How Long Does Ketamine Stay in Your System?


Ketamine use is on the rise. According to a 2023 government report, nearly 300,000 adults in the UK used ketamine in the past year, marking the highest recorded figure to date.

Despite its growing prevalence, many of us still have misunderstandings about how long ketamine remains in the body and the risks that come with misusing it.

In this help guide, we’ll break down how long ketamine can be detected through different testing methods, the factors that influence its stay in your system and how the short- and long-term effects of use and withdrawal can manifest.

ketamine-text-on-paper

What is Ketamine, and how does the body process it?

Ketamine is a dissociative anaesthetic with properties that can alter perception and mood. Ketamine was originally developed for medical use, particularly for pain relief and anaesthesia during surgery. More recently, ketamine has crept into popular use for its recreational effects and its use for altering and potentially improving mental health. For every user, using the drug carries serious risks, including ketamine addiction and dependence.

Ketamine is rapidly absorbed into the bloodstream and then pumped around the body. It mostly affects your central nervous system by blocking neurotransmitters known as NMDA receptors. This disrupts the natural connection between neurons in the body. The liver then breaks down ketamine into active metabolites, like norketamine, which are eventually passed through your urine.

Although the initial effect of ketamine will wear off within hours, traces of ketamine and its metabolites will linger in the body for several days, depending on a range of physiological factors.

How long does ketamine remain in my system?

If you have ketamine in your system and you’re wondering how long it will take to clear, it’s important to note that it will be traceable in different ways and will depend on the type of test you take. Ketamine metabolites will remain in your body long after its psychoactive effects wear off. Here is a general guide for how long ketamine can be detected:

  • Blood: Up to 24 hours
  • Saliva: Up to 48 hours
  • Urine: Up to 14 days (though more commonly 2–5 days for occasional users)
  • Hair: Up to 90 days

Detection windows are approximate and subject to varying factors.

Which factors affect the duration of ketamine detection?

A host of variables influence how long ketamine can be traced in your system. No two bodies are exactly the same, and personal factors are key in how quickly your body processes and eliminates the substance.

Weight, age and metabolism
People with a faster metabolism, younger age and lower body fat percentage often process ketamine more quickly. Those with slower metabolisms or higher body mass may retain traces of the drug for longer.
Dose and frequency of ketamine used
A one-time, low dose of ketamine will clear from your system more rapidly than frequent or high-dose use. Regular users often build up the drug in their system, meaning it can take longer for their body to eliminate it fully.
Your kidney and liver function
The liver breaks down ketamine and the kidneys help excrete it. If either organ is compromised or isn’t functioning optimally, your body may take longer to clear the drug. These compromises may be related to illness, age, or long-term substance use.
Whether ketamine is taken with other substances
Mixing ketamine with alcohol, other drugs, or medications can impact how it’s metabolised. Other substances may either slow down or complicate the body’s ability to eliminate ketamine, making detection times less predictable.

What are ketamine’s effects and how long do they last?

Ketamine has an average half-life of 2 to 3 hours, meaning that within this time, the concentration of the drug in the bloodstream reduces by half. As the levels drop, users may begin to feel a noticeable “comedown,” the uncomfortable sensations felt as the drug wears off.

In medical terms, a substance is typically considered eliminated from the body after around 4 to 5 half-lives. Based on ketamine’s half-life, this means most of the drug is likely to be cleared from an adult’s system within 10 to 12 hours. However, this doesn’t mean it becomes undetectable straight away, as some drug testing methods can still identify residual traces depending on the type of test used.

Let’s look more closely at ketamine’s short-term effects, its long-term risks and what to expect if you’re coming off the drug.

Ketamine’s short-term effects

The immediate short-term effects after taking ketamine include:

  • Distorted perceptions: feelings of detachment from your body or surroundings (dissociation)
  • Visual and auditory hallucinations: seeing or hearing things that aren’t there
  • Slurred speech and confusion: difficulty thinking clearly or forming sentences
  • Reduced coordination: stumbling or loss of balance, especially at higher doses
  • Numbness or tingling: reduced physical sensation across the body
  • ‘K-hole’ experiences: an intense state of dissociation where you may feel immobilised or out-of-body

These effects generally begin within minutes and wear off after 1–2 hours, but confusion or fatigue may persist for longer.

Ketamine’s long-term effects

Regular ketamine use can result in several physical and psychological consequences. These may include:

  • Bladder damage: This can include ketamine-induced cystitis, causing bladder pain and frequent urination.
  • Memory issues: You may start to find new difficulties retaining information or concentrating.
  • Mental health problems: Long-term effects can increase the risk of depression, anxiety, or emotional blunting.
  • Tolerance build-up: A person will need more ketamine to get the same effect over time, building a dangerous wall of tolerance.
  • Reduced cognitive function: You may start to feel that your brain processes things more slowly or has problem-solving difficulties.
  • Relationship and work disruption: There will likely be major detriments to your personal life as ketamine use takes priority over daily responsibilities.

Long-term use will make quitting harder and increase the risk of dependency, spiralling into a worsening drug addiction.

Ketamine-bottle

Withdrawal symptoms from ketamine

While withdrawal may not be as physically intense as with other substances, psychological ketamine symptoms can still be serious. These may include:

  • Strong cravings: persistent urges to use the drug again
  • Low mood or depression: emotional numbness or sadness when not using
  • Anxiety and restlessness: a sense of inner unease or irritability
  • Sleep issues: insomnia or disturbed sleep patterns
  • Fatigue or low motivation: feeling mentally and physically drained
  • Difficulty concentrating: trouble focusing or making decisions

Withdrawal symptoms can last from a few days to months, depending on the length of the ketamine addiction and the severity of use. Getting support from professionals can reduce the risk of relapse and make the withdrawal period more manageable.

Deep urges felt in withdrawal can become too much to bear alone, making it integral to reach out to someone who can help before addiction worsens.

Where can I get help with addiction recovery?

If you’re concerned about ketamine use, whether that’s your own or someone else’s, know that support is available. You may have started to see the ominous signs of ketamine addiction forming and recognise early that help is needed. That’s what we’re here for.

At UKAT Banbury Lodge, we offer specialist rehab programmes tailored to your needs. We specialise in medical detox, implementing expert-led therapy and long-term aftercare to support lasting recovery. Whether this is your first time seeking help or you’re returning after a setback, our team is here to guide you every step of the way, with care and compassion.

Recovery starts with a single decision. Contact UKAT today and take that step toward a healthier future, free from the grip of addiction.

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