--- title: "How long does a hair follicle drug test show" description: "How long does a hair follicle drug test show drugs? Hair follicle tests detect drug use up to 90 days. For accurate testing, call (877) 731-6362." author: "AMH Nationwide" date: "2026-08-28" tags: ["how long does a hair follicle drug test show", "how long does a hair follicle drug test show | how long does a hair follicle test show drugs"] canonical: "https://amhnationwide.com/how-long-does-a-hair-follicle-drug-test-show/" last_updated: "2026-08-28" --- # How long does a hair follicle drug test show **By AMH Nationwide** | August 28, 2026 How long does a hair follicle drug test show drugs? Hair follicle tests detect drug use up to 90 days. For accurate testing, call (877) 731-6362. --- How long does a hair follicle drug test show drug use? Hair follicle drug tests can detect drug metabolites in hair samples for up to 90 days after use. This extended detection window makes hair testing useful for employers, courts, and probation agencies. Call (877) 731-6362 to arrange a test through AMH Nationwide. OVERVIEW ## What is the detection window for a hair follicle drug test? The [detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/) for a hair follicle drug test is typically up to 90 days. Hair grows approximately half an inch per month, and the standard test analyzes about 1.5 inches of hair closest to the scalp. This length corresponds to roughly three months of drug use history. Standard detection period: 90 days Hair growth rate: ~0.5 inches per month Sample length analyzed: 1.5 inches from scalp TEST DETAILS ## How does a hair follicle test detect drug use? A hair follicle drug test detects drug metabolites deposited in the hair shaft from the bloodstream. As hair grows, it incorporates trace amounts of substances used, allowing for a historical record of drug consumption. The test identifies metabolites of various drugs including amphetamines, cocaine, marijuana, opioids, and PCP. Detects drug metabolites embedded in hair shaft Reflects drug use over past 90 days Common drugs tested: amphetamines, cocaine, marijuana, opioids, PCP TESTING PROCESS ## How is hair collected and processed for drug testing? Hair samples are collected at authorized collection sites coordinated by AMH Nationwide. A small amount of hair, usually from the crown of the head, is cut close to the scalp. The sample is then sent to one of five national labs: [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, or ExperTox for analysis. All non-negative results are reviewed by a certified Medical Review Officer to ensure accuracy and proper interpretation. TEST APPLICABILITY ## Who typically orders hair follicle drug tests and why? Hair follicle drug tests are commonly ordered by employers, courts, [probation](https://amhnationwide.com/hair-follicle-drug-test-probation/) agencies, and other entities requiring long-term drug use history. Because of its 90-day detection window, it is preferred when recent and past usage information is needed. It is not used for Department of Transportation (DOT) safety-sensitive testing, which requires [urine](https://amhnationwide.com/urine-drug-testing/) testing under federal protocols. ## Schedule Your Hair Follicle Drug Test Today To ensure accurate and reliable results for hair follicle drug testing with certified lab analysis and Medical Review Officer oversight, call (877) 731-6362. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) LIMITATIONS ## Can a hair follicle drug test detect one-time or passive exposure? Hair follicle tests can detect even single instances of drug use if the hair sample includes the growth period during which the drug was consumed. However, passive exposure, such as being in a room with drug smoke, typically does not result in positive results because metabolites must be incorporated internally into the hair shaft rather than externally deposited. PRICING & ORDERING ## How much does a hair follicle drug test cost and how do I arrange testing? The cost of a hair follicle drug test varies based on the drug panel selected and detection window required. AMH Nationwide does not offer online ordering; instead, contact us by phone to discuss your testing needs and obtain a quote. Call (877) 731-6362 to schedule your hair follicle drug test at one of over 20,000 nationwide collection sites. AMH Reviewed & Maintained By AMH Nationwide Customer Service AMH Nationwide is BBB A+ accredited and routes every order through Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox, all of which use multiple lab certification agencies and standards such as [SAMHSA](https://www.samhsa.gov/workplace/drug-testing)-aligned laboratory protocols, the ANSI National Accreditation Board for forensic testing and calibration, the College of American Pathologists (CAP), and Clinical Laboratory Improvement Amendments (CLIA). Every non-negative screen is reviewed by a certified Medical Review Officer as part of standard processing before a result is released, and chain-of-custody documentation is maintained on every collection. This page does not constitute medical or legal advice. **Last updated:** July 2026 You May Also Need [Nail Drug TestingNo head or body hair available? A 5-panel fingernail test covers a similar look-back window.Learn more →](https://amhnationwide.com/5-panel-fingernail-drug-test/)[ChildGuard: Environmental ExposureConcerned about a child or loved one? ChildGuard screens for exposure to drugs in their environment.Learn more →](https://amhnationwide.com/5-panel-hair-drug-test-environmental-exposure-childguard/)[Shorten the Detection WindowShortened options like 30 and 60 day hair panels are also available, useful when a urine test’s 1-3 day window is too short.Learn more →](https://amhnationwide.com/30-day-hair-drug-test/)[Hair ETG Alcohol TestAlso need alcohol testing? The hair ETG test screens for alcohol use, and can be added to the same collection.Learn more →](https://amhnationwide.com/etg-and-peth/) Frequently Asked Questions ## Common Questions Hair follicle drug tests typically detect drug use starting about 5 to 7 days after consumption, once the hair containing drug metabolites grows above the scalp. Yes, the standard 1.5-inch hair sample reflects approximately 90 days of drug use. Shorter hair samples may reduce the detection window accordingly. Hair treatments such as dyeing or bleaching can potentially reduce drug metabolite concentrations but do not guarantee a negative test. Labs account for such factors during analysis. No, DOT-regulated safety-sensitive testing requires federally certified urine testing under [49 CFR Part 40](https://www.transportation.gov/odapc/part40). Hair follicle tests are used for non-DOT purposes. All non-negative hair follicle test results are reviewed by a certified Medical Review Officer to confirm findings and rule out alternative explanations before final reporting. It is highly unlikely. Hair follicle testing detects internalized drug metabolites, so passive exposure generally does not cause positive results. Sources • [SAMHSA – Mandatory Guidelines for Federal Workplace Drug Testing Programs](https://www.samhsa.gov/workplace/drug-testing) • [U.S. DOT – 49 CFR Part 40 – Procedures for Transportation Workplace Drug and Alcohol Testing Programs](https://www.transportation.gov/odapc/part40) • [CDC – National Center for Health Statistics – Drug Use FastStats](https://www.cdc.gov/nchs/fastats/drug-use.htm) • [Quest Diagnostics – Employer Solutions, Hair Testing Methodology](https://www.questdiagnostics.com/) • [LabCorp – Occupational Testing Services](https://www.labcorp.com/) ## Ready to get started? AMH Nationwide provides the lab order and arranges collection nationwide. Every non-negative result reviewed by a certified Medical Review Officer. Call (877) 731-6362 or contact us. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) --- **Need a drug, alcohol, HIV or STD test?** AMH Nationwide is a national lab testing agency operating since 2004, with more than 20,000 collection sites across the United States. Hair, urine, fingernail and blood testing, panels from 5 through 19, for individuals and employers. - Call: (877) 731-6377 - Find a collection site: https://amhnationwide.com/locations/ - Full page: https://amhnationwide.com/how-long-does-a-hair-follicle-drug-test-show/