Is Milk Thistle Your Next Go-To Supplement? 

Milk thistle research is limited, but shows promise for liver health, diabetes and more
milk thistle

People are always looking for the “it” thing that promises to do wonders for their health. We package, bottle and buy all kinds of herbs and remedies that promise to do be the magic bullet for whatever ails us. 

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Sometimes, those things are backed by science. Sometimes not. And sometimes, like with the herbal remedy milk thistle, there’s a bit of science to it, but not enough to know if it’s really doing what it claims. 

“Milk thistle is interesting because from what we know, it might be beneficial for people with various health problems,” states registered dietitian Beth Czerwony, RD, LD. “The problem is that it hasn’t been very well studied in people yet. So, it’s hard to recommend as a safe or effective remedy.” 

What are people using milk thistle for? And what does the existing research say about it? Czerwony explains. 

What is milk thistle? 

Milk thistle is a spiky purple flowering plant in the same family as the daisies and ragweed. It’s sold as an herbal supplement, either as a capsule or a tea.  

Manufacturers claim it encourages healthy liver function, promotes healthier skin, aids digestive health, boosts your immune system and more. But because it’s an herbal remedy, the U.S. Food and Drug Administration (FDA) doesn’t regulate it. So, the makers can claim just about anything without needing legitimate research to back it up. 

Potential benefits of milk thistle  

Milk thistle has been used in herbal medicine for centuries for a variety of conditions. But scientific research on milk thistle is limited. Studies on it haven’t been well verified and some have used some questionable methods or very small sample sizes. And few have tested the effects of milk thistle in people, instead showing results in animal models or test tubes.  

But, Czerwony says, what we do know has pointed to milk thistle as having good potential to have some positive effects across your body. 

“Milk thistle does show strong antioxidant and anti-inflammatory properties, which is also true of a lot of plants and plant-based foods,” Czerwony says. “Based on the research available, milk thistle does show some promise. And no studies have suggested it would be toxic or have harmful effects, so the risks seem rather low.” 

But, again, that’s all based on what we know so far. Further research in people is needed to understand whether overdoing it could cause any harm. Or if milk thistle shouldn’t be used by certain people. Or if there are drug interactions that should be avoided. And so on. So, always talk with a healthcare provider before starting a new supplement or herbal remedy. 

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Czerwony explains what research has taught so far us about milk thistle’s potential benefits:

1. Liver health 

Milk thistle is best known as a supplement for people who are experiencing liver conditions like cirrhosis, hepatitis B and fatty liver disease

Researchers say milk thistle is “the most well-researched plant in the treatment of liver disease.” It’s thought to improve liver function by fighting free radicals, preventing scarring and keeping toxins from attaching to the liver.  

“In my time working with people who are awaiting a liver transplant, milk thistle was a popular remedy some of them would use, in hopes it would help their compromised liver to detoxify,” Czerwony shares. Important to note, most people choose milk thistle as a personal decision for their health, not as a doctor-recommended therapy for liver disease. 

2. Diabetes management 

Some studies suggest milk thistle may help lower blood sugar in people with Type 2 diabetes, without some of the negative side effects — like weight gain and liver complications — that can be associated with some diabetes medications. But researchers were quick to point out that studies thus far aren’t of high quality and more research is needed. 

Czerwony advises people with diabetes or prediabetes to be careful about testing their blood sugar if they’re using milk thistle. Too-low blood sugar (hypoglycemia) can be dangerous, even life-threating for people with diabetes if not treated.  

3. Neurological disease 

Some studies suggest milk thistle could help prevent decline in brain function as you age. That may mean it could provide some level of protection against conditions like Alzheimer’s disease and Parkinson’s disease

“Anytime we’re talking about anti-inflammatory and antioxidant-rich herbs and foods, we expect to see benefits for neuro-protective effects,” Czerwony says. “What research hasn’t shown is whether milk thistle is any more beneficial against cognitive decline than other antioxidant-rich food sources, like fruits, vegetables and foods high in omega-3 fatty acids.”  

4. Bone health 

Studies in animal models suggest milk thistle may help strengthen bones and protect against bone loss and osteoporosis. But understanding whether those results translate into people may be hard to know.

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“A lot of times when people are trying to be proactive with their health, especially after a diagnosis like osteoporosis, they tend to make other changes to live healthier overall, in addition to trying new supplements,” Czerwony explains. “They may become more active or consume more calcium-dense foods. So, it can be hard to separate out what effect each of those changes has.” 

5. Chemotherapy aid  

Some studies show that milk thistle may be beneficial for people who are undergoing chemotherapy treatment for cancer. Researchers say milk thistle may be associated with better chemotherapy results and reduced side effects from chemo. 

That could be because of milk thistle’s antioxidant properties. But more studies would be needed to confirm the effects and understand whether milk thistle is any more or less beneficial for certain kinds of cancers or chemotherapy medications.

6. Acne control 

Milk thistle’s antioxidant and anti-inflammatory effects have also shown promise for treating acne. In one small study, people who took 210 milligrams (mg) of milk thistle for a day for eight weeks experienced a 53% decrease in acne lesions.  

Can you take milk thistle every day? 

Researchers say milk thistle is well tolerated by most people. And they suggest taking up to 700 mg of milk thistle three times per day for 24 weeks has been shown to be safe.  

Side effects are usually mild and may include symptoms like headaches, nausea and other stomach discomforts. Also, people with allergies to plants like ragweed, daisies, marigolds and chrysanthemums may have an allergic reaction to milk weed. 

Studies haven’t yet shown many negative or dangerous effects. But it’s always best to talk with a healthcare provider before starting any kind of supplement or herbal remedy, especially if you’re pregnant, breastfeeding or have been diagnosed with a chronic condition. 

Alternatives to milk thistle supplements 

Czerwony points out that the biggest benefits from milk thistle appear to be based on its status as an antioxidant. But antioxidants are abundant in natural foods. So, it’s likely that you can get similar effects by eating nutrient-rich foods, rather than relying on milk thistle teas and pills. 

“The planet has given us plenty of antioxidant-rich foods that come with other health benefits, too, like vitamins, fiber and more,” Czerwony reinforces. “Based on what we know, milk thistle supplements aren’t giving you much benefit that you can’t also get from a healthy diet that’s rich in a variety of fruits and vegetables.” 

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