Milk Thistle, Your Everyday Health Hero

Milk thistle is an herb with history. For more than 2,000 years, humans have turned to milk thistle (Silybum marianum) for its healing effects, with its first use dating back to ancient Greece, where it was reportedly used as a liver tonic and as a treatment for snake bites and mushroom poisoning. John Gerard, an English herbalist who lived during the Renaissance, noted that milk thistle was “the best remedy against melancholy diseases.” In other words, depression. Many of us are most familiar with milk thistle for optimizing liver function, and it is particularly effective in supporting liver health, but modern science is proving that milk thistle is more than a one-trick pony. Its anti-inflammatory and antioxidant effects have been studied in a wide-range of health conditions that go far beyond liver health. Let’s take a look at how milk thistle can be your everyday health hero!

Supreme Antioxidant Power

The main bioactive compound in milk thistle responsible for its health benefits is silymarin, a complex of flavonoid compounds that include silybin, silychristin, and isosilycristin, among others (for simplicity, we will just call it silymarin). These compounds—primarily found in the seeds—have significant antioxidant activity, which is where milk thistle really shines. Indeed, it is its antioxidant power that researchers recognize as the key to milk thistle’s health benefits, in everything from liver and metabolic health to brain and joint health.

Specifically, silymarin has been shown to increase levels of superoxide dismutase (SOD) and glutathione peroxidase, powerful enzymes that play a crucial role in protecting cells from oxidative damage by neutralizing reactive oxygen species (ROS). It has also been found to significantly reduce markers of lipid (fat) oxidation in the cells. In simple terms, silymarin enhances whole-body antioxidant defenses and reduces the oxidation of cells. Why is antioxidant protection so important? Free radicals, like ROS, damage cellular membranes, interfering with their proper functioning; an excessive amount of oxidative damage is the underlying cause of a number of chronic diseases and health issues. Antioxidants protect cells from damage, keeping them healthy and functioning as they should.

Love Your Liver with Milk Thistle

The liver is one of the hardest working organs in the human body and is key to many vital functions, including nutrient storage, digestion and metabolism, regulating blood sugar, hormone production, and of course, detoxification. But our livers are struggling—rates of chronic liver disease and deaths from it are rising, especially among young adults; this includes both alcoholic fatty liver disease as well as non-alcoholic fatty liver disease (NAFLD). NAFLD is also the most common liver disease in children, and due to childhood obesity, is a growing problem. There has never been a better time to love your liver, and milk thistle is the perfect place to start.

Chronic liver diseases have an underlying component of oxidative stress and silymarin provides the liver with potent antioxidant protection, directly and indirectly: it neutralizes free radicals directly but it also boosts the body’s own defenses by increasing antioxidant enzymes, like glutathione, in the liver. Silymarin is particularly important for neutralizing the toxic by-products that are formed during detoxification, which, if left to accumulate, can lead to serious inflammation and oxidative damage to the liver. Research has shown that it also improves liver regeneration, reduces inflammation and fat buildup, and inhibits the formation of tough, fibrous tissue (fibrogenesis) that is a hallmark of liver disease.

A 2024 study investigated the effect of silymarin-supplemented cookies on markers of liver and metabolic health in 64 patients with NAFLD. Participants were divided into four groups: placebo and three treatment groups that received a total of either 200mg, 300mg, or 400mg of silymarin daily for three months. Markers of liver damage and inflammation as well as metabolic health were measured at the beginning of the study and after three months. The researchers saw a significant reduction in liver enzymes (elevated levels indicate liver damage or disease) and inflammatory markers in those taking the silymarin. Additionally, the patients taking the silymarin saw an increase in HDL cholesterol and significant decreases in LDL cholesterol and triglyceride levels after three months, indicating improved cardio-metabolic health. The best improvements were observed in the groups taking 300mg or 400mg daily.

And Your Skin Will Benefit Too!

A happy side effect of taking milk thistle to support your liver’s best health is clear, healthy skin. How well (or poorly) the liver is working is often reflected in our skin—when liver function is compromised, it can manifest as skin issues. By supporting liver function and balanced detoxification, silymarin indirectly promotes healthy skin. It can also directly support skin health with its antioxidant and anti-inflammatory potential, particularly against environmental stressors like UV radiation, which increases free radical production and inflammation, leading to accelerated skin aging, reduced elasticity, and hyperpigmentation. In vitro models have shown that silymarin treatment reduces free radical production and inflammation in UV-stressed human skin cells and inhibits collagen and elastin-degrading enzymes and a recent human study found that silymarin is effective in improving acne. The clinical trial, including 60 subjects with acne, looked at the efficacy of oral silymarin compared to a common prescription drug for acne, doxycycline. The participants were divided into three groups: group one supplemented with 140mg of silymarin daily, group two took 100mg of doxycycline daily, and group three took both the silymarin and doxycycline daily, all for eight weeks. While the final results showed that the combination therapy had the greatest benefit, taking silymarin alone was comparable to doxycycline alone in improving acne lesions.

Protect Your Brain with Milk Thistle

The brain is especially vulnerable to oxidative stress and inflammation, which are directly connected to accelerated brain aging, an increased risk of developing neurodegenerative diseases like Parkinson’s and Alzheimer’s, and mood disorders. Because milk thistle is such an effective antioxidant, scientists have begun to investigate its effect on brain health, particularly looking at silymarin’s potential as a neuroprotective agent in various brain disorders, including neurodegenerative and mood disorders. The results are promising.

A 2024 study investigating silymarin’s effect on biomarkers of oxidative stress, inflammation, and disease severity in 33 Alzheimer’s patients found that silymarin, when taken in conjunction with the standard medication, significantly decreased oxidative stress and improved cognitive function. The dose of silymarin was 150mg, three times daily. The researchers concluded, “Silymarin can be effective as an adjunct drug and powerful antioxidant in reducing oxidative stress and improving the course of AD.” In addition to its antioxidant and anti-inflammatory protection, research has also shown that silymarin inhibits the aggregation of amyloid beta proteins, a hallmark of Alzheimer’s disease.

In a 2017 study, researchers found that silymarin restored normal levels of antioxidants, including glutathione, and reduced markers of oxidative stress in the hippocampus and cerebral cortex in a rodent model of depression. It also reduced markers of inflammation in those same brain regions. Research has also shown that silymarin can restore levels of dopamine, serotonin, and norepinephrine in the hippocampus and cerebral cortexes of depressed rodents (these neurotransmitters are typically depleted in cases of depression). And finally, silymarin upregulates the production of brain-derived neurotrophic factor (BDNF), which plays a critical role in neurogenesis (the growth of new neurons) and brain plasticity, or the brain’s ability to grow and change—essential for learning and memory.

And There’s More!

In addition to liver, skin, and brain health, research is discovering that milk thistle is truly a whole-body health hero. Studies investigating silymarin’s effect on metabolic health markers in type-2 diabetics and non-diabetic obesity have found that it significantly improves glycemic control and insulin resistance, while reducing triglyceride and total cholesterol levels. Doses range from 420mg to 600mg daily.

Studies have also found that milk thistle can relieve pain from rheumatoid and osteoarthritis. A 2024 clinical trial including 122 subjects with rheumatoid arthritis tested the efficacy of milk thistle taken as an adjunct therapy with their prescribed antirheumatic drugs. The subjects took either 375mg of milk thistle extract daily (providing 300mg silymarin) or a placebo for eight weeks. After eight weeks, the milk thistle group showed significant improvements in tender and swollen joints, pain, and morning stiffness, while the control group’s symptoms worsened. Fatigue, depression, and anxiety scores also improved among those taking milk thistle. An earlier study found that 300mg of silymarin taken daily for eight weeks significantly reduced inflammatory markers in people with knee osteoarthritis, used alone, or in combination with NSAIDs.

Do you suffer from menopausal hot flashes? Milk thistle may help! A 2020 study including 80 menopausal women experiencing hot flashes found that taking 400mg milk thistle extract daily for 12 weeks led to a significant decrease in the frequency and intensity of hot flashes, as well as an improvement in overall quality of life.

As you can see, milk thistle’s benefits go far beyond liver health. With its potent antioxidant capabilities and its anti-inflammatory effects, this herb truly is an everyday health hero that we all can benefit from!