milk thistle

Action and Spectrum

Actions and Spectrum: 

milk thistle (Silybum marianum) is an herbal plant used for nearly centuries for its potential health benefits. The active compound in milk thistle is known as silymarin, a complex of flavonoids, including silybin, silydianin, and silychristin. Silymarin is believed to be responsible for most medicinal properties associated with milk thistle. 

Action: 

The primary action of milk thistle is as a hepatoprotective agent, meaning it supports and protects the liver. It has been traditionally used to treat liver conditions such as hepatitis, cirrhosis, and fatty liver disease. Silymarin has antioxidant and anti-inflammatory properties, which help to diminish oxidative stress and inflammation in the liver. 

Spectrum: 

The spectrum of milk thistle’s effects extends beyond liver health. It has also been studied for its potential benefits in other areas: 

• Antioxidant and anti-inflammatory effects: Silymarin has been shown to scavenge free radicals and diminish oxidative stress in various tissues throughout the body, which may have protective effects on cells and tissues. 
• Gallbladder support: milk thistle may help improve bile flow from the liver, benefiting individuals with gallstones or gallbladder problems. 
• Anti-cancer properties: Some research suggests that milk thistle extracts, particularly silybin, may have anti-cancer effects by inhibiting the growth of cancer cells and advancing apoptosis (programmed cell death). However, more studies are needed to understand its potential in this area fully. 
• Diabetes management: Preliminary studies indicate that milk thistle may positively impact blood sugar control by improving insulin resistance and reducing blood glucose levels. However, more research is needed to establish its effectiveness. 
• Skin health: Topical application of milk thistle extract has been explored for its potential benefits in treating various skin conditions like acne, psoriasis, and eczema. It’s antioxidant and anti-inflammatory properties may help soothe and heal the skin. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Anorexia 

Dyspepsia 

Abdominal bloating/pain 

Allergic reactions 

Pruritus 

Nausea 

Anaphylaxis 

Flatulence 

Rash 

Diarrhea 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

• Allergy or sensitivity: Individuals allergic to plants in the Asteraceae/Compositae family, such as ragweed, daisies, or marigolds, may also react to milk thistle. It is advisable to exercise caution or avoid milk thistle if you have known allergies or sensitivities to these plants. 
• Hormone-sensitive conditions: milk thistle may have estrogenic effects, which means it could potentially interfere with hormone-sensitive conditions such as breast, uterine, or ovarian cancers, as well as endometriosis or uterine fibroids.  
• Anticoagulant/antiplatelet medications: milk thistle may have mild antiplatelet and anticoagulant effects, meaning it could potentially increase the risk of bleeding when used in combination with medications that have similar effects, such as aspirin, warfarin, or heparin. If you are taking these medications, discussing the use of milk thistle with your healthcare provider to ensure no adverse interactions is essential. 
• Certain medications: milk thistle may interact with various medications, including but not limited to antipsychotics, antiviral medications, chemotherapy drugs, immunosuppressants, statins, and certain antifungal medications.  
• Pregnancy and breast-feeding: There is limited research on the safety of milk thistle during pregnancy and breastfeeding. It is generally recommended to avoid using milk thistle during these periods to err on the side of caution. It is always advisable to consult with a healthcare professional before using any herbal supplements during pregnancy or while breastfeeding. 

Caution 

• Dosage and quality: Using excessively high milk thistle or low-quality supplements may increase the risk of side effects or reduce effectiveness. 
• Gastrointestinal issues: Sometimes, milk thistle may cause mild gastrointestinal disturbances such as diarrhea, stomach upset, or bloating. If you experience any persistent or severe gastrointestinal symptoms, it is advisable to discontinue use and consult a healthcare professional. 
• Interactions with medications: milk thistle can interact with certain medications, potentially affecting their efficacy or increasing the risk of side effects. 
• Surgery: milk thistle may have mild anticoagulant effects, which could increase the risk of bleeding during surgery. It is generally recommended to discontinue milk thistle use at least two weeks before a scheduled surgery or invasive procedure. Consult your healthcare provider for specific guidance based on your situation. 
• Monitoring liver function: While milk thistle is commonly used to support liver health, it should not replace regular medical monitoring or treatment for liver conditions. Suppose you have an existing liver condition or are undergoing treatment. In that case, working closely with your healthcare provider to monitor your liver function and adjust your treatment plan as needed is essential. 
• Children and infants: The safety and efficacy of milk thistle in children and infants have not been extensively studied. Therefore, consulting with a pediatric healthcare professional before administering milk thistle to children is advisable. 

Pregnancy / Lactation

Pregnancy consideration:  

US FDA pregnancy category: Not assigned. 

Lactation:   

Excreted into human milk: Not known. 

Pregnancy category: 

• Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 
• Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 
• Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    
• Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    
• Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    
• Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

The pharmacology of milk thistle (Silybum marianum) primarily revolves around its active compound, silymarin, a complex mixture of flavonolignans, together with silybin, silydianin, and silychristin. Silymarin exhibits hepatoprotective effects by acting as an antioxidant, scavenging free radicals, reducing oxidative stress, and inhibiting lipid peroxidation.

It also has anti-inflammatory properties, modulates immune responses, and promotes liver cell regeneration. Silymarin may enhance liver detoxification processes, inhibit fibrosis, and reduce the production of pro-inflammatory cytokines. It interacts with various cellular signaling pathways, including apoptosis, cell cycle regulation, and angiogenesis. In preclinical studies, milk thistle has been shown to possess antidiabetic, anticancer, and anti-inflammatory effects. 

Pharmacodynamics: 

Mechanism of action: The mechanism of action of milk thistle (Silybum marianum) is multifaceted and needs to be fully understood. The primary active component of milk thistle, silymarin, which is a complex mixture of flavonolignans, including silybin, silydianin, and silychristin.  

• Antioxidant activity: Silymarin exerts potent antioxidant effects by scavenging free radicals and reducing oxidative stress. It helps protect cells and tissues from damage caused by reactive oxygen species (ROS) and inhibits lipid peroxidation. The antioxidant activity of silymarin contributes to its hepatoprotective properties. 
• Anti-inflammatory effects: milk thistle exhibits anti-inflammatory properties by inhibiting the production of pro-inflammatory cytokines and modulating inflammatory pathways. It helps reduce the release of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-α) and interleukins, contributing to tissue damage and inflammation. 
• Liver protection and regeneration: milk thistle is well-known for its hepatoprotective effects. It helps stabilize liver cell membranes, preventing the entry of toxins into liver cells. Silymarin also stimulates protein synthesis and enhances the production of new liver cells, supporting liver regeneration. It can modulate various signaling pathways involved in liver cell growth, differentiation, and apoptosis. 
• Detoxification support: milk thistle supports liver detoxification processes by promoting the activity of phase II detoxification enzymes, such as glutathione S-transferase (GST). These enzymes are crucial in eliminating toxins and xenobiotics from the body. Silymarin also helps prevent the depletion of glutathione, a potent antioxidant and a key component of detoxification processes. 
• Anti-fibrotic effects: milk thistle may help inhibit the development and progression of liver fibrosis. It interferes with the activation of hepatic stellate cells, which deposit extracellular matrix proteins that lead to fibrosis. Silymarin may also reduce transforming growth factor-beta (TGF-β) production, a key mediator of fibrosis. 
• Anticancer potential: In preclinical studies, Silymarin and its components have demonstrated anticancer effects. They can inhibit cell proliferation, induce apoptosis (programmed cell death), and modulate various signaling pathways in cancer development and progression. However, more research is needed to understand the full extent of milk thistle’s anticancer properties. 

Pharmacokinetics: 

Absorption 

Silymarin, the main active component of milk thistle, is poorly water-soluble. However, it is thought to be absorbed in the small intestine through passive diffusion. Fatty acids or lecithin in the digestive system can enhance its absorption. 

Distribution 

After absorption, silymarin is distributed throughout the body. It has been detected in various tissues, including the liver, kidneys, lungs, and gastrointestinal tract. Silymarin is also known to cross the blood-brain barrier to some extent. 

Metabolism 

The metabolism of silymarin occurs primarily in the liver. It undergoes extensive hepatic metabolism, mainly through phase II conjugation reactions such as glucuronidation and sulfation. The significant metabolites include silybin glucuronides and sulfates. Some minor metabolites have also been identified. 

Elimination and Excretion 

The excretion of silymarin and its metabolites occurs mainly via the bile into the feces. Renal excretion is relatively low, with a small percentage of the compounds being eliminated in urine. The enterohepatic circulation of silymarin and its metabolites contributes to its prolonged presence in the body. 

Adminstartion

Administration: 

Oral administration 

milk thistle (Silybum marianum) can be administered in various forms, including capsules, tablets, liquid extracts, and as a component of herbal tea blends. The administration method and dosage may depend on the specific product and the condition being addressed.  

• Capsules or tablets: milk thistle supplements are widely available in capsule or tablet form. Follow the recommended dosage instructions provided on the product label. However, dosages may vary, so referring to specific product instructions is essential. 
• Liquid extract/tincture: milk thistle extract is available in liquid form, usually referred to as a tincture or liquid extract.  
• Herbal tea: milk thistle can be incorporated into herbal tea blends. Commercially prepared milk thistle tea bags or loose dried milk thistle leaves can be steeped in hot water for 5-10 minutes. However, it’s important to note that the concentration of active compounds in tea preparations may be lower compared to standardized extracts. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: milk thistle 

Why do we use milk thistle? 

Due to its potential therapeutic properties, milk thistle (Silybum marianum) has been used for various health purposes.  

• Liver support and detoxification: milk thistle is widely recognized for its hepatoprotective properties, meaning it supports liver health and also protects the liver from damage. It is commonly used to support liver function in conditions such as hepatitis, cirrhosis, fatty liver disease, and toxin exposure. milk thistle may help promote liver cell regeneration, reduce inflammation, and protect against oxidative stress. 
• Liver conditions: milk thistle is often used as a complementary treatment for liver conditions, including viral hepatitis (such as hepatitis B and C), alcoholic liver disease, and liver damage caused by toxins or medications. It may help improve liver enzyme levels, reduce liver inflammation, and support overall liver health. 
• Gallbladder support: milk thistle has been used traditionally to support gallbladder function and promote the healthy flow of bile, which typically aids in digestion and fat metabolism. It may be beneficial for individuals with gallstones or gallbladder disorders. 
• Antioxidant and anti-inflammatory effects: milk thistle contains flavonoids and other compounds with potent antioxidant and anti-inflammatory properties. These properties help neutralize harmful free radicals, reduce oxidative stress, and alleviate inflammation. 
• Diabetes management: Preliminary studies suggest that milk thistle may positively impact blood sugar control and insulin resistance in individuals with diabetes or metabolic syndrome. It may help regulate blood glucose levels and improve markers of insulin sensitivity. 
• Skin health: milk thistle has been explored for its potential benefits in various skin conditions, including acne, psoriasis, and eczema. Its antioxidant and anti-inflammatory properties might help reduce skin inflammation, support wound healing, and promote overall skin health. 
• Cancer support: Some research suggests that milk thistle extracts, particularly silybin, may have anti-cancer properties by inhibiting the growth of cancer cells and advancing apoptosis in certain types of cancer. However, further studies are needed to understand its full potential in cancer treatment.