What is the Window of Detection for Drugs in a Hair Test?

Lately, hair testing has become known as an effective way to identify drug and alcohol abuse, especially if a longer-term snapshot is needed. Hair holds onto biomarkers that indicate the long-term usage of drugs and alcohol when it is taken close to the scalp. This means that a sample of hair can show up to a three-month record of any substance abuse. Hair provides an easy sample to collect and is hard to tamper with.

For a hair drug test, a sample of about 200 strands of hair (the size of a #2 pencil) close to the scalp must be collected for screening and confirmation test. If scalp hair is not available, any other kind of hair (facial, axillary, etc.) may be collected in the same amount. When referring to head hair, this means scalp hair only; body hair refers to all other kinds.

Line chartWindow of Detection: Analysis of hair provides a much longer detection window than other specimens. It takes 7-14 days for drug and alcohol biomarkers to be deposited into the hair root and emerge past the scalp.

Head hair can detect up to 90 days of drug abuse, and body hair can detect up to 180 days. Body hair does not grow as fast as head hair, therefore the biomarkers trapped will provide a longer window of detection.

Pros and Cons of a Hair Drug Test: Some of the pros and cons to consider while choosing a hair drug test.


  • Observed collection
  • Long detection window
  • Does not deteriorate
  • Can be used to measure chronic drug use
  • Convenient shipping and storage
  • More difficult to adulterate than urine


  • Moderate to high cost
  • Cannot be used to detect drug used 1-14 days prior to drug test
  • External contamination like bleach used on the hair can cause a false negative result.

Turnaround Time: Results for a hair drug test take approx. 3-5 business days.

At ARCpoint Labs of Worcester, we offer hair follicle drug testing. We have 5-17 drug testing panels including EtG (alcohol). Click HERE to schedule your appointment today or call us at 508.796.5303.

ARCpoint Labs of Southboro-Framingham provides food allergy and food sensitivity testing to many nearby communities including Auburn, Boylston, Clinton, Millbury, Northborough, Shrewsbury, West Boylston, Acton, Hudson, Bolton, and Stow.