Understanding the Hair Drug Test Detection Window

What is the Detection Window?

A hair drug test can detect drug use up to 90 days before, making it an effective tool for employers and legal agencies. This long detection window is due to the hair's slow growth rate.

Why 90 Days?

The detection window of 90 days is possible because hair grows at a rate of about half an inch per month. Each segment of hair represents a different time frame, with the most recent growth closest to the scalp.

Limitations and Considerations

It's important to note that the detection window can vary based on the drug, the individual's hair growth rate, and the amount of drug used. Hair drug tests are not infallible and should be used in conjunction with other testing methods for a comprehensive approach.