How Long Does Ketamine Stay in Your System?

Ketamine drugs and plastic straw for smell

The amount of time that a drug remains in your system depends on its half-life, which is the amount of time that it takes your body to process half of the drug into metabolic byproducts. As a general rule, a drug is almost completely eliminated from your system after five half-lives have passed. Ketamine has a short duration of action and a short half-life, meaning that it will be out of your system relatively quickly.

Duration of Effects of Ketamine

The duration of ketamine effects varies somewhat based on the dose and route of administration. Intramuscular injections typically have an onset of effect within approximately four minutes and a duration of action anywhere from 15 to 30 minutes. Intravenous injections typically have an onset of action within 10 to 30 seconds and a duration of action of between 5 to 15 minutes.

The duration of action depends on several factors:

  • Age: Young people metabolize ketamine faster than older people.
  • Dose: Higher doses of ketamine are associated with a longer duration of action.
  • Route of administration: When injected ketamine, ketamine leaves the body much more quickly than when taken orally.
  • The presence of other drugs or alcohol: Other drugs including alcohol can intensify and prolong the effects of ketamine. Therefore, it is important to let your doctor know about any other medications you are taking.
  • Metabolism: Individuals with a faster metabolism will clear the drug faster than others.

Ketamine Half-Life

The half-life of ketamine is typically broken into two phases, the alpha phase, and the beta phase. The alpha phase of ketamine metabolism is approximately 10 to 15 minutes, and the beta phase is approximately 2.5 hours. This means that ketamine will be nearly completely metabolized within approximately 12.5 hours.

Ketamine Screening Detection Times

Although the time that ketamine is metabolically present in someone’s body is typically less than a day, it may be detected for longer time frames. Metabolic byproducts may remain in the system for far longer than ketamine itself. Ketamine drug tests that look for the presence of byproducts may deliver positive results for several days after the latest use.


Ketamine’s metabolic byproducts may be detected in urine for up to 14 days after the latest use. Heavy ketamine use may be detectable for up to 30 days.


Ketamine blood tests are unusual because they require trained professionals who can obtain blood samples. Blood tests are generally able to detect ketamine for approximately 24 hours after the latest use.


Saliva tests are common because they are non-invasive and do not require trained professionals to obtain samples. Ketamine can be detected in saliva for up to 24 hours after the latest use.


After someone uses ketamine it circulates through their bloodstream, reaching every part of the body. Even hair follicles receive blood. If ketamine is present the follicle will absorb some of it into growing hair strands, which will essentially hold on to ketamine in its un-metabolized form for as long as that hair remains on someone’s head. Consequently, ketamine may be identified in hair for up to three months after the last use.

Factors Affecting How Long Ketamine Stays in Your System

There are a number of factors that influence how long ketamine will stay in your system, including:

  • Amount used
  • Frequency of use
  • Method of use
  • Age
  • Overall health
  • Kidney Health

False Positives for Ketamine

False positives for ketamine are very uncommon, but there have been isolated cases of false-positive urine tests for ketamine after the person being tested took the prescription antipsychotic drug quetiapine (brand name Seroquel).

Ketamine is a derivative of the dangerous recreational drug phencyclidine (PCP) and, while PCP use will not deliver a false positive in a ketamine test, ketamine may produce a false positive in a PCP test.

How Ketamine is Broken Down in the Body

After administration, ketamine is rapidly absorbed and distributed throughout the body. Ketamine metabolism is primarily broken down in the liver and excreted in the urine.

Ketamine addiction can be challenging to overcome. If you are struggling with a ketamine use disorder, The Recovery Village Ridgefield can help. Contact one of our experts today to learn how professional rehab can get you on the road to recovery.

Rosenbaum, Steven B; Palacios Jorge L. “Ketamine.” NCBI StatPearls, February 2019. Accessed October 9, 2019.

Food and Drug Administration. “KETALAR (ketamine hydrochloride) injection.” April 2017. Accessed October 9, 2019.

Liu, Chun-Hao; et al. “False positive ketamine urine immunoassay screen result induced by quetiapine: A case report.” Journal of the Formosan Medical Association, September 2017. Accessed October 9, 2019.

Li, Linda; Vlisides, Phillip E. “Ketamine: 50 Years of Modulating the Mind.” Frontiers in Human Neuroscience, November 2016. Accessed October 9, 2019.