Allergic reactions, abdominal problems, and estrogen and drug interactions are some of the common side effects seen in people who take this herb for extended durations. Learn more about the other negative effects of this herb and what research says about them. Continue reading.
Milk Thistle Side Effects
1. May Cause Abdominal Issues
Research states that milk thistle can cause certain abdominal problems like diarrhea, bloating, gas, and an upset stomach. Oral ingestion of milk thistle has also been linked to abdominal fullness (or abdominal pain), anorexia (a loss of appetite), and changes in bowel habits (1).
2. May Cause Allergic Reactions
Milk thistle can cause allergic reactions in people, especially in individuals who are also allergic to ragweed, marigolds, daisies, and chrysanthemums (2). Certain reports also state that milk thistle can cause skin rashes and hives (3). How this happens is yet to be studied. However, if you develop an allergic reaction after taking milk thistle, stop use and consult your doctor.
3. May Interact With Estrogen
Milk thistle is known to have several estrogen-like properties, and certain sources state that it may aggravate a few health conditions (like endometriosis, where the endometrial tissue appears outside the uterus and causes pain) sensitive to estrogen (4). Milk thistle might also decrease hormone levels in the body (5). Taking it along with estrogen pills might reduce their effectiveness. Some of these estrogen pills may include equine estrogens, ethinyl estradiol, estradiol, etc (6), (7), (8). However, more direct research is warranted in this regard.
4. May Have Interactions During Breastfeeding And Pregnancy
Though milk thistle has been historically used to improve the flow of breast milk, its benefits during breastfeeding and pregnancy are not well studied yet. Hence, stay safe and avoid use.
5. May Interact With Cholesterol Medication
Milk thistle might interact with statin drugs, which are known to lower cholesterol levels (lipid-lowering) (9). Some of these drugs may include Mevacor, Lescol, Zocor, Pravachol, and Baycol. Milk thistle interacts with these drugs as both are broken down by the same liver enzymes.
6. May Lower Blood Sugar Way Too Much
Milk thistle contains a chemical called silymarin, which can decrease blood sugar levels (10). Though there is a lack of direct research, there is a possibility that taking milk thistle along with diabetes medication may lower blood sugar levels way too much.
7. May Interact With Other Drugs
Certain drugs are broken down in the liver, and milk thistle might decrease how quickly this happens (11). Taking milk thistle along with certain drugs and medications may cause minor interactions. Some such drugs may include (12):
Indinavir Elavil Valium Celebrex Voltaren Lescol Cozaar Demadex Coumadin Zyflo
Since milk thistle affects how well the liver breaks down these medications, it can affect how well these medications can work. Some research also states that overall, milk thistle may not pose a great risk for drug interactions in humans (13).
8. May Cause Weakness
Certain individuals might experience weakness with milk thistle. Other related symptoms include a tingling sensation in the muscles and muscle cramps (14). In one case, milk thistle had caused excessive sweating and weakness (14). What is the daily upper limit for milk thistle? Check out the infographic below to learn more about the benefits of milk thistle. Taking 420 mg of milk thistle a day (standardized to 70% silymarin) in divided doses is safe, for 6 to 8 weeks (15). However, consult your doctor for the best advice. Where to buy milk thistle? You can buy milk thistle online in the supplement form. You might also get the herb at your nearest supermarket/pharmacy. How long does it take for milk thistle to start working? It may take one or two weeks for milk thistle to start working. Can you drink alcohol while taking milk thistle? Yes, you can drink alcohol while taking milk thistle. For centuries, this herb has been used in fighting hangovers (9). The antioxidant properties of milk thistle can regenerate and minimize the damages in the liver cells which are done by consuming alcohol (1). Can you take milk thistle long term? Yes, you can take milk thistle long term. In animal studies, the antioxidant and radical-scavenging properties of silibinin in milk thistle were found to reduce tumors (16). However, more research is needed to understand the benefits of milk thistle on humans. So, consult a doctor to understand about its long term usage. Does milk thistle cause weight gain? Possibly. Mothers who used milk thistle to boost their milk production reported unwanted weight gain along with irritability and nausea (16).
