Test tubes in a rack with sample being taken from one of them

Drug and Alcohol Detection Times in Hair: An In-depth Overview

In the UK, drug and alcohol testing is crucial in various sectors, from employment screenings to forensic investigations. One of the most reliable and comprehensive methods used for this purpose is hair follicle drug testing. This method offers a more extended detection window compared to other tests like urine or blood tests. In this article, we'll explore the intricacies of drug and alcohol detection times in hair, the relevance of cut-off levels, and how infrequent drug use might affect the results.

Understanding Hair Follicle Drug Testing

A hair follicle drug test involves analysing a small sample of hair to detect the presence of drugs and their metabolites. Drugs and their by-products, once consumed, enter the bloodstream. As hair grows, these substances are incorporated into the hair shaft, effectively creating a chronological record of drug use.

Why is Hair Drug Testing Used in the UK?

The UK employs hair follicle drug testing for several reasons:

  1. Long Detection Window: This method provides a detection window of typically up to 6 months but can be more, whereas urine and blood tests might only reveal drug use within days or weeks.
  2. Less Invasive: Collecting a hair sample is less intrusive than a blood test.
  3. Hard to Cheat: It's difficult to adulterate or substitute a hair sample compared to urine samples.
  4. Detailed Drug Use History: Hair testing can provide patterns of drug use, distinguishing between infrequent and regular users.

Infrequent User vs. Regular User

An infrequent user might have lower drug levels in their hair compared to regular users. The hair follicle drug test for an infrequent user might sometimes fall below the cut-off levels, leading to a negative result, even if drug use occurred. However, it's essential to understand that even if drug use was occasional, it could still be detected, especially if consumption was heavy.

What is the Hair Follicle Drug Detection Time

Hair growth in humans averages about 1cm per month. Consequently, a 3cm segment of scalp hair provides an insight into drug consumption over the preceding three months. To glean insights into extended periods of drug use, we analyze consecutive hair segments, typically in 1cm or 3cm lengths.

Drugs, upon entering the bloodstream, are incorporated into the hair follicle. As the hair grows, minute quantities of these drugs get embedded within the hair strand. The depth of this testing often astonishes many, leading them to wonder, "How extensive is the period covered by hair drug testing?" To put it succinctly, the retrospective period is as long as the length of the hair strand. For instance, while a 3cm hair segment reveals about three months of drug history, a 12cm strand can illuminate drug consumption over an entire year.

Our testing covers a range of drugs and substances, including but not limited to Benzodiazepines, Cannabis, Cocaine, Ecstasy (MDMA), Ketamine, Mephedrone (M-Cat), Methadone, Methamphetamine, and Opiates like Heroin.

When drugs are consumed, the body processes them to produce metabolites, which serve as direct evidence of drug ingestion. Our specialized team meticulously examines hair samples to pinpoint these drug traces and their corresponding metabolites. Based on our laboratory findings, we furnish an authoritative interpretation of the drug levels identified.

Detailed Analysis Approaches:

  • Month-by-Month Analysis: This approach involves segmenting the hair sample into 1cm sections, each representing an estimated month of growth. Through this, we can generate a month-wise drug consumption profile. Such granular analysis can shed light on patterns, be it an uptick or a decline in drug levels, and even uncover sporadic, minimal drug use.

  • Overview Analysis: This method focuses on a broader three-month timeframe using a 3cm hair segment, mapping out drug consumption during that span. We can further extend this analysis by studying successive 1cm or 3cm sections, depending on the hair's length. For instance, a comprehensive review of a 12cm hair sample can chronicle drug habits over an estimated year.

To sum it up, the question, "How extensive is the period covered by hair drug testing?" has a straightforward answer: the limit is virtually boundless. Essentially, every centimetre of hair offers a window into a month of potential drug use.


Hair follicle drug testing offers an efficient and reliable method for detecting drug and alcohol use over an extended period. In the UK, its applications are diverse, reflecting its accuracy and the detailed insights it provides into an individual's drug use history. Whether you're an employer, legal professional, or someone seeking personal clarity, understanding the nuances of hair drug testing is invaluable.

Collection list

Alcohol Tests
Alcohol Tests

Alcohol Tests

Drug Tests
Drug Test

Drug Tests

Postal Tests
home drug test kit

Postal Tests

Chain of Custody Drug Tests
chain of custody drug test

Chain of Custody Drug Tests

Patient Reception

76 Wimpole Street, London.

W1G 9RT.

Monday-Friday: 7AM - 7PM

Saturday: 7AM - 1PM

Sunday: Closed