How Far Back Does A Hair Follicle Test Detect Drugs?

How Far Back Does A Hair Follicle Test Detect Drugs?


Hair Follicle Tests can trace the usage of certain illegal drugs for an extended amount of time, say, a maximum of 90 days.

The main reason behind the introduction of the hair follicle drug test is their accuracy and longer detection period, which other drug testing methods will find challenging to trace. 

Learn more about hair follicle drug test and how far they can detect drugs.

Table of Contents:

We use chemicals and some prescribed drugs day in and day out, but what makes it illegal is the amount of intake. There are two ways a person gets addicted to illicit drugs, intentionally or unintentionally.

Considering the unintentional factors, the illegal drugs are used in different forms or combinations. Doctors are very aware of these and prescribe a moderate amount so that the patient does not consume excessively, leading to overdose and addiction.

Some people use these drugs via false prescription or smuggling to get addicted. Drug testers have come up with various drug testing methods to prove them guilty. However, they were not effective and were open to loopholes. This is where the hair follicle test came to the rescue.

What is a Hair Follicle Drug Test?

Hair follicle drug testing is one of the drug testing methods where a hair sample is collected from the head or other body parts to test for prime illicit drugs. The hair sample tests became prominent because of their accuracy and extended detection period.

Be it pre-employment, random, post-accident, follow-up, or during probation, hair drug tests outperformed other drug tests by their accuracy percentage in various fields. 

According to the statistics, the urine and oral fluid tests carried 4.15% and 4.73% positive test result rates, whereas the hair drug tests carried a successful positive detection rate of 10.73%.

Subsequently, the SAMSHA  gave a detailed summary of understanding the significance of hair drug tests and looking forward to explore the suitability of hair drug tests in federal drug testing programs.

Hair drug tests cannot detect all the drugs that are considered illegal. Still, they can detect the presence of major illicit drugs that most institutions prefer during pre-employment, probation, or other causes.

Major Drugs That Hair Drug Test Can Detect

Hair drug tests can easily identify the below-mentioned drugs for up to 90 days after the last consumption.

  1. AMP
  2. COC
  3. MAMP
  4. MDMA
  5. PCP
  6. THC
  7. Alcohol
  8. Opioids

The hair drug tests performed well in identifying the above-mentioned drugs in an effective way and the positive test rates during the period 2003-2007 for non-regulated workplace workers were precise.

You may wonder, “How long does the hair follicle drug test go back?” The maximum limit of the detection period is 90 days, but it differs based on the drug variety and the amount of intake.

Before that, we should know the science of drugs entering the hair strands, making them detectable during the hair drug test. 

How Does The Drug Traces Enter Into Hair?

This is a reasonable question since the hair is considered to be a dead cell. To be clear, keratin is a connective tissue that connects the hair to the root.

As the hair grows, the nutrients and other molecules circulate in the blood enter the hair via keratin. They get stored in the hair for a long time, locked up, and have no exit point. 

While the metabolism can wipe away the drug metabolites from the body, the metabolites in the hair cannot get wiped off, as they are trapped in a dead cell. This makes the hair specimen detectable for long-term drug abuse.

Hair follicle tests also have an expiry date but differ from one drug to another. Let us sneak a peek into the detection periods of hair follicle tests for different drugs.

How Long Does Hair Drug Test Go Back?

It should be noted that not all drugs remain in the hair for a long time (90 days). For instance, alcohol stays in the hair for a maximum of two days, making it difficult to trace the drug metabolites.

There are high chances of tracking if the individual is a regular drug abuser. For an occasional drinker, the drug traces may be visible in a feeble amount in the preliminary test, which could be confirmed on the confirmatory testing.

Hair Drug Test Detection Periods for Different Drugs


Hair Sample Detection Period


Maximum of 2 days. The hair drug test cannot accurately determine the drug presence after two days of intake of alcohol.


About 90 days, varies for different brands


About 90 days


Maximum of 90 days


From 30 to 90 days, varies for different brands

Crystal MAMP

Maximum of 90 days


Maximum of 90 days


Up to 90 days


Up to 90 days

These are some drugs that are stored in the hair follicles and can be easily detected for an extended period.

Now that you are aware of the detection period, have you ever wondered whether a hair follicle test detects one-time drug use? Here is the answer for you!

Can A Hair follicle Test Detect One Time Use?

It depends upon the time of drug usage. If the user takes a drug some days before the test, the hair follicle test might not show drug abuse. 

If you take drugs and the metabolites are less than prescribed cut-off levels, they might not show up in the initial/ preliminary hair drug test (Only if the employer uses a drug testing kit). 

The one-time drug use may show up in a lab-based hair drug test only if the usage is before 40 to 90 days. Lab-based hair drug tests might not detect recent drug abuse.

Can a hair follicle test detect alcohol?

Yes. The ETG hair alcohol test can detect alcohol abuse with the help of a hair sample. This is a lab-based drug test that can detect long-term alcohol abuse precisely. Court-ordered drug tests involving child custody and substance abuse cases might be subject to the EtG hair follicle drug test.

Hair drug testing kits might not detect alcohol, but they can help you effectively detect other common illegal substances. 

Final Words

It is irrevocable that hair follicle drug testing has arrived as enlightenment in the world of drug testing. The presence of drugs in the body is not a crime unless it is in acceptable amounts; the hair drug tests reflect the same.

From the above detection duration chart for different drug substances, you may have known about the hair drug test accuracy, detection time, and efficiency.

If you are free of drugs and your drug test is on the cards, there is nothing to worry about. But if you are an occasional or regular drug abuser, it is time to learn how to pass a hair follicle drug test legitimately.

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