When is the best time to take milk thistle?

Milk thistle (Silybum marianum) is a tall plant with purple flowers that belongs to the daisy family. Originally native to Europe, milk thistle can now be found all over the world. The plant’s main active ingredient, an antioxidant called silymarin, is responsible for many of the health benefits of milk thistle. Because of this, milk thistle and silymarin are often used interchangeably to refer to the same plant. Milk thistle is sold as a supplement in an oral capsule, tablet, or liquid tincture. Traditionally, milk thistle has been used to support your liver, gallbladder, and kidneys, says William Li, MD, a Harvard-trained healthcare provider. It may also improve insulin sensitivity and reduce blood sugar levels, Dr. Li adds.

The best time to take milk thistle is at mealtimes or about 15 minutes before your meals. The dosage is often split up and taken two to four times per day, so it may make sense to take milk thistle with breakfast, lunch, and dinner.

The best time to take milk thistle

The best time to take milk thistle is about 15 minutes before breakfast, lunch, and dinner. That way, it’s easy to remember when you’re supposed to take it. “It’s generally best to take milk thistle in divided doses, multiple times daily, versus taking it all at once,” says Jenna Volpe, RDN, a functional dietitian and clinical herbalist practicing in Austin, Texas. 

It’s better to take milk thistle with food rather than on an empty stomach, whether you’re taking a capsule, tablet, or liquid form, Dr. Li says. “Taking milk thistle with food can increase the absorption of its bioactives,” he explains.

In some cases, milk thistle may be taken without food. The timing of milk thistle supplements can vary on an individual basis and is best left up to you and your healthcare provider, says Volpe. 

RELATED: How to make sure you absorb your supplements

How much milk thistle should I take daily?

Like many herbal supplements, there isn’t a standard recommendation for how much milk thistle to take. Before starting milk thistle supplementation, it’s always a good idea to consult with a healthcare professional or pharmacist.

“It’s been studied at doses up to 700 mg three times per day for six months without any notable side effects,” Dr. Li says. In one study, adults were given 1,260 milligrams (mg) of milk thistle per day. In other research, patients were given higher doses of 2,100 mg daily. Stay on the safe side by taking the equivalent of 2 grams of milk thistle per day or less.

There is no research that outlines the safety of milk thistle for children, according to Mount Sinai.

What should not be taken with milk thistle?

Milk thistle may interact with some medications. It is broken down by enzymes produced by your liver cells, and its common drug interactions are with medications that are broken down by the same liver enzymes.

According to the Mayo Clinic, some of these possible interactions include:

• Substrates for cytochrome P450 2C9, such as Valium (diazepam) and Jantoven (warfarin)
• Some diabetes medications
• Evista (raloxifene)
• Olysio (simeprevir)
• Rapamune (sirolimus)

Other medications, such as those that treat allergies, high cholesterol, anxiety, and cancer, could also interact with milk thistle, according to Mount Sinai.

Since milk thistle can lower blood sugar levels in people with Type 2 diabetes, some healthcare providers advise against taking it while also taking diabetes medication. It’s also unclear if milk thistle is safe for pregnant and breastfeeding women, despite some claims that it could help increase milk supply. When in doubt, consult with your healthcare provider or pharmacist about whether this supplement is right for you. During your consultation, be sure to provide a comprehensive list of all medications you are currently taking, including herbal supplements and over-the-counter (OTC) medications.

Side effects of milk thistle

Though milk thistle appears to be well-tolerated in the limited research available, there’s a lot that’s still unknown, notes the National Center for Complementary and Integrative Health. More research is needed to establish its safety and effectiveness.

The most common side effects of milk thistle are:

• Nausea
• Diarrhea
• Bloating
• Headaches
• Skin reactions

These are typically mild. Rare but more serious side effects are possible, such as allergic reactions. Because milk thistle belongs to the daisy family, anyone with allergies to ragweed,  chrysanthemums, marigolds, chamomile, yarrow, or daisies should avoid this supplement. Discontinue taking milk thistle at the first sign of an allergic reaction and seek medical attention. In high doses, side effects may be more likely. 

Signs that milk thistle supplements are working

Milk thistle supplements are sold over-the-counter and can vary by manufacturer. Manufacturers may claim that milk supplements improve liver function, skin health, digestion, and overall well-being. However, since herbal supplements are regulated as food and not drugs, many of these claims may be unfounded.

When taking milk thistle or any new supplement, it can take some time before noticing any improvements. “Based on clinical studies, it can take several weeks to several months for any noticeable effects to be evident,” says Dr. Li.

To know if milk thistle is working, monitor the symptoms you’re taking it for. For example, women who use milk thistle as an herbal remedy for breastfeeding may see increased milk supply. People with acne may notice clearer skin. However, some improvements may only be confirmed through lab testing. Milk thistle used to treat liver diseases, such as cirrhosis, hepatitis B, or fatty liver disease, may not yield immediate improvements but could have positive effects on blood markers.

If you’re not sure if milk thistle is right for you or if it’s improving your well-being, check with your healthcare provider.