A THC high from smoking or vaping typically lasts 1 to 3 hours, while edibles can keep you feeling effects for 6 to 8 hours or longer. The exact duration depends on how you consume it, how much you take, and your individual biology.
Smoking and Vaping: 1 to 3 Hours
When you inhale THC through smoking or vaping, effects begin within 2 to 10 minutes. You’ll usually notice a head rush or a shift in how things look, sound, or feel. The high reaches its peak intensity around 20 to 45 minutes in, when THC concentration in your blood is at its highest. From there, effects gradually taper off over the next couple of hours as your body breaks down the THC.
Most people feel essentially back to normal within 3 hours of their last hit. That said, higher doses push that timeline out. In a study of infrequent users who took a 15 mg oral dose (roughly comparable to a strong session), participants still rated themselves as feeling “stoned” at the 8-hour mark.
Edibles: 4 to 8 Hours or More
Edibles follow a completely different timeline because THC has to pass through your digestive system and liver before reaching your brain. Onset takes anywhere from 30 minutes to 2 hours, which is why people sometimes make the mistake of eating a second dose before the first one kicks in.
Your liver converts THC into a related compound that crosses into the brain more easily and produces effects similar to THC itself. With edibles, this compound builds up in parallel with THC rather than fading quickly, which is a big part of why the high feels stronger and lasts so much longer. Brain levels of THC peak between 1 and 2.5 hours after eating and don’t drop to minimal levels until many hours later.
Total duration runs 6 to 8 hours for most people, sometimes longer depending on the dose and your metabolism. The peak tends to hit around the 2-hour mark, with a long, slow comedown after that.
Tinctures: Somewhere in Between
Sublingual tinctures (drops held under the tongue) split the difference between inhaling and eating. Because THC absorbs through the thin tissue under your tongue directly into your bloodstream, it bypasses the digestive system. Effects typically begin within 15 to 30 minutes. The high doesn’t last quite as long as edibles but still provides several hours of noticeable effects. If you swallow the tincture instead of holding it under your tongue, it behaves more like an edible, with a slower onset and longer duration.
How Dose Changes the Timeline
Higher doses don’t just make the high more intense. They make it last longer. A study published in Psychopharmacology gave infrequent cannabis users either 7.5 mg or 15 mg of THC orally. The lower dose produced mild, intermediate effects. The higher dose impaired memory most severely at the 2-hour mark, with some cognitive effects still measurable at 4 hours. Subjectively, participants on the 15 mg dose reported feeling significantly stoned at 2, 4, 6, and even 8 hours after taking it. At the lower dose, effects blended closer to placebo and resolved much sooner.
This is especially relevant for edibles, where standard doses range from 5 to 10 mg per serving. A 5 mg dose might produce a mild, manageable experience lasting 4 hours. A 25 mg dose in the same person could mean an uncomfortably intense high stretching well past 8 hours.
CBD Can Make THC Last Longer
Many cannabis products contain both THC and CBD, and a common assumption is that CBD mellows out the high. Research from Johns Hopkins tells a different story for edibles. When participants ate brownies containing 20 mg of THC alongside a high dose of CBD, the peak THC levels in their blood were nearly twice as high as when they ate brownies with the same amount of THC alone. The active byproduct produced by the liver was 10 times higher in the CBD combination.
The practical result: participants reported stronger overall drug effects, more unpleasant side effects, greater difficulty performing routine tasks, and a larger increase in heart rate. CBD appears to slow the liver’s ability to break down THC, effectively amplifying and extending the experience. This matters if you’re choosing products labeled as having a balanced THC-to-CBD ratio and expecting a gentler ride.
Why Duration Varies Between People
Two people can take the same dose and have noticeably different experiences. Several factors explain this. Tolerance is the most obvious: regular users metabolize THC more efficiently and experience shorter, less intense highs from equivalent doses. Body composition plays a role too, since THC is fat-soluble and distributes differently depending on how much body fat you carry.
Genetics may be the most underappreciated factor. About one in four people carry a gene variant that causes their liver enzymes to break down THC less effectively than average. For these individuals, the same dose produces a stronger high that lasts longer. Research from the Medical University of South Carolina suggests this genetic difference helps explain why some people have unexpectedly negative experiences with cannabis, even at modest doses.
How Long Impairment Actually Lasts
The subjective feeling of being high and the actual window of cognitive impairment don’t always match up perfectly. You might feel sober before your reaction time and memory have fully recovered, or you might feel lingering effects after your brain function has returned to baseline.
A review in Frontiers in Psychiatry examined this question across multiple studies and found that measurable cognitive impairment from inhaled THC resolves within 4 hours or less, even in people on different dosing schedules. After 4 hours of recovery, no study found a difference between THC groups and placebo on any cognitive test. For edibles, the window is longer. Canadian medical guidelines recommend waiting 3 to 4 hours after inhaling cannabis, and 6 to 8 hours after eating it, before driving or doing anything that requires sharp focus and coordination. If you felt any euphoria, the recommendation extends to at least 8 hours regardless of method.
It’s also worth noting that THC remains detectable in your body long after the high and any impairment have passed. Urine tests can pick up THC metabolites for days in occasional users and weeks in daily users. A positive drug test does not mean you’re still impaired, but it does mean the substance is still being cleared from your system.