If you’re facing a hair follicle drug test, you’re likely wondering just how long traces of cannabis can be detected. Unlike other tests that measure recent use, a hair test can look much further back into your history. It’s a common concern for many, and getting accurate information is the first step to understanding your situation.
The science behind this test is fascinating. When you consume cannabis, its metabolites enter your bloodstream and eventually find their way to the hair follicles. As your hair grows, these markers become trapped inside the hair shaft, creating a timeline of your substance use.
The 90-Day Detection Window for Hair
The most frequently cited timeframe for how long weed stays in your hair is approximately 90 days. This is because the standard hair test analyzes the 1.5 inches of hair closest to your scalp, which represents about three months of growth. If you’ve used cannabis within that period, it’s likely to show up. However, this isn’t a perfect clock. Factors like your hair growth rate, how much you use, and your individual metabolism can all influence this window.
What a Hair Follicle Test Actually Looks For
It’s important to know that the test isn’t looking for THC itself. Instead, it’s designed to detect the metabolites your body creates after you consume cannabis. These tiny chemical byproducts are what get deposited in your hair follicle from your bloodstream. Because they’re embedded inside the hair shaft, they are protected from most external contaminants and standard shampoos, making this a very reliable method for detecting past use.
Can You Remove THC from Your Hair?
Many people search for quick fixes or special shampoos to “clean” their hair. The truth is, because the metabolites are inside the hair strand, most over-the-counter products are ineffective. While some specialized, high-strength detox shampoos exist, their success is not guaranteed and often requires strict, multi-step processes. For the most accurate results, the best approach is to be informed about the test’s capabilities and timelines.
Ultimately, the hair follicle test provides a long-term look at substance use, with a typical detection window of up to 90 days. Knowing how this process works can help you better understand what to expect and how to prepare.