Withdrawal timelines vary widely depending on the substance, but most acute withdrawal episodes resolve within one to four weeks. Some substances clear in days, others take weeks, and lingering symptoms can persist for months. The single biggest factor determining how quickly withdrawal starts and how long it lasts is the substance’s half-life: how fast your body eliminates it. Short-acting drugs trigger withdrawal sooner but resolve faster, while long-acting drugs produce a slower, more drawn-out process.
Why Half-Life Determines the Timeline
Your body adapts to the steady presence of a substance by adjusting its own chemistry. When levels drop, your nervous system is left in an unbalanced state, and that imbalance is what you feel as withdrawal. Drugs with short half-lives are washed out of your system quickly, so withdrawal hits fast and hard. Drugs with long half-lives leave gradually, so withdrawal builds more slowly and tends to be less intense but longer-lasting.
This is why heroin withdrawal starts within hours while methadone withdrawal can take days to appear. It’s also why short-acting anti-anxiety medications are harder to stop than longer-acting versions of the same class. The principle applies across nearly every substance category.
Alcohol
Alcohol withdrawal symptoms typically begin within 8 hours of the last drink, though they can occasionally appear days later. Symptoms peak between 24 and 72 hours and the acute phase generally lasts 5 to 7 days. Early symptoms include anxiety, tremors, sweating, nausea, and insomnia.
The most dangerous complication is delirium tremens, a severe form of withdrawal that can involve confusion, hallucinations, seizures, and dangerously high blood pressure. Alcohol is one of the few substances where withdrawal itself can be life-threatening, which is why heavy, long-term drinkers are often advised to detox under medical supervision rather than stopping abruptly.
Even after the acute phase passes, sleep disruption, mood swings, and fatigue can linger for months.
Opioids
The timeline for opioid withdrawal depends on whether you were using a fast-acting or slow-acting opioid. For short-acting opioids like heroin or oxycodone, symptoms typically start 6 to 12 hours after the last dose, peak around days 2 to 3, and resolve within 5 to 7 days. The experience is often described as an intense flu: muscle aches, sweating, nausea, diarrhea, and restlessness.
For longer-acting opioids like methadone, withdrawal symptoms don’t usually appear until 1 to 3 days after the last dose. The symptoms tend to be less severe but can stretch out for 2 to 3 weeks. Opioid withdrawal is deeply uncomfortable but, unlike alcohol or benzodiazepine withdrawal, it is rarely life-threatening on its own.
Benzodiazepines
Benzodiazepine withdrawal is one of the most unpredictable timelines. Acute withdrawal generally begins within a few days of stopping and lasts anywhere from 5 to 28 days, though some people experience symptoms for several months. Rebound anxiety, the very symptom these medications were prescribed for, often returns intensely during withdrawal, along with insomnia, irritability, and difficulty concentrating.
Like alcohol, benzodiazepine withdrawal carries a risk of seizures, which is why doctors almost always recommend a gradual taper rather than stopping cold turkey. The taper itself can extend the total timeline to 3 to 5 weeks or longer, but it significantly reduces the severity and danger of symptoms.
Nicotine
Nicotine withdrawal begins 4 to 24 hours after your last cigarette, vape, or other nicotine product. Symptoms peak on the second or third day and then gradually fade over 3 to 4 weeks. The most common symptoms are cravings, irritability, anxiety, trouble concentrating, insomnia, and increased appetite. Less common symptoms include headaches, nausea, dizziness, and constipation.
The physical withdrawal is relatively short, but the psychological pull of nicotine can persist much longer. Cravings triggered by habits and environments associated with smoking may come in waves for months, even after the chemical withdrawal has fully resolved.
Antidepressants
Stopping antidepressants, particularly SSRIs and SNRIs, can cause what’s formally called discontinuation syndrome. Symptoms typically emerge within days to weeks of stopping or significantly lowering a dose, usually once 90% or more of the drug has left your system. Common symptoms include dizziness, nausea, flu-like feelings, irritability, and the distinctive “brain zaps,” a sensation resembling a brief electric shock or shiver inside your head.
Most discontinuation symptoms resolve within a few weeks. If symptoms persist beyond a month and are getting worse rather than better, that may signal a return of the underlying depression rather than ongoing withdrawal. A slow, gradual taper is the standard approach to minimize these effects.
Stimulants
Withdrawal from stimulants like cocaine, amphetamines, or methamphetamine typically lasts 1 to 2 weeks. The pattern is almost the opposite of other withdrawal syndromes: instead of agitation and anxiety, stimulant withdrawal is dominated by fatigue, depression, increased sleep, and intense cravings. The “crash” phase in the first few days can involve sleeping for unusually long stretches and feeling profoundly low.
Cannabis
Cannabis withdrawal is real but relatively brief, with the acute phase lasting about 5 days. Symptoms include irritability, headaches, disrupted sleep, and unusually vivid dreams. It’s generally mild compared to other substances, though heavy, daily users may find the sleep disruption and irritability more significant than expected.
Post-Acute Withdrawal Syndrome
For many people, acute withdrawal is only the first chapter. Post-acute withdrawal syndrome (PAWS) describes a set of lingering symptoms that can persist for months to as long as two years after stopping a substance. The most common symptoms are mood swings, sleep problems, fatigue, cravings, and difficulty concentrating.
PAWS looks slightly different depending on the substance. After alcohol, it tends to involve anxiety, depression, and persistent cravings. After opioids, mood swings, insomnia, and low motivation are typical. After benzodiazepines, cognitive fog, muscle pain, and tremors may continue. Stimulant PAWS often centers on depression, fatigue, and poor impulse control.
Not everyone experiences PAWS. Some people feel fine after the acute phase, while others feel better for a month or two before symptoms reappear. The intensity varies significantly from person to person, and chronic, heavy use increases the likelihood and duration of these lingering effects. The brain changes caused by long-term substance use, particularly in the circuits that regulate mood and stress, take time to recalibrate even after the substance is fully out of your system.
Factors That Change Your Timeline
Two people stopping the same substance can have very different experiences. Several factors push the timeline shorter or longer:
- Duration of use. The longer you’ve used a substance, the more your brain has adapted to it, and the longer it takes to readjust. Someone who drank heavily for a decade will generally have a harder withdrawal than someone who drank heavily for six months.
- Dose. Higher doses create deeper physical dependence. Tapering from a high dose takes longer and requires more gradual steps.
- Type of substance. As outlined above, each substance has its own characteristic timeline based on how it affects the brain and how quickly it’s eliminated.
- Individual metabolism. Age, liver function, body composition, and genetics all affect how quickly you process and eliminate a substance, which in turn affects when withdrawal begins and how long it lasts.
- Co-occurring mental health conditions. Depression, anxiety, or other mental health conditions can overlap with and intensify withdrawal symptoms, making it harder to distinguish what’s withdrawal and what’s an underlying condition resurfacing.
In clinical settings, providers use standardized scoring tools to track withdrawal severity over time. For opioids, an 11-item scale rates symptoms like restlessness, sweating, and pupil size on a numerical score, with anything above 36 considered severe withdrawal. Similar tools exist for alcohol. These scores help clinicians adjust treatment in real time rather than relying on a fixed calendar.