Could Milk Thistle Help With Weight Loss?

There’s no sugar-coating it: losing weight–and keeping it off–is ridiculously challenging. A good amount of research shows that many of us fail to stick to our diets for the long-term. Even among those who'd 'successfully' shed the excess pounds, two-thirds of them gain it all back (and then some!) within a few years (1). In other words: lots of people are trying to lose weight… But most of them are gaining it back. That's awfully demoralizing. Especially if you've been striving toward your personal weight loss goals.

Regardless, you must know of someone who's managed to lose weight and keep it off for years. What gives? Spoiler alert: it could have something to do with milk thistle. More on that in a bit. 

What Factors Influence Weight Loss?

But first things first. While successful, long-term weight loss is primarily driven by the maintenance of a calorie deficit (i.e. you need to eat fewer calories than your body burns), the truth is that there is a never-ending list of factors that also play a part (2, 3, 4). You’re probably already well-familiar with the few culprits–including your choice of foods, stress management, sleep, hormone health, and those pesky genetics.

But there is an aspect you’re likely to have overlooked. And that is supplements, which tend to work by 3 common mechanisms: reducing appetite, reducing the absorption of nutrients (e.g. fat), and increasing fat-burning. With a dizzying array of supplements available on the shelves, though, how do you make your pick? Given the title of this article–and the spoiler alert above–you should already know the answer. Yep. If you had to pick one, go for milk thistle. 

What Is Milk Thistle?

Milk thistle is an herbal remedy obtained from the milk thistle plant, also known as the Silybum marianum (5). This prickly plant has distinctive purple flowers and white veins–and has long been used as a traditional, natural remedy to treat a range of health conditions, including cirrhosis, jaundice, gallbladder disorders, and even hepatitis. The milk thistle's ability to confer these health benefits is believed to stem from its active ingredients, a group of plant compounds (i.e. flavonoids) collectively known as silymarin. Studies show silymarin to have antioxidant, antiviral, and anti-inflammatory properties (6, 7, 8). Milk thistle is typically sold as a powder, liquid extract, oral capsule, or oral tablet.

Is There A Link Between Milk Thistle And Weight Loss?

Yes, There Is. 

Here’s the bit you’re most interested in: does milk thistle help with weight loss? According to a 2016 animal study published in Frontiers in Pharmacology, it would appear so (9)! Researchers fed 6 mice a high-fat diet for 3 months to induce obesity, high cholesterol, fatty liver, and insulin resistance. And after that, the researchers continuously fed the mice with either a high-fat diet alone or mixed with silymarin (the active ingredient found in milk thistle) for another 6 weeks.

The findings? It was found that the mice fed with silymarin lost weight–instead of gaining weight! Thus, suggesting that milk thistle may be beneficial for those looking to lose weight.

But Why?

But of course, this is an animal study. The researchers acknowledged that there still needs to be more research on milk thistle's effects on humans' weight loss to collaborate with their findings. Scientists are also unsure of why milk thistle promotes weight loss. Regardless, it seems to be related to milk thistle's effect on blood sugar levels–at least, according to a 2014 study published in The Review of Diabetic Studies and a 2016 study published in the Journal of Diabetes Research (10, 11). These studies show that milk thistle could lower blood sugar levels.

This begs the question: what does a lowered blood sugar level have to do with weight loss? As it turns out, a lot. That's because chronically elevated blood sugar–also medically known as hyperglycemia–leads to weight gain through promoting insulin resistance (12). When your body becomes resistant to insulin, it tries to cope by producing more insulin. And while your cells become resistant to insulin’s effect on blood sugar uptake (i.e. your blood sugar levels remain elevated), they remain responsive to the hormone’s role in increased fat-storing–meaning that you are now storing excessive amounts of fat, especially in the belly area (13, 14, 15, 16, 17).

To make matters worse, high blood sugar levels and insulin resistance interfere with leptin, a hormone that decreases hunger and helps reduce food intake (18, 19). That means you’re likely to feel hungrier–and eat more as a result. Thus, leading to inevitable weight gain. By now, you should be able to see how milk thistle can help with weight loss. It lowers your blood sugar levels, in turn, preventing the adverse effects that insulin resistance brings about.

Other Health Benefits Of Taking Milk Thistle

Other than potentially accelerating your weight loss efforts… What other health benefits can you expect to reap from supplementing with milk thistle? As it turns out, there are many!

Possibly Neuroprotective

First up, studies suggest that milk thistle could be a promising treatment for neurological conditions like Alzheimer’s and Parkinson’s disease (20). And the reason behind this is primarily due to silymarin's anti-inflammatory and antioxidant properties (21, 22). More specifically, both test-tube and animal studies have shown that silymarin can prevent oxidative damage to brain cells, which–in turn–could prevent mental decline (23, 24). These studies have also highlighted silymarin’s efficacy in reducing the number of amyloid plaques (sticky clusters of amyloid proteins) in the brains of animals with Alzheimer’s disease (25, 26, 27).

Exerts Anticancer Effects

There is also increasing evidence on silymarin's anticancer effects. Several studies show that milk thistle could increase chemotherapy's efficacy against certain cancers and, in some circumstances, even destroy cancer cells (28, 29, 30). Some animal studies also highlight that the herbal remedy could reduce the side effects of cancer treatments (31, 32). But of course, more human studies are still needed.

Protects Your Bones

Osteoporosis is a bone condition that causes your bones to become weak and brittle–so brittle that a fall or even mild stresses (e.g. bending over or coughing) can cause a fracture (33). Breaks are most likely to occur in the hip, spine, or wrist. But other bones can break too, of course. In addition to causing life-long pain, osteoporosis can also cause some individuals to lose height. And when the condition affects the vertebrae (the bones of the spine), it often leads to a stooped or hunched posture. Perhaps most worryingly of all is that 20% to 40% of seniors who break a hip die within one year from complications related to the broken bone itself or the surgery to repair it (34). Bottom line? Osteoporosis is nothing to joke about.

Thankfully, experimental test-tube and animal studies have shown milk thistle to stimulate bone mineralization and potentially be protective against bone loss (35, 36). Thus, researchers are hopeful that the herbal remedy may be a useful therapy for preventing or delaying bone loss (37, 38).

Promotes Breast Milk Production

Interestingly, milk thistle has also been shown to boost breast milk production in lactating mothers; it's thought to do so by promoting prolactin–the milk-producing hormone. According to a 2008 study, mothers taking 429 mg of silymarin for 63 days produced 64% more milk than those taking a placebo (39). 

Decreases Number Of Acne Lesions

Still struggling with the occasional bouts of pesky, painful, and unpleasant acne flare-ups? Well, due to its anti-inflammatory and antioxidant effects, milk thistle may be a useful supplement for you. A 2012 study published in the Journal of Clinical & Experimental Dermatology Research found that individuals who took 210 milligrams of silymarin per day for 8 weeks experienced a 53% decrease in acne lesions (40).

Is Milk Thistle Safe?

Ready to supplement with milk thistle to accelerate your weight loss efforts–and improve your health? Of course, you are. Before that, though, let's address an important question: is milk thistle safe? The answer is yes. Milk thistle is generally considered safe when taken orally (41, 42). Even in studies where high doses were used for extended periods, only about 1% of individuals reported side effects, which are generally mild gut disturbances like diarrhea, nausea, or bloating (43).

Don’t Forget To Fix Any Underlying Issues About Food And Eating

Ultimately, milk thistle can help you achieve your weight loss goals quicker–and provide a few added health benefits along the way. That said, the truth remains that you need to stay in a calorie deficit to lose weight. And so… It may be time for you to get reacquainted with your hunger and fullness cues.

Getting back in touch with how it feels to be hungry will help you feed your body properly–and ensure that you're eating the appropriate number of calories that'll help you drop the pounds. However, if your feelings around food begin to feel psychologically-harmful, consider seeking a professional who can guide you and give you the support you need.