Published online 2023 Mar 17.

How Can Milk Thistle Help You To Pass A Drug Test

PMID: 3011176 DOI: 10.1s1170072

Avid smokers like myself are constantly looking for new ways to pass THC drug tests. One of the latest rumors I have heard is that milk thistle has cleansing properties. Some people think that it can be used for marijuana detox.

I tried milk thistle extract pills myself to see whether they can actually help flush out cannabis metabolites from my system. Read this article to find out the result.

What Is Milk Thistle

Milk thistle is a natural remedy used to treat a wide range of health conditions. It is an exotic-looking plant with a long stem, spiny leaves, and a bright purple flower at the top. Milk thistle got its name for its green leaves that have many white lines.

However, the looks are not the only interesting things about the plant. The main active ingredient of this herb is that makes it special. It is called silymarin and it an antioxidant with many scientifically proven benefits.

The extract of milk thistle has a very high concentration of the above-said antioxidant (up to 80%). According to scientists, it relieves pain, improves the immune system, and inhibit the development of pathogens.

The plant can be used to treat all kinds of liver and gallbladder disorders. It also promotes skin health and reduces the risk of neurological conditions.

However, can this plant help your body to flush out THC? The short answer is yes, but you should not solely rely on it.

Since milk thistle affects the liver in many ways, it can actually speed up the detoxifying process. In other words, your body will get rid of toxins faster.

How Exactly Milk Thistle Affects THC Levels

Silymarin inhibits the activity of enzymes in the liver responsible for metabolizing drugs. It means that milk thistle increases your cannabis tolerance.

A smoker’s body processes cannabis metabolites in two stages (

  • During the first stage, CYP enzymes add an oxygen molecule to THC, transforming the cannabis metabolites into compounds that are easier to eliminate.
  • The second stage is called the glucuronidation process. UGT enzymes make THC metabolites water soluble to let the body flush them out in the urine.

As I have mentioned above, milk thistle lowers the efficiency of these liver enzymes. As a result, your body processes THC at a slower rate.

Shortly speaking, milk thistle extract potentially reduces the concentration of THC metabolites in a smoker’s urine. In theory, your chances to pass a drug test will be higher.

There are scientific studies that have shown silymarin to decrease the activity of some liver enzymes ( However, I do not want to blindly believe what other people say. That is why I tried milk thistle pills myself to see whether it will affect a drug test results.

Does Milk Thistle Pills Flush Out THC: Product Test

There are many milk thistle pills from different brands. For my test, I picked this product from PURE CO with a high concentration of silymarin ( You can choose any other brand though.

Here is what I did:

Day 1

Usually, I stop smoking at least several days prior to a drug test to make sure I will pass.

So, I quit smoking marijuana and started to take milk thistle capsules according to the instructions.

Additionally, I drank as much waster as my stomach could handle.

Day 2

I refused high-fat foods this day to give my liver a break. It is not only unhealthy but also makes your body store more THC.

In case if you did not know, cannabis metabolites are stored in the fat cells. Stay fit if you want to improve your chances of passing a drug test!

I continued to drink a lot of water this day. As to milk thistle pills, I took them with every meal (three times overall).

Depending on the silymarin concentration in the product you use, you might need to take a different amount of pills. I recommend you to follow the instructions provided with the remedy.

Test Day

On the last day, I woke up early and drank nearly a gallon of water.

I also swallowed a couple of milk thistle capsule several hours before the test.

That is it. The test is finally over! Let us see at the results.

Test Results

I have used five home marijuana tests from different brands.

Unfortunately, 3 of 5 tests were positive.

The most accurate THC strips that I usually use showed that I did not pass the test.

Nevertheless, the concentration of THC metabolites in my body has definitely decreased since some tests were negative.


As you can see, milk thistle reduces the THC concentration in piss indeed. However, this solution is very unreliable.

I have been consuming milk thistle for 3 days. As a result, 2 out of 5 THC strips were negative. However, I doubt that I would pass a professional drug test.

Thus, I recommend you to use milk thistle capsules together with a reliable detox product. Solutions like a Fast Marijuana Detox Kit from GreenFleets will help you to flush out all the THC from your body.