- THC is an acronym for tetrahydrocannabinol, the psychoactive component in cannabis products.
- THC is absorbed in the bloodstream and binds itself to hair follicles.
- Factors that impact how long THC will be detected in your hair include frequency of use, metabolism, hair health, and hair color.
- THC can stay in your hair on average for up to 90 days.
While cannabis usage has become less taboo and more accepted, many people don’t know that the effects of THC can linger in your system long after consumption. This applies to saliva, urine and blood tests, and hair tests.
THC tests can be used for long-term drug use or even be part of a pre-employment screening process. Knowing how long THC can stay in your hair may help you decide whether or not to consume cannabis products.
What Is THC?
THC, also known as tetrahydrocannabinol, is the primary psychoactive component in cannabis  responsible for altering normal states of consciousness. It gives users the “high” they’re seeking when taking cannabis or cannabis-based products.
When cannabis is consumed, THC is absorbed in the bloodstream and travels to the brain. Once there, it binds to CB1 receptors responsible for cognitive processes, memory, and pleasure.
THC Metabolism and Hair Growth
Whether you’re a seasoned smoker, a first-time user, or simply curious about the topic, understanding how THC is metabolized and its relationship to hair growth is essential.
To better understand how and why THC appears in your hair, you must first know how the body metabolizes THC.
As THC is absorbed in your bloodstream , a chain reaction occurs in the body’s endocannabinoid system. This system affects different organs and systems, including the heart, lungs, liver, brain, vascular system, and muscles.
As the liver metabolizes THC, it produces over 80 metabolites, one of which is THC-COOH. This metabolite is fat-soluble and will remain in the body longer than other metabolites, as it can be stored in fatty tissue.
As the metabolites are circulated throughout the body, they eventually end up in your hair follicles and build up in your hair shafts for quite a long time.
How Long Does THC Stay In Your Hair?
On average, TCH can be detected on hair samples for up to 90 days after the last consumption of cannabis-based products. However, this timeline can vary significantly based on a variety of factors.
Factors That Impact How Long THC Stays In Your Hair
Frequency of Use
How often you consume cannabis and the amount will impact how long THC stays in your system and how long it will stay in your hair. For example, if you consume cannabis regularly and in high doses, THC will remain in your system and hair longer than if you only use it occasionally or take small amounts.
Your metabolism is a primary factor in how quickly THC can be absorbed and removed from your body. Everyone’s metabolism is different, and the speed at which your body can process any type of substance might be very different from one person to the next.
Faster metabolisms usually have shorter detection windows than those with a slower metabolism. Typically, increased physical activity and staying hydrated help to promote a healthier metabolism and can help to flush out THC faster.
People may not think their hair health impacts how long THC stays in their hair, but it does. Healthy hair is better at retaining metabolites than unhealthy or damaged hair. This is because THC is stored in the hair’s cortex and can be detected until the hair is shed or cut.
Surprisingly, the color of your hair can also affect how long you can detect THC in hair follicles. THC is easier to detect in darker hair colors like black and brown. This is because melanin, the pigment found in darker hair colors, helps act as a binding agent for THC.
As a result, individuals with lighter hair colors will typically see a shorter detection window than those with darker hair.
How Hair Follicle Tests are Used to Detect THC
Employers and law enforcement officials often use hair follicle tests  to detect THC in an individual’s system. They are non-invasive, relatively inexpensive, and, most importantly, extremely accurate.
In a hair follicle test, a small sample of your hair is taken from near the scalp and tested for THC metabolites. The sample is then sent to a lab for further testing, and the results are usually available within 2-3 weeks.
Hair follicle tests can provide an accurate picture of long-term cannabis use, as THC metabolites can be stored in your hair for up to 90 days after consumption. This makes them perfect for employers and law enforcement officials trying to detect illegal substance use.
Frequently Asked Questions
Below are some of the most frequently asked questions regarding THC.
THC stands for “tetrahydrocannabinol.” It is the psychoactive component found in cannabis products that are responsible for the intoxicating, or “high,” feeling it produces in the body.
The legality of THC depends on the area you live in. Cannabis is becoming increasingly accepted as a legal substance in different countries and states. While cannabis consumption may be permitted in some areas, it may be restricted to only medicinal uses, while in other places, it is also legal for recreational purposes.
THC can produce various psychoactive effects, including altered mood, sensory perception, and cognitive function. It can also create a sense of euphoria, relaxation, and increased appetite. However, it can have adverse side effects, such as anxiety, paranoia, hallucinations, memory impairment, and impaired coordination. .
There are many ways to consume THC. Smoking cannabis flower remains to be the most common way to consume THC. However, an increasing variety of alternatives are also available, such as vaporizing, consuming edibles, tinctures, or oils, and using topicals, concentrates, and patches.
It is rare to experience a THC overdose. However, overconsumption in the form of edibles or concentrates can cause severe anxiety and paranoia, hallucinations, confusion, and disorientation that may require medical attention.
In terms of addiction, THC is not considered to be physically addictive. However, some individuals may develop a mental dependence or a cannabis use disorder over a more extended period of use.
Frequently consuming high levels of THC may contribute to adverse physical and psychological effects, such as difficulties with memory and attention and a higher risk of experiencing mental health issues.
 U.S. Department of Health and Human Services. (n.d.). Cannabis (marijuana) and cannabinoids: What you need to know. National Center for Complementary and Integrative Health. Retrieved from https://www.nccih.nih.gov/health/cannabis-marijuana-and-cannabinoids-what-you-need-to-know on 2023, May 2.
 Sharma, P., Murthy, P., & Bharath, M. M. S. (2012). Iranian journal of psychiatry. Chemistry, metabolism, and toxicology of cannabis: Clinical implications. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570572/ on May 2, 2023
 Taylor, M., Lees, R., Henderson, G., Lingford-Hughes, A., Macleod, J., Sullivan, J., & Hickman, M. (2017, March). Drug and alcohol review. Comparison of cannabinoids in hair with self-reported cannabis consumption in heavy, light and non-cannabis users. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5396143/ on May 2, 2023