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How long does Delta 9 last in your urine?

Delta 9 tetrahydrocannabinol (Δ9-THC), more commonly known as Delta 9, is the main psychoactive compound found in cannabis. Delta 9 produces the “high” associated with marijuana use. Since Delta 9 is metabolized and excreted over time, it can be detected in urine drug tests for 1-30 days after last use.

What is Delta 9 THC?

Delta 9-tetrahydrocannabinol (Δ9-THC) is one of over 100 cannabinoids found in the cannabis plant. Delta 9 THC mimics the effects of anandamide, a neurotransmitter produced in the body that binds to cannabinoid receptors in the brain. This interaction causes the intoxicating effects of cannabis such as euphoria, relaxation, altered perception of time, impaired memory, and increased appetite.

Delta 9 THC is the main psychoactive compound in cannabis that produces the “high” associated with marijuana use. It is found in the leaves, stems, flowers, and seeds of both hemp and marijuana plants. However, marijuana contains much higher concentrations of Delta 9 THC compared to hemp.

How is Delta 9 THC metabolized and excreted?

When Delta 9 THC enters the body, it is distributed rapidly to tissues due to its high lipophilicity or affinity for fat. The metabolism of Delta 9 THC begins in the liver where it undergoes hydroxylation and oxidation by enzymes such as cytochrome P450 (CYP450). This produces multiple active metabolites such as 11-hydroxy-Δ9-THC which also has psychoactive effects.

Delta 9 THC and its metabolites are initially metabolized in the liver and later redistributed to fatty tissues and organs throughout the body. The compounds are highly lipid soluble and accumulate in fatty tissues. With repeated or chronic marijuana use, Delta 9 THC can accumulate in fat stores and be released back into the bloodstream slowly over time.

Delta 9 THC and metabolites are primarily excreted in urine and feces. Delta 9 THC undergoes enterohepatic recirculation where it is excreted in bile by the liver, reabsorbed by the intestines, and returned to the liver. This delays the elimination of THC as the compounds can go through this cycle multiple times before being fully excreted.

How long does Delta 9 THC stay in your system?

The length of time Delta 9 THC remains detectable in the body depends on factors such as:

  • Amount and potency of cannabis used
  • Frequency of use (chronic vs occasional)
  • Method of use (inhaled vs ingested)
  • Metabolism and body fat content
  • Fluid intake and hydration levels

Delta 9 THC is fat-soluble and accumulates in fatty tissues with repeated use. Frequent and chronic cannabis users retain Delta 9 THC in their system for longer periods than occasional users. Heavy cannabis use causes THC to build up in fat stores and be released back into the bloodstream slowly over days or weeks.

Delta 9 THC may be detectable in the system anywhere from a few days up to a month after last use. However, detection windows can sometimes be longer with chronic, heavy use. Here is an overview of how long Delta 9 THC remains detectable in the body through various testing methods:

In blood

Delta 9 THC may be detectable in blood for:

  • Single use: 1-2 days
  • Moderate use: up to 1 week
  • Heavy use: up to 3 weeks

In saliva

Saliva tests detect recent use of Delta 9 THC and may be positive for:

  • 1-3 days after single use
  • Up to 29 days with heavy, chronic use

In urine

Urine tests are the most common way to test for Delta 9 THC use. It may be detected in urine for:

  • Single use: 3-8 days
  • Moderate use: 5-15 days
  • Heavy use: 10-30 days
  • Chronic heavy use: 30-45 days

In hair

Hair follicle tests can detect regular or heavy Delta 9 use for up to 90 days. However, they are not commonly used for employment screening or drug testing.

Factors that influence how long Delta 9 THC stays in urine

Many variables affect the detection window for Delta 9 THC urine tests. These include:

Frequency and amount of use

With repeated or chronic cannabis use, Delta 9 THC accumulates in fat stores and is released back into the bloodstream slowly. Frequent users will likely test positive for much longer than occasional users.

Delta 9 THC potency

Higher potency cannabis contains greater concentrations of Delta 9 THC. Marijuana can contain 5-30% THC while hashish may have up to 80% THC content. Potency impacts the detection window.

Individual variation

A person’s age, gender, metabolism, hydration levels and more affect how quickly they excrete THC. Younger people with fast metabolisms may clear Delta 9 THC quicker than older people.

Fluid intake

Drinking more fluids can dilute urine and shorten the detection window. However, fluid loading is unlikely to cause a negative test result for chronic marijuana users.

Does secondhand exposure affect Delta 9 urine tests?

It’s unlikely that secondhand exposure to marijuana smoke would cause a positive urine test result. Research shows that very little THC is absorbed through passive inhalation. In one study, participants exposed to secondhand marijuana smoke for 3 hours in an unventilated room tested negative for THC urine screening.

However, passive exposure may possibly cause very low urine THC concentrations in the 1-15 ng/mL range. The cutoff level for a positive urine screening is usually 50 ng/mL. So secondhand exposure is unlikely to produce a false positive on a drug test.

How to pass a Delta 9 THC urine test

Here are some tips for passing a urine drug test for Delta 9 THC:

  • Drink plenty of water before the test to dilute urine
  • Exercise to increase metabolism and excretion
  • Don’t exercise or diet excessively right before the test
  • Take B vitamins to color diluted urine
  • Consider abstaining from marijuana use for 30-90 days
  • Do not use adulterants or substitutions which are easily detected

While home remedies abound, abstaining from use for at least 30 days is the only sure way to pass a urine drug test. Using adulterants or diluting urine is detectable and will invalidate the test results.

Typical Delta 9 THC urine drug test protocol

Delta 9 THC urine drug screens follow standard testing protocols. Here are the typical steps:

  1. Provide urine sample under supervision
  2. Sample divided into two aliquots
  3. First aliquot is screened for THC metabolites
  4. Positive screening result leads to confirmatory GC/MS test
  5. GC/MS used to quantify THC metabolite concentrations
  6. Results interpreted based on cutoff levels for positive result

Initial urine screens use immunoassay tests that target the THC metabolite THCA. Confirmatory GC/MS testing accurately identifies and quantifies concentrations of THC metabolites relative to established cutoff levels.

Urine drug test detection levels

Here are typical cutoff levels for cannabis on urine drug screens:

  • Screening immunoassay – 50 ng/mL of THCA
  • GC/MS confirmation – 15 ng/mL of THCA

Urine samples that screen positive typically undergo GC/MS testing. This method uses a lower 15 ng/mL cutoff for a positive confirmation.

Table summarizing Delta 9 THC detection window in urine

Frequency of Use Detection Window
Single use 3-8 days
Moderate (2-4 times per week) 5-15 days
Heavy (daily) 10-30 days
Chronic heavy use 30-45 days


Delta 9 THC can be detected in urine anywhere from 3-30 days after last use depending on factors such as frequency of use. Chronic heavy cannabis use may result in positive tests for over a month after last use. While Delta 9 THC is excreted from the body relatively quickly, it can accumulate in fat stores and be released back into the urine in trace amounts over extended periods.

The most reliable way to pass a Delta 9 urine drug test is abstaining from marijuana use for a minimum of 30 days. Drinking fluids can help dilute urine, but is not foolproof. Adulterating urine samples is risky and detectable. Understanding the typical testing protocols and cutoff levels can help marijuana users better gauge their likelihood of testing positive.