Milk Thistle

Milk thistle (Silybum marianum) is a spiky plant with purple flowers and distinctive white-veined leaves, from which it takes its name. It belongs to the daisy family (Asteraceae) and grows across the Mediterranean, though it is now cultivated worldwide. The part used is the seed, which contains silymarin, a group of antioxidant flavonolignans (NCCIH, n.d.)(Ahmed & Sharma, 2024).

In Western herbal practice, milk thistle has been used for centuries to support the liver and gallbladder and to aid digestion. It is important to note that milk thistle is not one of the herbs described in the classical Ayurvedic texts, such as the Charaka Samhita or Sushruta Samhita. Its use is based on modern research and Western herbal tradition rather than classical Ayurveda. It may help support the liver, but it is not a cure for liver disease, and serious liver conditions need proper medical care.

Milk thistle is known by the following common and botanical names:

• Botanical name: Silybum marianum (synonym Carduus marianus)
• English names: Milk thistle, Mary thistle, St Mary’s thistle, holy thistle, blessed milk thistle

Milk thistle is a fascinating plant that supports liver health and contains several vitamins. There are many milk thistle benefits that humankind has known. Here’s a quick overview of the actives found in milk thistle:

1. Silybin (Silibinin):

• Protects liver cells from toxins.
• Promotes liver tissue regeneration.
• It acts as a potent antioxidant.
• Reduces inflammation in liver conditions.
• It may protect skin from UV damage and reduce ageing signs.

2. Isosilybin:

• Supports liver detoxification and regeneration.
• It may inhibit the growth of prostate cancer cells.
• It acts as an antioxidant, protecting against oxidative damage.

3. Silychristin:

• Protects liver cells from toxins.
• Promotes liver cell regeneration.
• It acts as an antioxidant, reducing oxidative stress.
• It may have antiviral properties.

4. Isosilychristin:

• Supports liver protection and detoxification.
• Enhances antioxidant defence in liver cells.
• It may help reduce inflammation.

5. Silydianin:

• Enhances liver detoxification.
• Reduces oxidative stress on liver cells.
• Assists in liver cell repair and regeneration.

6. Taxifolin:

• It acts as a powerful antioxidant.
• Supports cardiovascular health by improving cholesterol levels.
• Reduces inflammation in tissues.
• Protects liver function in combination with other compounds.

These active constituents contribute to overall health, making milk thistle more than just a liver tonic. It’s a plant that supports various functions in our bodies!

Milk thistle is best known for supporting the liver. Its main benefits, framed honestly, are:

May Support Liver Health

Silymarin acts as an antioxidant and helps stabilise liver cell membranes, which is the basis for milk thistle’s traditional use as a liver-support herb. It is studied as a supportive option in conditions such as fatty liver, but it should not replace medical treatment, and serious liver disease needs a doctor’s care.

Antioxidant Effects

Silymarin helps raise levels of the body’s own antioxidant glutathione and counters free radicals, which supports overall cell health. This antioxidant action underlies most of its other proposed benefits.

Digestive Support

Milk thistle may support normal bile production and flow, which plays a role in fat digestion. However, evidence for its effectiveness in relieving bloating or discomfort after fatty meals is limited.

May Support Blood Sugar

Some studies have looked at silymarin for blood-sugar support, possibly through its antioxidant effects. This is an area of research, not a treatment for diabetes. Anyone with diabetes should speak to their doctor before use, as it may affect medication doses.

Skin Health

As an antioxidant, milk thistle may help protect skin cells from oxidative stress and everyday environmental damage. Any skin benefit is general and supportive, not a treatment for a skin condition.

Cholesterol Management 

Some early studies suggest that milk thistle may help support healthy cholesterol levels, but the evidence remains inconclusive. It is not recommended as a primary treatment for managing cholesterol.

Support Metabolism

There is no strong clinical evidence that milk thistle directly promotes weight loss or increases metabolism. While its effects on liver health have been studied, it should not be considered a weight-loss supplement or a substitute for a balanced diet and regular physical activity.

In everyday use, milk thistle is taken in a few main ways:

• As a daily liver-support supplement, usually in capsule or tablet form.
• By people who want digestive support, particularly after heavy or fatty meals.
• Alongside other liver-supporting herbs in combination supplements, under guidance.

Milk thistle is generally well tolerated, but take these precautions:

Allergy to the daisy family

Milk thistle is in the same family as ragweed, marigold and daisies. If you are allergic to these, it may cause a rash, itching or, rarely, breathing difficulty. Ask a doctor before taking it.

Medicines

Milk thistle may affect how the liver processes certain medicines. Consult your doctor before use if you are taking medicines such as blood thinners (for example, warfarin), diabetes medicines or statins.

Pregnancy and breastfeeding

Milk thistle is not generally recommended during pregnancy or breastfeeding due to limited safety data. Consult your doctor before use.

Existing liver disease

If you have a liver condition, do not use milk thistle without medical advice. It should not be used as a substitute for appropriate medical treatment.

Before surgery

Stop taking milk thistle at least two weeks before any planned surgery, as it may affect blood sugar and bleeding.

Do not exceed the dose

Higher doses can cause stomach upset or diarrhoea. Follow the label or your doctor’s advice.

Milk thistle is available in several forms. Follow the product label or your healthcare practitioner's advice for the correct dose. It is generally taken with or after food.

• Capsules or tablets: Swallow with water according to the recommended dose on the label.
• Powder: Mix with water, juice or a smoothie. Follow the product instructions, as strengths may vary.
• Liquid extract: Take the recommended number of drops or measured dose as directed on the product label.

Look for a product that states its silymarin content, as this is the active part, and check with a pharmacist or doctor if you take other medicines.

What matters is the amount of silymarin, the active part, not the weight of raw powder. As a general guide for adults:

• Standardised extract: A common range is 200 to 420 mg of standardised silymarin a day, split into two or three doses, taken with food (NTP/NIEHS, 2011).
• Capsules and tablets: Follow the strength printed on the product, as capsules and tablets vary.
• Children and teenagers: Not recommended, as it is not established for them; only under specialist advice.

Disclaimer: These are general guides, not a prescription. Dose depends on the product and your health. Speak to a doctor or pharmacist before starting, especially if you take other medicines or have a liver condition (NCCIH, n.d.).

Side effects are usually mild. They can include:

• Digestive effects: Mild stomach upset, bloating, gas or loose stools are the most commonly reported side effects, particularly at higher doses.
• Allergic reactions: Milk thistle may cause rash, itching or swelling, especially in people who are allergic to plants in the Asteraceae family, such as ragweed, marigold or daisies.
• Hormone-sensitive conditions: Milk thistle has shown weak hormone-like activity in laboratory studies. People with hormone-sensitive conditions should consult their doctor before use.
• Headache: Headaches have been reported in some people, although they are uncommon.
• Blood sugar: Milk thistle may lower blood sugar levels. People with diabetes should monitor their blood sugar and seek medical advice before use.

Milk thistle may affect how the liver processes certain medicines. Evidence is mixed, so the safe approach is to tell your doctor or pharmacist you take it. Take particular care with:

• Blood thinners: Milk thistle may affect how these medicines work. If you take blood thinners, your doctor may recommend closer monitoring.
• Diabetes medicines: Milk thistle may enhance the blood sugar-lowering effects of these medicines. Blood sugar levels should be monitored, and your doctor may adjust your treatment if needed.
• Statins and other liver-metabolised medicines: Milk thistle may influence how the liver processes certain medicines. Consult your doctor before using them together.
• Some chemotherapy and antiviral medicines: Milk thistle may interact with medicines processed by the same liver enzymes. Seek specialist medical advice before use.

Storage of Milk Thistle

Store milk thistle capsules, tablets or powder in a cool, dry place, out of direct sunlight, with the container tightly closed. Keep liquid extracts as directed on the label, and keep all supplements out of the reach of children.

• Milk thistle (Silybum marianum) is a Western herb whose seeds contain silymarin, an antioxidant compound used to support the liver.
• It is not a classical Ayurvedic herb, and it is a supplement, not a treatment for liver disease.
• It may support the liver, digestion and antioxidant activity; evidence for cholesterol and weight loss is weak.
• A common dose is 200 to 420 mg of standardised silymarin a day, in divided doses, with food.
• Avoid it if allergic to the daisy/ragweed family, and check with a doctor if pregnant, diabetic, on blood thinners or before surgery.
• Serious liver problems need a doctor; do not rely on milk thistle alone.