How long a high lasts depends entirely on the substance. A cannabis high from smoking typically lasts up to 6 hours, while an edible high can stretch to 12. A cocaine high fades in under an hour, whereas LSD can keep you altered for 6 to 15 hours. Below is a practical breakdown of the most commonly searched substances, what affects the timeline, and how long impairment actually lingers after the high itself fades.
Cannabis: Smoked vs. Edibles
The method of consumption changes the experience dramatically. When you smoke or vape cannabis, effects begin within seconds to a few minutes, peak within about 30 minutes, and last up to 6 hours. Residual effects like brain fog or mild mood changes can linger up to 24 hours after use.
Edibles follow a completely different timeline. Because the cannabis travels through your stomach and liver before reaching your bloodstream, onset takes anywhere from 30 minutes to 2 hours. Full effects may not peak until 4 hours in. The intoxicating effects can last up to 12 hours, with residual effects stretching to 24 hours. This slow onset is why people commonly make the mistake of eating more before the first dose kicks in, then finding themselves far more intoxicated than intended.
The liver also converts THC into a stronger form during digestion, which combines with the THC from the original product. This is why edible highs feel more intense and last so much longer than smoking the same amount of THC.
Alcohol
Alcohol doesn’t produce a “high” in the same sense, but the buzz and intoxication follow a predictable metabolic clock. Your liver clears alcohol at a fixed rate of roughly 0.015 BAC per hour, regardless of how much coffee you drink or how much water you chug. That means if you reach a BAC of 0.08 (the legal driving limit in most U.S. states), it takes about 5 to 6 hours to fully metabolize.
Someone who drinks heavily enough to reach a BAC of 0.20, for instance, could still have impaired judgment at a BAC of 0.08 ten hours later, feel foggy and fatigued at 0.065 eleven hours later, and not reach zero until roughly 13 hours after their last drink. Even at that point, full cognitive recovery takes additional time. The buzz may feel like it’s gone long before impairment actually clears.
Cocaine and Methamphetamine
Cocaine produces one of the shortest highs of any recreational drug. Snorted cocaine typically peaks within 15 to 30 minutes and fades within about 45 minutes to an hour, which is a major reason people tend to redose frequently. Smoked or injected cocaine hits faster but wears off even quicker, sometimes in as little as 10 to 15 minutes.
Methamphetamine produces a similar stimulant high but on a vastly different timeline. Effects can last up to 12 hours depending on the method of use, according to the Centre for Addiction and Mental Health. That prolonged duration contributes to extended periods without sleep, which compound the drug’s psychological effects and make the crash afterward significantly more severe.
LSD and Psilocybin Mushrooms
Psychedelics are at the long end of the spectrum. A single dose of LSD (one “tab”) begins producing effects within 20 to 90 minutes. The trip itself lasts anywhere from 6 to 15 hours, though most experiences fall in the 8 to 12 hour range. After the main trip ends, an “afterglow” period of altered mood, either pleasant or anxious, can persist for another 6 hours. All told, it can take up to 24 hours to feel fully back to baseline.
Psilocybin mushrooms produce a shorter trip, generally lasting 4 to 6 hours with onset in 20 to 40 minutes. The afterglow period is similar, with lingering mood shifts for several hours after the visual and cognitive effects subside. Neither substance allows you to cut the experience short once it begins, which is worth knowing before taking either one.
Caffeine
Caffeine is technically a psychoactive stimulant, and its timeline surprises most people. It takes about 30 minutes to feel the effects (the range is 15 to 45 minutes), but the half-life is 5 to 6 hours. That means if you drink a cup of coffee at 3 p.m., half the caffeine is still active in your system at 8 or 9 p.m. The noticeable alertness and energy boost typically last 3 to 5 hours, but the compound remains in your body much longer than that, which is why afternoon caffeine disrupts sleep even when you feel like it’s worn off.
Why Duration Varies Between People
Two people can take the same substance in the same amount and have noticeably different experiences. Several factors explain this. Your liver does most of the work breaking down drugs through a family of enzymes, and genetic differences mean some people produce more of these enzymes than others. People who metabolize a drug quickly will feel a shorter, sometimes weaker high. Slow metabolizers experience longer, more intense effects from the same dose.
Age plays a significant role. Older adults see a reduction of 30% or more in their liver’s processing capacity because both liver volume and blood flow decrease over time. This means drugs reach higher concentrations and take longer to clear. Very young people are also affected: neonates and young children have underdeveloped enzyme systems and metabolize many substances poorly.
Chronic liver disease or heart failure can further slow drug metabolism, extending both the high and the period of impairment. Other substances in your system matter too. Many drugs either speed up or slow down the same liver enzymes, meaning a combination of substances can produce unpredictable changes in how long each one lasts.
Tolerance Shortens the Perceived High
If you use a substance regularly, your body adapts. This tolerance means you typically need more of the drug to achieve the same effect. For frequent cannabis users, a high that once lasted 4 to 5 hours may feel like it fades in 2 to 3. The drug is still in your system for the same amount of time, but the subjective experience of being high diminishes. This creates a cycle of increasing doses, which raises the risk of adverse effects even though the high itself feels shorter.
How Long Impairment Outlasts the High
One of the most important things to understand is that impairment lasts longer than the high. With cannabis, residual cognitive effects can persist for up to 24 hours after use, well beyond the point where you feel “normal.” Alcohol impairment continues at measurable levels long after the pleasant buzz fades. Even prescription medications that cause drowsiness or dizziness can impair your ability to drive or operate machinery hours after the noticeable effects seem to have cleared.
The core problem is that impaired people cannot accurately judge their own impairment. Studies on driving safety consistently show that people who feel sober enough to drive often are not. If you feel any different from your normal baseline, your reaction time, judgment, and coordination are still affected, regardless of which substance caused it.