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Hair Testing for Drugs & Alcohol

We work with one of the UK’s leading testing laboratories to provide hair sample analysis

Hair testing for drugs and alcohol is used by individuals, workplaces, social care agencies, family and criminal law, education and government sectors.

How does hair testing work?

When ingested into the body, alcohol and drugs produce specific chemical markers in the body called metabolites. These markers are passed into the hair, which then acts as a record of a person’s alcohol or drug use over time. The presence of these metabolites helps to prove that the compound was ingested by that person.

Hair grows at approx. 1cm per month, so when tested in a laboratory each 1cm of hair sample represents 1 month of metabolites. This is why hair testing is able to provide such a large window of detection; assessing drug use as far back as 6 months and alcohol as much as 2 years.

The time frame of detection required dictates the amount of hair required for the sample. For example, if you need to assess drug use in the past 4 months, then 4 cm of hair will need to be analysed with the laboratory.

As hair takes around 7 days to grow out of the scalp, this is the minimum time frame a hair test can detect. It may therefore be necessary to use hair testing in conjunction with other methods, like oral fluid (saliva) testing.

Advantages of hair testing:

  • Very difficult to cheat
  • Indicates history of alcohol or drug use over weeks and months
  • Highly accurate and reliable
  • Simple collection process

Disadvantages of hair testing:

  • Hair tests cannot precisely determine the quantity of substances used by the donor
  • Samples cannot indicate substance use less than 7 days after the incident
  • If analysis is required for legal/court use, kit cannot be sent direct to Donor

How does hair testing for alcohol work?

The metabolites associated with alcohol consumption are ethyl glucorinide (EtG), fatty acid ethyl esters (FAEEs), and phosphatidylethanol (PEth). These biomarkers are recognised as direct and specific markers of ethanol.


Ethyl Glucorinide (EtG) is produced through non-oxidative metabolism in the liver and through a reaction that is catalysed by isoenzymes. EtG appears in blood less than 45 minutes after alcohol consumption, and in urine in less than 60 minutes. EtG also accumulates in the hair and this allows for a larger window of time for alcohol consumption detection, enabling EtG to be used as a long-term alcohol marker.

EtG testing is the most reliable hair test when determining the levels of alcohol consumed. The EtG test is designed to show a change in pattern of alcohol consumption. From the time that an individual stops drinking, the levels of EtG in the hair decreases in a linear pattern over 3-6 months. However, there are a number of studies that show chemical treatments and bleaching reduce the levels of EtG from the hair, therefore the results should be interpreted carefully.


Fatty Acid Ethyl Esters (FAEE) hair testing is designed to show a long-term (10 months to 2 years) alcohol consumption habit. It is important to note that from the time an individual stops the consumption of alcohol, the levels of FAEE can rise, before dropping 6-9 months after abstinence has commenced. Regular use of hair cosmetics that contain alcohol can strongly increase FAEEs in hair, which can influence the results to show excessive alcohol consumption.

A basic level of FAEE is measured in everyone’s hair, even of those who are teetotal. FAEE and EtG complement one and other with respect to their different sensitivity to hair cosmetics, for example, false positive FAEE results due to use of hair cosmetics containing ethanol would not be confirmed because the same specimen would have a negative EtG result.

Please note that although body hair can be used for analysis, a minimum of 1cm from root is required and Axilla (underarm) hair CANNOT be used for alcohol detection.