How Long Does LSD Stay in Your System?

3 min read · 6 sections

LSD tablet on red background

LSD can be detected in a urine test for 2-4 days after last use, in a blood test for 6-12 hours after last use, and in a hair test for up to 90 days. Factors that can affect these tests include how much LSD the person took prior to the test, their age, their health, and their weight.

The onset and duration of effects of LSD depend on dose taken and the method of use, but most “trips” last between 9-12 hours. Effects include visual hallucinations, distorted perception of time, mood swings, and impaired judgment.

Risks of use include “bad trips,” flashbacks, injuries, and adverse interactions with medications such as antidepressants or lithium.

What Is LSD?

Lysergic acid diethylamide, commonly referred to as LSD or acid, is a highly potent hallucinogenic drug. It is made from lysergic acid, which is derived from a fungus that grows on rye and other grains.1

LSD is typically sold in the form of small tablets, capsules, or liquids. A solution of liquid LSD is commonly added to blotter paper and divided into decorated squares.1

LSD is almost always taken orally, but it may also be used via other routes, such as being dropped into the eye. Over the years, various street names have been used for the drug, including blotter acid, dots, Mellow Yellow, Window Pane, and Yellow Sunshine. 2,3,4

How Is It Metabolized?

LSD is completely absorbed in the digestive tract. The liver quickly breaks it down into 2-oxy-LSD and 2-oxo-3-hydroxy LSD—both inactive byproducts of LSD metabolism (metabolites). Other metabolites include LAE, nor-LSD, 13- and 14-hydroxy-LSD, lysergic acid ethyl-2-hydroxyethylamide, trioxylated LSD, and di-hydroxy-LSD.4

The half-life of LSD is 3.6 hours, which means it takes about that amount of time for half of the dose to be cleared from the bloodstream.4

How Long Do the Effects Last?

The onset of LSD effects, and the duration of those effects, depend on the dose and how the person takes the drug. In experimental settings:

  • A 100-250 microgram dose taken by mouth will produce effects within 30-45 minutes, with peak effects occurring between 1 hour and 2.5 hours and lasting 9-12 hours.
  • A 100-250 microgram dose taken by intramuscular injection will produce effects within 15-20 minutes, with peak effects occurring within 1 hour and lasting 9-10 hours.
  • A 40-180 microgram dose taken by intravenous injection will produce effects within 3-5 minutes, with peak effects occurring within 1 hour and lasting 9-10 hours.
  • A 20-60 microgram intraspinal dose will produce effects in less than an hour, with peak effects occurring within an hour and lasting 9-10 hours.4

While on LSD, a person may experience the following effects:1,2,3

  • Dilated pupils.
  • Dry mouth.
  • Loss of appetite.
  • Increased body temperature.
  • Sweating.
  • Elevated heart rate and blood pressure.
  • Tremors.
  • Impaired judgment.
  • Inability to sleep.
  • Visual hallucinations.
  • Synesthesia (“hearing” colors or “seeing” sounds).
  • Changes in perception of time (seeming to pass more slowly than normal).
  • Distorted sense of the shape and size of objects, movements, colors, sound, touch, and body image.
  • Delusions.
  • Rapid mood swings.
  • Panic.

How Long Does LSD Stay in Your Body?

LSD is not commonly tested for on many standard drug tests. That being said, it is possible to specifically test for LSD use via urine, blood, and hair samples.

In many LSD-positive urine tests, the metabolite 2-oxo-3-hydroxy-LSD may be found at higher levels than LSD itself. It can be detected for a longer period of time than LSD as well.4

What Are the Risks of Use?

There are both physical and psychological risks to using LSD.

Impaired judgment on an LSD trip presents one of the greatest threats to the physical safety of the user. Poor decision-making or strange behaviors while on the drug can lead to physical injury or law enforcement intervention.2,3

A negative experience on LSD, also known as a “bad trip,” can be very unpleasant. Users may have terrifying thoughts or feelings; fear of losing control, insanity or death; or severe despair. Other reactions include depressed mood or mental instability in the days after the experience.4

Users can also experience flashbacks of their LSD experience that can occur suddenly in the range of days to more than a year after last use. Flashbacks can happen without warning and include re-experiencing certain aspects of the trip.2

For some users, flashbacks can recur and interfere with their daily lives. In some cases, the perceptual disturbances experienced during a flashback—such as seeing trails on objects—may persist for significant periods of time despite not having used the drug. This condition is known as hallucinogen persisting perceptual disorder.2

In addition, research has investigated a link between LSD use and the onset of schizophrenia. Researchers have suggested that taking LSD may hasten the onset of schizophrenia in vulnerable individuals, and that people who have a genetic predisposition to developing schizophrenia may be more likely to experience a greater psychotic reaction to the drug.6

Finally, LSD can interact negatively with medications you may be taking, such as antidepressants. Case studies have documented flashbacks in former LSD users who began taking selective serotonin reuptake inhibitors (SSRIs). However, other studies have found that regularly taking SSRIs or monoamine oxidase inhibitors (MAOIs) can reduce the effects of LSD. On the other hand, lithium and tricyclic antidepressants may increase LSD’s effects, and concurrent lithium use in particular can lead to dangerous reactions, including temporary comatose states.4,7

Is LSD Addictive?

The National Institute on Drug Abuse (NIDA) explains that LSD is not addictive because it does not cause uncontrollable urges to repeatedly use the drug. LSD use over time, however, does cause tolerance in frequent users. These users must increase their dose of LSD in order to recreate the same level of high that they previously experienced. Due to the unpredictability of the symptoms and side effects caused by LSD use, this is an unsafe habit.2

LSD use does not result in physical dependence and therefore physical withdrawal symptoms do not occur. Frequent users do not experience cravings to use the drug, though psychological dependence is possible.8

NIDA explains that inpatient and behavioral treatment options can be helpful for individuals who have developed persistent patterns of problematic drug use, which may include LSD. Particularly for individuals struggling with alcohol or other drugs in addition to LSD, participation in a treatment program can be very beneficial.2


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