What can mess up a hair follicle test?

Author: Ms. Yasmin Emmerich V  |  Last update: Thursday, May 22, 2025

There are many factors that have the potential to impact the results of a hair drug test, including:
  • Hair treatments, such as bleaching, dyeing, perming and straightening.
  • Hair colour.
  • Hair growth rate and length of hair available.
  • Environmental factors, such as passive exposure to drugs.
  • Attempting to 'cheat' the test.

What can cause a false positive on a hair follicle test?

Prescription medications and certain foods, such as poppy seeds, may contain compounds that might lead to false positive results. Hair samples undergo a two-step process to ensure accurate test results. The first step involves an enzyme-linked immunosorbent assay (ELISA) test, which is a rapid screening method.

What fails a hair follicle test?

Hair testing can only detect drugs that have been consumed; it cannot detect drugs that have been injected or breathed. This is a crucial point to keep in mind.

What shows up on a hair follicle test?

A hair follicle drug test may focus on detecting one specific drug in the hair or on detecting several substances in a hair follicle drug panel. One commonly used hair follicle drug panel looks for evidence of the use of five drugs or drug classes: marijuana, amphetamines, cocaine, PCP, and opioids.

How often are hair drug tests wrong?

In fact, it is estimated that over 15% of all hair drug test interpretations will yield inaccurate results - a worrying figure that could have huge implications for your client. It might sound counterintuitive, but positive doesn't always mean positive, and this is where complications emerge.

Hair Follicle Drug Test—Pros & Cons, Myths, and How It Works

What is the most common false positive drug test?

The most common false positive drug test is for amphetamines, which can be triggered by over-the-counter decongestants, the nasal inhaler Benzedrex, the antidepressant Wellbutrin, and the weight-loss supplement Acutrim (WebMD).

Can a hair follicle test be cheated?

In theory, hair drug tests can be attempted to be cheated or manipulated, but it's not easy to do so effectively. Hair drug testing is considered tamper-resistant, which means that it is difficult to manipulate the results of the test.

Does peroxide remove drugs from hair?

Bleaching hair peroxide decreases the detectability of cocaine in user hair. Melanin–cocaine bonds are broken and cocaine is degraded into reaction products. Unbound cocaine and reaction products are washed out removing evidence of cocaine use.

How sensitive are hair follicle tests?

Hair Test Accuracy Compared To Other Testing Methods

Hair testing provides a longer detection window than other testing techniques like urine or blood tests, but it is not as good at detecting recent drug use (i.e. within the last seven days).

What do employers look for in a hair follicle test?

Hair drug testing can detect a variety of drugs including, but not limited to: marijuana, cocaine, opioids (including codeine, morphine, heroin, and synthetic opioids), methamphetamine, ecstasy (MDMA), and PCP.

Can you mess up a hair follicle test?

Bleaching, dyeing, perming, and straightening can all impact a hair drug test result. This is because the chemicals used in these types of treatments can damage the hair shaft and alter the concentration of the drug.

Can a person beat a hair follicle test?

Can a hair drug test be beaten or adulterated? We have not found any adulterants that can beat a hair drug test at this time. Moreover, the risk is minimized because every hair collection is observed.

How far back does a hair follicle test detect drug use?

What time period does a hair drug test cover? Hair growth rates vary; typically, head hair grows at an average of one-half inch per month. Therefore, a 1.5-inch hair sample detects drug use up to 90 days prior to testing.

How can I pass my hair follicle test?

While abstaining from drug use is the only surefire way to pass a hair drug test, awareness of the test's capabilities and limitations is essential for informed decision-making.

Can a hair follicle test be manipulated?

Intentional hair manipulation to avoid positive drug testing mainly relies on forced washing-out effects (“dilution of the hair”), for example, through extensive washing or even the use of commercially available cleansing shampoos advertised to produce negative hair testing results.

How does sweat affect hair drug tests?

Drugs and metabolites can also get into hair via sweat and other secretions, particularly from the sebaceous glands. When contamination is a possibility, the detection – or non-detection – of metabolites in the hair is useful to differentiate external contamination from ingestion.

What are the odds of passing a hair follicle test?

Specificity of hair testing at standard laboratory cut-offs exceeded 90% for all drugs, but sensitivity of hair testing relative to self-report was low, identifying only 52.3% (127/243) of self-disclosed marijuana users, 65.2% (30/46) of cocaine users, 24.2% (8/33) of amphetamine users, and 2.9% (2/68) of opioid users.

What pops up on a hair follicle test?

Hair drug tests typically test for cocaine, marijuana, opiates, methamphetamine, ecstasy, and PCP.

Will a hair test detect one-time use?

Can Hair Drug Tests Identify One-Time Use? The simple answer is yes. However, the frequency, amount, and timeframe in which the person used drugs can affect the outcome of the hair follicle drug test. Hair tests have a limitation, they can't detect recent drug use until roughly five days after exposure.

Can eyebrows be used for a hair drug test?

Hair drug test collection

If the donor does not have head hair or if their hair is less than a ½ inch long, a specimen can be taken from other locations on the body. In order of preference, our collectors will cut the chest, underarm, leg, or facial hair to obtain a sample.

What shampoo to use to pass a hair follicle test?

Safe and Effective Ingredients

The Old Style Aloe Toxin Rid Shampoo and the Zydot Ultra Clean Shampoo contain penetrating cleansing agents that are gentle on the hair while effectively removing residual buildup, environmental pollutants, chemicals, chlorine, hard water minerals, and hair-dulling impurities.

How do I detox my hair for a drug test?

Some of the methods include shaving all of the hair off, detox shampoos, and home remedies including substances like tar shampoo, laundry detergent, detox salts, and vinegar. Some people even dye their hair after using these remedies to help mask the changes made to their hair.

What can cause a false negative hair follicle test?

However, hair samples can be manipulated by cosmetic treatments, altering drug concentrations which eventually leads to false negative hair test results.

Can you dye your hair to pass a hair follicle test?

Hair drug testing on dyed or bleached hair may still be worthwhile. Any chemical treatment such as hair dye, bleach, chemical straightening and permanent waves can damage the hair. This damage may lead to some of the drugs that may be present, being leached out from the hair.

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