Why Most People That Use Charcoal Pills to Pass A Drug Test Fail

Also referred to as activated carbon, there is a lot of hype about the effectiveness of activated charcoal (charcoal pill) in helping marijuana users to pass urine drug tests.

However, there is also a lot of opposition to the effectiveness of charcoal pills in passing THC drug tests.

So, can you rely on a charcoal pill to test negative for THC metabolites? Read on to find out.

What is a charcoal pill

Charcoal pill or activated charcoal is charcoal that is chemically or physically activated. This is done to increase the charcoal’s surface area and also enhance its absorption ability. Activating the charcoal increases its micro-porosity, which increases the surface area to at least 3000 M2.

The high absorption property of a charcoal pill is what makes it famous for passing urine drug tests. When used, a charcoal pill absorbs the THC metabolites in the digestive tract, thus preventing the metabolites from being absorbed into the bloodstream.

Marijuana users ingest charcoal pill through the mouth to the digestive tract. It is later excreted in stool. For this method to work, the THC metabolites should be able to bind with the charcoal in the stomach and excreted through stool, before absorption into the blood.

Some people do not believe that a charcoal pill works to clear the system of THC metabolites. This is because they believe THC is absorbed directly into the blood, and thus the claim on the effectiveness of charcoal pill is false.

However, according to science, once you introduce THC into the system, it goes through a cycle that includes absorption into the bloodstream, then into the intestines, and back to the bloodstream via Enterohepatic Recirculation.

The role of Enterohepatic Circulation to the disposition of THC metabolites 

In enterohepatic circulation, THC metabolites are transported from the liver to the bile and later to the intestines. This is followed by a re-absorption process into the bloodstream before transportation to the liver. This is a continuous and repetitive process.

With time, THC metabolites are excreted through urine as the liver continues to detox the body from the metabolites. Sometimes, THC metabolites are excreted through stool from the intestine before reabsorption into the liver.

How to use a charcoal pill to pass a marijuana drug test 

You will need:

  • Charcoal pill dose
  • Water
  • Urine test strips

You will need to use a charcoal pill at least one week before the test to guarantee good results. You cannot use a charcoal pill as a same-day remedy for drug tests.


You will need to abstain from using marijuana for at least a week when you begin the charcoal pill method. This is yet another reason why most marijuana smokers dislike the charcoal pill method.

  • Take 10g of charcoal pill at least 2 hours before every meal. Ensure you take a lot of water after. You need to have used 30g of charcoal pill at the end of the day. Follow this for two consecutive days.
  • Consume a lot of fiber-rich foods for the next five days and remember to take water.
  • Test for THC metabolites in your urine at regular intervals during this period.
  • Use a charcoal pill on the day of the test to ensure any remaining THC metabolites are trapped.

The digestive process of THC metabolites 

When you eat cannabis rich snacks, at least 95% of the ingested metabolites absorb through the walls of your intestines and stomach into your bloodstream. The metabolites are later transported through the blood into the liver.

Vaping or smoking marijuana introduces THC metabolites directly into your bloodstream through the lungs, lining of the tongue and mouth. Once in the blood, THC metabolites are transported to the liver as part of the body detox protocol. Here, THC metabolites are broken down into 11-hydroxy-THC and further into THC-COOH.

The liver releases glucuronide molecules that breakdown the THC-COOH to THC-COO-glucuronide. This is the form in which THC metabolites are released in urine.

While some of it is excreted through urine, there is a percentage that is sent to the bile. This is proof that THC-COO-glucuronide undergoes the enterohepatic circulation. This was proven by a study that found that high THC-COO-glucuronide samples were present in bile.

How THC-COO-glucuronide gain access to the intestines 

During digestion in the intestines, the process triggers the gallbladder to release bile juice required for the digestion of chyme in the large intestine. Bile from the gallbladder is excreted with waste products like THC metabolites and bilirubin.

It is essential to understand that THC-COO-glucuronide is polar and large. This makes it hard for it to be re-absorbed into the bloodstream through the gastrointestinal walls. Therefore, the bacteria in the gut convert THC-COO-glucuronide back to THC-COOH, which can penetrate the intestine walls and be absorbed back into the bloodstream.

Once in the blood, THC-COOH undergoes enterohepatic recirculation through the liver. The cycle is repeated until the blood is free from THC metabolites. THC metabolites will only leave your bloodstream if:

  • THC-COOH is excreted in stool in the stomach before reabsorption into the blood
  • THC-COO-glucuronide is moved to the kidney and excreted in urine

According to the information above, THC metabolites move from the blood to the digestive system severally. Therefore, if indeed charcoal pill binds with THC-COOH in the stomach, it should be able to remove most, if not all, of the THC metabolites through stool. This way, there is less to no trace of THC in the blood and thus no need for a long detoxification process. In turn, there will be no THC in urine.

Does charcoal pill work? 

According to the most popular research paper on the effectiveness of charcoal pill in passing a marijuana drug test, a charcoal pill can bind with THC metabolites.

According to this research paper, 5mg of charcoal pill can bind to over 1000ng/ml of THC-COOH or THC-COO-glucuronide. In the research, a charcoal pill was replaced with dietary fiber (wheat bran). It was found that the researchers needed to use a lot of dietary fiber to bind the THC metabolites. It required more than 250g of wheat bran to bind to 1000ng of THC.

A clinical study

In this second study, science researchers were interested in determining how effective a charcoal pill is in absorbing THC metabolites during enterohepatic circulation.

For this study, eight healthy individuals were made to ingest THC-COOH in two stages. Later, these subjects were picked at random for treatment using charcoal pill or a placebo. During the second observation, the subjects were treated with different treatment plans.

The charcoal pill was administered at 5mg per dose for six times to make 30g in total. The subjects took 5mg of charcoal pill before taking THC metabolites fifteen minutes later. The subjects then took another 5mg of charcoal pill 5 minutes after taking THC metabolites and 2, 4, 7, and 10 hours later.

According to this research:

  • A day after taking THC, the metabolites were 45% less concentrated in the serum in volunteers who were treated with a charcoal pill.
  • THC metabolites were undetectable 24 hours after completion of a 30g charcoal pill dose
  • The concentration of THC-COO-glucuronide in urine reduced by up to 21% in volunteers who were treated with a charcoal pill.

Based on the studies above, it is clear that a charcoal pill indeed can absorb large amounts of THC metabolites. These are then released from the system through stool. This means that a charcoal pill may be an excellent addition to a regular detox regimen.

Even with the proof that charcoal pill works, according to the numbers from the study, it is clear that the pill only helps to remove most but not all of THC metabolites from your system. Therefore, there is a likelihood that some metabolites may be absorbed into the blood system and to the kidneys. This can lead to a failed urine drug test.

Also, the intake of a charcoal pill can cause constipation and thus calls for the consumption of plenty of water. This can dilute your urine and render it unusable in a drug test. Therefore, a charcoal pill is not a 100% foolproof method for passing a marijuana drug test.

Are there more reliable methods?

If you are looking for a foolproof way of passing a marijuana drug test, the best approach is to use detox kits. These are made to cleanse your system of any THC metabolites immediately or over a longer period.

You can use a test kit such as the Fast Marijuana Detox Kit to get negative results on the presence of THC in the urine. It starts to work immediately you start using it and can thus be used for same-day urine testing.

On the other hand, if you require a long-term solution, a detox kit such as the Premium 7-Day Detox Kit can be the solution. With this detox kit, you can have a THC free system in just seven days.