How Long Does Ketamine Stay in Your System?

Ketamine stays in your system for about a week on average, but it can be detected on some drug tests for longer.

Ketamine begins affecting a person only minutes after use, with a high typically lasting 30 minutes to an hour. 

It can be detected in urine for about a week and in hair for about three months. Blood testing is rare, but it has a slightly longer detection window than urine at 9 to 14 days.

Ketamine Timeline

Ketamine is a dissociative anesthetic that is used as a “club drug” and sometimes to facilitate sexual assault and being roofied. On the street, powdered ketamine is typically packaged in 100 mg to 200 mg doses, with liquid ketamine also available in similar doses. 

The effect of ketamine is rapid, taking only a few minutes for a user to begin feeling its effects. A ketamine high typically lasts for about 30 to 60 minutes. This differentiates it from similar drugs, which may affect a person for hours after use.

In rare cases, a user may experience what is called hallucinogen persisting perception disorder (HPPD) several weeks after use. When this occurs, a user may experience some of the negative hallucinogenic effects of ketamine that occurred with their initial use. 

How Long Can Ketamine Use Be Detected?

Ketamine use can be detected in the body days or even weeks after use if the appropriate tests are used. Typically, urine testing works best to detect use within about a week, and hair testing works best for detection of use over longer periods.

Time Since Use	Effect
Initial dose	The drug will take effect within minutes, distorting a person’s perceptions and making them feel disconnected from their body. The person will generally feel sedated and immobile. They will experience partial or total amnesia of events that occur after taking the drug.
10–20 minutes	Heart rate and blood pressure typically increase and then gradually decrease over this period.
30–60 minutes	Effects will gradually strengthen and then fade away, with a user regaining more of their faculties until their high fades completely.
6–9  days	Typically, ketamine can be detected in a person’s urine for about this length of time, with properly targeted testing. Use is possible to detect in urine for longer but with less reliability.
90 days	This is typically considered the maximum length of time ketamine (and most drug use) can be detected in a person’s hair.

Testing for Ketamine

There are various ways to test for ketamine, although urine tests are the most commonly used.

Hair Testing

Testing for drug use through hair is one of the most accurate ways to test use over time and to detect drug use that occurred weeks or more in the past. 

Research has suggested a cutoff window of 0.5 ng/mg is best for detecting repeated ketamine use. 

Drug testing in this way is only possible once the patient’s hair has grown out, but it can provide accurate results for multiple months after drug cessation. 

Urine Testing

It is possible to test for ketamine use through urine, with the right testing methodology able to detect use for about six days after use with reasonable reliability. Notably, this doesn’t guarantee detection. 

While urine tests can be used to detect illicit drug use, they can also be helpful for detecting if a person may have been victimized using the drug. Urine testing is typically how people are tested for ketamine use unless information about a person’s history of drug use is the goal, in which case hair testing is used.

Blood Testing

Blood testing for ketamine use is rare but still available. Urine testing is generally preferred as it is less invasive. 

Blood testing can have a longer detection period, however, with at least one company advertising an accurate detection window of about 7 to 14 days. Chronic drug use potentially extends that detection window.

Testing Methodology	Approximate Detection Window
Hair	90 days
Urine	6–9 days
Blood	7–14 days

Influential Factors on How Long Ketamine Stays in Your System

A number of factors can influence how long a person’s drug use can be detected. These include the following:

• Dose taken
• Frequency of use
• Individual’s body type
• Test used
  

In general, the more drugs a person takes over a shorter period, the easier it is to detect some trace of their drug use. 

Notably, ketamine is not a drug that is often tested for in a typical drug test. Most drug testing looks for commonly abused drugs, including marijuana, opioids, and alcohol. For a test to have any chance of detecting ketamine use, it must be designed for that purpose. 

References

Cut-Off Proposal for the Detection of Ketamine in Hair. (March 2015). Forensic Science International.

Evaluation of Ketamine Abuse Using Hair Analysis: Concentration Trends in a Singapore Population. (July 2005). Journal of Analytical Toxicology.

Ketamine. (April 2020). U.S. Drug Enforcement Agency.

Hallucinogen-Persisting Perception Disorder. (October 2012). Therapeutic Advances in Psychopharmacology.

The Abuse Liability of Ketamine: A Scoping Review of Preclinical and Clinical Studies. (July 2022). Journal of Psychiatric Research.

A Fast Screening Procedure for Ketamine and Metabolites in Urine Samples with Tandem Mass Spectrometry. (April 2010). Journal of Analytical Toxicology.

Ketamine Addiction & Abuse. (February 2021). Confirm Biosciences.

Urinary Excretion Rates of Ketamine and Norketamine Following Therapeutic Ketamine Administration: Method and Detection Window Considerations. (July 2005). Journal of Analytical Toxicology.