Whether you’re a THC user or not, there can be a variety of reasons you might want to know how long delta-9 stays in your system. It’s the cannabinoid targeted by drug tests, since it’s the primary substance that indicates marijuana use.

Even those who inhale secondhand marijuana smoke or use CBD products are potentially at risk of failing urine tests and other types of tests if they don’t know how long weed stays in your system. In this guide, learn everything you need to know regarding drug testing for marijuana and how it pertains to delta-9 THC — with a special focus on understanding how long THC stays in your body after use and why.

What is Delta-9 THC?

Delta-9 tetrahydrocannabinol (delta-9, D9, THC) is an intoxicating cannabinoid that occurs naturally in Cannabis sativa. The primary constituent in cannabis, THC, is illegal in many places worldwide due to drug laws.

In addition, many employers screen for drug use even when not explicitly required to by law. THC is a common target of workplace drug tests due to cultural stances on THC use and persistent federal laws.

Like all cannabinoids, delta-9 is a lipoid molecule, which means it takes a long time to dissolve and stays in your body’s fatty tissues until it does. As a result, THC can remain in your body for up to 30 days, making testing positive for delta-9 a significant concern for countless individuals spread across all strata of society.

Delta-9 vs. Weed

The terms “delta-9” and “weed” are often used interchangeably, but there are slight differences between their meanings. “Weed” is derogatory slang used to refer to any type of cannabis product. “Delta-9,” on the other hand, refers specifically to delta-9 tetrahydrocannabinol, the primary active compound in “weed.”

So, when someone says they’re “smoking weed,” what they’re really doing is flooding their system with delta-9. This cannabinoid can make its way into your system even if you never use marijuana and stay away from people who do. Full-spectrum CBD products, after all, contain enough THC to potentially cause a false positive on a drug test.

How Long Will Delta-9 Stay In Your System?

On average, delta-9 THC will stay detectable in the human body for 7-30 days after use. There are quite a few different factors involved in calculating how long THC will remain in your system, however, which we will cover in detail as we continue.

For the average person, all you need to know is that the “safe” window for THC testing does not begin for a full 30 days after the last time you ingested any amount of THC. If you’re concerned that you might test positive for THC soon, dive deeper with us to examine all the variables at play.

What is the Half-Life of Delta-9?

According to a 2012 study published in the Iranian Journal of Psychiatry, the average half-life of THC is 5-13 days for frequent users and around a day for infrequent users. This study uses the term “half-life” in its biological context, which refers to the amount of time it takes the human body to eliminate half of a substance it ingests.

So, half of the delta-9 you consume should leave your system in around 14 days, even if you use the cannabinoid frequently. Half of 30 days is approximately 14 days, so the half-life of THC observed in scientific research aligns with overall wisdom regarding the length of time delta-9 lasts in your system.

Keep in mind that the Iranian study we just cited only included an average amount of time it takes half the THC you ingested to be processed by your body. A variety of factors can impact individual outcomes, such as:

Frequency of Use

As the 2012 study noted, there are vast differences in THC half-life between those who use the cannabinoid frequently and those who do not. In infrequent users, large doses of delta-9 have been shown to be processed within 1-3 days almost universally ever since hospitals and research institutions started keeping such cannabis statistics.

What are the implications? Essentially, as long as you have not used cannabis anytime recently, it is possible to take even a large dose of delta-9 but still test clear even a few days later. Only as you continue to use THC that the cannabinoid starts to build up in your fatty tissues, eventually processed out but very slowly.

Age and Physiology

Younger bodies tend to detoxify faster, and the healthier you are, the better able your body will be to remove substances like THC. If you are over the age of 60, expect THC to leave your system slightly slower than it would leave the body of a 30-year-old. Similarly, individuals with a higher body mass index may also notice THC taking its time to leave their systems.

THC Potency

The potency of the delta-9 products you use dramatically impacts how much THC you ingest and how long that THC stays in your body. Someone who uses 1 gram of cannabis flower containing 15% THC per day, for instance, will ingest considerably less THC over the course of a week than a person who uses 1 gram of cannabis concentrate containing 90% delta-9 daily.

How Long Can Delta-9 Be Detected?

The length of time delta-9 can be detected in the human body depends just as much on the type of biological sample being tested as it does on the THC use habits of the individual in question. Delta-9 remains present in certain biological tissues much longer than it does in others, something you should be well aware of when approaching the issue of delta-9 drug testing:

How Long Does Delta-9 Stay in Urine?

Most drug tests are conducted using urine, whether for law enforcement, workplace, or scientific reasons. Delta-9 generally remains detectable in urine for 1-30 days after use, with all THC traces no longer present in this type of sample past that period. Urine tests are considered to be quite accurate but notably lack the ability to detect cannabis use in the past 30 days.

How Long Does Delta-9 Stay in Saliva?

Saliva tests have recently come into common usage as tools to detect marijuana use that has occurred within the last few hours. THC does not remain in your mouth very long. However, delta-9 saliva tests are usually only considered accurate when administered within around a 12-hour window.

How Long Does Delta-9 Stay in Blood?

Blood tests are not commonly used to detect delta-9 usage since they are only capable of detecting THC use that occurred within around a 36-hour window. Essentially, as soon as the effects of THC wear off for the user, it becomes difficult to detect in their blood. Delta-9 blood tests for detecting marijuana are usually only administered in a hospital environment.

How Long Does Delta-9 Stay in Hair?

At around 90 days, hair tests provide the longest window of delta-9 detection of any drug testing method. If you are subjected to a THC hair test anytime within three months of the last time you used delta-9, there’s a chance that a trace will still be left in the roots or follicles. THC doesn’t become present in your hair until about a week after you use it, though, so hair tests have to be administered a while after alleged delta-9 use to be considered accurate.

Will 0.3% Delta-9 THC Show Up on a Drug Test?

There is a small chance that the tiny amount of delta-9 THC present in full-spectrum CBD products (up to 0.3%) might accumulate to the extent that it becomes detectable in drug testing. It is usually possible, however, to establish that a false positive for THC does not necessarily constitute substance abuse, especially in these days in which hemp is a household item once again.

How to Flush Delta-9 THC from Your System

Any expert will tell you that the only way to flush THC out of your system is to allow your body’s natural processes to take place. There may be certain ways you can accelerate the natural functioning of your body, however, to flush THC out of your system faster than it would normally be excreted. Just be cautious of “detox products” and other fast-acting methods that can end up doing more harm than good.

Ways to Get Delta-9 Out Of Your System Faster

Here are the top 4 methods you can use to get delta-9 out of your body:


Water is the primary substance your body uses to purify itself. Make sure it has plenty of water to carry THC molecules out of your system.


The vast majority of the detoxification process occurs while you sleep. Make sure to sleep 8-9 hours each night for ideal THC excretion levels.

Fibrous Foods

Foods that are high in fiber promote proper elimination, aiding in detoxification. Start with some fruits and leafy greens.

Detox Products

Be very wary of detox products, especially those designed especially for delta-9, since they can (ironically) be very toxic and harmful. A cup of detox tea won’t hurt, though, and it will help keep you hydrated.

Conclusion: How Long Does It Take for Delta 9 To Clear Your System?

All things considered, delta-9 should clear your system in a week for infrequent users and within 30 days for chronic users. Take proper time to study all the different variables that might impact the length of time THC remains in your system, and tread with caution as you do your best to continue flying under the radar.