistle is a valuable dietary supplement that can be taken in capsule, tablet, or lozenge form.