What Is Milk Thistle Good For, and Can You Take It Every Day?

Substances in milk thistle have anti-inflammatory and antioxidant properties that can help the liver generate new cells and protect itself. Milk thistle is good for liver disease, indigestion, acne, brain health, and breast milk production and it is safe enough to take daily.

For over 2000 years, milk thistle has been used as an herbal treatment for many kidney, liver, and gallbladder illnesses. Research indicates that a flavonoid within milk thistle blocks certain toxins from the liver. The substances in milk thistle have anti-inflammatory and antioxidant properties that can help the liver generate new cells and protect itself. Human studies have mixed results, but there are some uses for milk thistle.

Native to the Mediterranean region, milk thistle is a member of the same plant family as daisies and flowers called Asteraceae. It is found worldwide and grows in sunny, dry areas. The branching spiny stems on the top can reach 5-10 feet high. The name milk thistle comes from the sap in the leaves, which is white-colored. The leaves are wide with white veins or blotches. Flowers are reddish-purple, and the fruit is small, brown, shiny, spotted, and hard-skinned. The seeds spread quickly and can mature in under a year. Early colonists brought the milk thistle plant to North America because it seemed to help with blood sugar lowering. It is now found all over California, the eastern United States, Africa, South America, Asia, and Australia.

Most milk thistle products are prepared from the plant's seed and contain up to 80% silymarin. Silymarin is the active chemical taken from the seeds and is thought to protect the liver. It comes from a group of flavonoids that may help liver cells repair themselves from damage from toxic compounds like alcohol. It is a strong antioxidant and decreases inflammation. 

Milk thistle comes in a few available forms. There are capsules of dried herbs that contain 120–140 milligrams of silymarin. It can be a tincture, a liquid extract, and a silymarin phosphatidylcholine complex. Some literature states the silymarin-phosphatidylcholine complex could be more easily absorbed than regular milk thistle. It contains a key element found in the membrane of human cell walls and helps silymarin attach to the wall, which could keep toxins out of the liver cell. 

The following are conditions that milk thistle is said to affect:

Liver disease from alcohol: It has been suggested that milk thistle may help treat cirrhosis and hepatitis from alcohol damage. Milk thistle supposedly improves liver function and survival in people with hepatitis and cirrhosis. But studies have shown mixed results, and the small number of participants and inadequate dosing in studies have made it difficult to draw conclusions. 

Diabetes: In people with type 2 diabetes, milk thistle may lower blood sugar. This needs more studies to confirm. 

Mushroom poisoning: In traditional medicine, milk thistle has been an antidote for poisoning from death cap mushrooms. Milk thistle extract has been shown to counteract the mushroom's toxic effects if taken within 10 minutes of consumption. This needs more studies to confirm. In animal studies, it greatly reduced liver damage risk if given within 24 hours. 

Bone protection: Over the years, many things can affect the strength of your bones. Osteoporosis develops slowly and makes it easy for fragile, weak bones to break with minor falls. In experiments with test tubes, milk thistle has stimulated the mineralization of bone and protects against bone loss. Many scientists think milk thistle could be useful in therapy for postmenopausal women to delay and prevent bone loss. There are no human studies. 

Indigestion: Along with other substances, symptoms of indigestion have improved with milk thistle. This claim needs more research. 

Acne: Acne is an inflammatory condition of the skin. It is usually pain-free, but it could cause scarring. But some could find it painful and think it impacts their appearance. Because milk thistle has anti-inflammatory and antioxidant properties, it could be a good treatment for people with acne. Though more strong research is needed, one report showed that people who took silymarin at 210 milligrams daily decreased their acne lesions by 53% in eight weeks.

Cancer: Preliminary laboratory studies have hinted that silymarin and other milk thistle ingredients could have anti-cancer effects. Together these properties shorten cancer cell life spans, stop cancer cell reproduction, and decrease blood supply to tumors. 

Age-related brain decline: For over 2000 years, neurological conditions were treated with milk thistle. Its antioxidant properties, along with its anti-inflammatory properties, could make it a neuroprotectant that prevents age-related brain function decline. In test tube studies, oxidative damage to brain cells has been prevented with silymarin, which may decrease mental decline. The same properties may also reduce amyloid plaque numbers in Alzheimer's-diseased brains of animals.

Breast milk production: Some studies have shown that milk thistle can help boost milk production in breastfeeding moms. It affects the lactating hormone prolactin and makes it work harder. There is not a lot of information on it, but one study showed that 64% more milk was produced by lactating moms who took 430 milligrams of silymarin for 63 days. Additional research is needed to certify these results and determine milk thistle safety for lactating moms. 

Unfortunately, clinical trial results of milk thistle on liver disease have been mixed or unclear, and some trials are poorly carried out. However, a few studies have shown good results in those with chronic hepatitis C.

A few studies have shown that milk thistle extract possibly aids the health of those with diabetes. Still, there are no definitive results on its effectiveness. Some research suggests silymarin could supplement sun protection and decrease skin cancer risk. Still, others concluded that milk thistle interacts with chemotherapy. More research must be done to show effects in the body vs. just test tubes. There is no other research on other conditions with definitive results.

If the dose is correct, taking milk thistle orally is supposed to be safe. It can be taken up to three times daily in the appropriate amount. If not taken carefully, milk thistle could possibly cause:

• Itchiness
• Headache
• GI issues like constipation, abdominal bloating, nausea, vomiting, and diarrhea 

The Agency for Healthcare Research and Quality looked at milk thistle effects on the liver and cirrhosis. They found that negative reactions are almost nonexistent. The most common complaints were GI-related but not significantly more than those of the regular population. Allergic reactions were rare. 

For people with diabetes, milk thistle should be taken with caution. It could possibly lower your blood sugar. Some are concerned that it could affect estrogen levels, which could cause problems with uterine cancer, endometriosis, fibroids, ovarian cancer, and breast cancer. As with most herbs, milk thistle can cause a common allergic reaction, even anaphylaxis, in people allergic to other weeds like daisies, marigolds, and ragweed.

There are certain medications that milk thistle can interact with:

Medications for diabetes: In people with type 2 diabetes, milk thistle may lower blood sugar. If you choose to take milk thistle and take medication for diabetes, closely watch your blood sugar levels and discuss it with your medical provider. 

Substrates of cytochrome P450 2C9: Milk thistle may interfere with how your body processes these drugs. The liver breaks down these medications, and milk thistle may affect the levels of medicine in your body.

Morphine: Levels of morphine in the blood could be affected by milk thistle. It could decrease or increase this drug's therapeutic effects and side effects. 

Simeprevir: Avoid taking milk thistle if on this drug. Milk thistle could possibly increase drug levels in your blood plasma. 

Evista: If you have osteoporosis and take this medication, talk to your doctor if you are considering milk thistle as a supplement. It may affect how the liver processes Evista and increase the levels in your bloodstream.

Medications that lower cholesterol: Statin drug interactions with milk thistle are labeled as minor, but be careful with this combo. Milk thistle could affect the medication's levels in the body.

Milk thistle, as a cytoprotectant, has been in use for the treatment of cancer, liver disease, and GI symptoms. Amanita phalloides poisoning is also treated with milk thistle as an antidote. Though we are seeing some results, clinical studies contradict each other, and results are mixed. Besides small GI and allergic responses, side effects are almost unheard of, with major toxicity almost never reported. Orally, 70%–80% silymarin in milk thistle is safe to use for up to 41 months. Current clinical studies in infectious disease and oncology are working to verify the usefulness and success of milk thistle use. As with any new supplement, always consult your doctor before starting a new regimen.