A “weed cart,” short for THC vape cartridge, is a device containing highly concentrated cannabis oil intended for inhalation. These concentrates are significantly more potent than traditional cannabis flower, often containing 70% to 90% tetrahydrocannabinol (THC). The high concentration and the method of inhalation result in a rapid and substantial delivery of THC to the bloodstream. This rapid delivery is a primary factor influencing how long traces of the substance remain detectable. The duration that a weed cart stays in a person’s system is not fixed and is subject to wide variability based on individual biology and the specific testing method employed.
How Vaping Concentrates Affect THC Metabolization
The body screens for the inactive metabolite, 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH), rather than the active compound, delta-9-tetrahydrocannabinol (THC). The liver processes THC into this metabolite, which is fat-soluble and stored in the body’s fat cells. Vaping concentrates deliver a much larger initial dose of THC compared to smoking flower, creating a higher initial saturation in the blood. This high-concentration delivery means the liver must process a greater overall quantity of the compound. The resulting elevated production and storage of THC-COOH prolongs the elimination process, as this larger metabolite load must be slowly released from fat cells and excreted.
Detection Windows Based on Testing Method
The length of time THC metabolites are detectable depends heavily on the specific biological sample collected for testing. Each testing method targets different compounds or parts of the body, leading to vastly different detection windows.
Urine Testing
Urine testing remains the most common method, primarily detecting the inactive metabolite THC-COOH. For an infrequent user, the metabolite is typically detectable for about three to seven days. For chronic daily users, the build-up of metabolites in fat reserves extends this detection window substantially. Heavy, long-term users may continue to test positive for 30 days or even longer after their last use.
Blood Testing
Blood testing measures the active THC compound in the bloodstream, generally used to determine recent use or current impairment. The detection window is short, usually spanning only a few hours up to one or two days for occasional users. For chronic consumers, THC can sometimes be detected for up to seven days, but this test is a poor indicator of historical use.
Saliva Testing
Saliva, or oral fluid, testing is used in workplace and roadside testing environments due to its ease of collection and focus on very recent consumption. This method detects THC remaining in the oral cavity after inhalation. The detection window typically ranges from 24 to 72 hours following the last use. In cases of heavy, frequent consumption, THC may be detectable for up to seven days.
Hair Follicle Testing
Hair follicle testing offers the longest detection window, assessing historical use rather than recent consumption. This test analyzes the segment of hair closest to the scalp, which traps circulating metabolites. Since head hair grows slowly, the standard 1.5-inch sample provides a retrospective detection window of up to 90 days. The presence of THC-COOH in the hair indicates use over the three months preceding the test.
Variables That Determine Individual Clearance Rate
The wide ranges provided for detection windows exist because numerous biological and behavioral factors unique to each person influence the clearance rate of THC metabolites.
Frequency and Duration of Use
The single most important factor is the frequency and duration of use. Occasional users clear the substance much faster because the THC-COOH does not have time to build up significant stores in the body’s tissues. Conversely, chronic, heavy use of a vape cart causes a cumulative build-up of the fat-soluble metabolites, leading to a much slower release and an extended detection window that can last for weeks or months.
Metabolic Rate
Metabolic rate plays a significant role, as individuals with faster metabolisms break down and process substances more quickly. A higher metabolic rate can accelerate the conversion of THC into the metabolite and its eventual excretion. This natural variation in metabolism contributes to the differences observed in clearance times among individuals with similar usage patterns.
Body Composition
Body composition is another factor because THC-COOH is stored in adipose tissue, meaning it binds to fat cells. Individuals with a higher percentage of body fat typically retain the metabolite for longer periods than those with lower body fat percentages. As the body slowly breaks down these fat stores, the stored metabolites are released back into the bloodstream, prolonging the time they are available for detection in urine.
Cartridge Potency
The potency of the vape cartridge used also influences the clearance timeline. Higher concentration oils, which are common in many carts, introduce a greater amount of THC per session. This high dosage results in more THC-COOH production, contributing to the larger metabolite reservoir that must be cleared from the system. Consequently, using an ultra-high potency cartridge can contribute to a longer clearance time compared to using a lower-potency product.