THC’s psychoactive effects typically last 2 to 6 hours when smoked or vaped, and up to 12 hours when eaten as an edible. The exact timeline depends heavily on how you consumed it, how much you took, and how often you use cannabis. Beyond the main high, some residual effects like brain fog and fatigue can linger into the next day.
Duration by Consumption Method
The way THC enters your bloodstream changes everything about the timeline. Inhaled cannabis (smoking or vaping) hits fastest and fades fastest. You’ll feel initial effects within 1 to 2 minutes, with the full peak arriving within about 30 minutes. The high generally lasts up to 6 hours, though the strongest effects fade well before that, usually within 2 to 3 hours for most people.
Sublingual products like tinctures and oils placed under the tongue fall in the middle. THC absorbs through the thin tissue under your tongue and enters the bloodstream within 5 to 10 minutes, peaks around 30 to 45 minutes, and wears off within 1 to 2 hours. This makes sublingual the shortest-lasting method overall.
Edibles take the longest to kick in and last the longest. When you swallow THC, it has to pass through your digestive system and liver before reaching your brain. That means 30 minutes to 2 hours before you feel anything, with full effects not peaking until about 4 hours in. The total high can last up to 12 hours, and some residual effects can persist for up to 24 hours. This delayed onset is why people sometimes take a second dose too early, thinking the first one didn’t work, and end up far more intoxicated than they intended.
Why It Lasts Longer for Some People
THC is highly fat-soluble, meaning it dissolves into and gets stored in your body’s fat tissue. People with higher body fat percentages tend to accumulate more THC in their fat cells, where it can remain for weeks. One study found THC still detectable in human fat biopsies 28 days after the last cannabis exposure. This stored THC doesn’t keep you high, but it does get slowly released back into the bloodstream over time, which can extend the tail end of effects and contribute to that foggy feeling the next day.
Exercise can actually trigger some of this stored THC to re-enter your bloodstream. Research published in Drug and Alcohol Dependence found that exercise-induced increases in blood THC levels correlated with body mass index, meaning people with more body fat released more stored THC during physical activity. The amounts released are small, but it’s worth knowing if you’re wondering why you feel slightly off during a workout the day after using cannabis.
Tolerance also plays a major role. If you use cannabis regularly, your brain’s receptors adapt and the same dose produces a shorter, less intense high compared to what an occasional user would experience. Conversely, if you rarely use cannabis, a single session can produce effects that feel stronger and last longer than what a regular user would report.
The “Weed Hangover” the Next Day
Even after the high itself fades, some people experience residual symptoms the following day. Commonly reported next-day effects include fatigue, lethargy, brain fog, dry mouth, dry eyes, headaches, and mild nausea. Research from 2019 confirmed that cannabis use can lead to measurable daytime fatigue the next day, and an earlier study found significant after-effects including irritability.
Not everyone gets a weed hangover. Whether you do depends on the dose, the THC concentration, how you consumed it, and your individual tolerance. Higher doses and edibles are more likely to produce next-day symptoms simply because THC stays active in your system longer. If you still have high levels of THC in your blood the morning after, you may actually still feel somewhat high rather than just hungover.
How Long Impairment Actually Lasts
Feeling sober and being fully unimpaired are not the same thing. The subjective high fades before your reaction time, coordination, and judgment fully return to normal. This distinction matters most for driving.
The largest study on cannabis and driving performance, conducted by researchers at UC San Diego, found that frequent cannabis users showed no driving impairment after at least 48 hours of abstinence. That two-day window is a useful benchmark. While the active high from smoking may feel like it’s gone after 3 or 4 hours, subtle cognitive effects can persist much longer, particularly with edibles or high doses. THC itself is only detectable in blood for a few hours after use, but its metabolites and their effects on coordination linger well beyond that window.
Quick Reference by Method
- Smoking or vaping: Effects start within minutes, peak at 30 minutes, last up to 6 hours
- Sublingual (tinctures/oils): Effects start within 5 to 10 minutes, peak at 30 to 45 minutes, last 1 to 2 hours
- Edibles and capsules: Effects start within 30 minutes to 2 hours, peak around 4 hours, last up to 12 hours with residual effects up to 24 hours
The plasma half-life of THC itself is roughly 1.5 to 2 hours, meaning the amount of active THC in your blood drops by half every couple of hours. But because THC gets pulled into fat tissue and released slowly, the full clearance process takes much longer than simple half-life math would suggest. For practical purposes, plan on being affected for the full duration listed for your consumption method, and allow at least 48 hours before doing anything that requires sharp reflexes or complex decision-making.