How long does lsd last
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Duration of LSD Effects: A Comprehensive Overview
Pharmacokinetics of LSD
Lysergic acid diethylamide (LSD) is a potent psychedelic substance known for its profound effects on consciousness and perception. The pharmacokinetics of LSD, which describe how the drug is absorbed, distributed, metabolized, and excreted in the body, play a crucial role in determining the duration of its effects.
Absorption and Peak Concentration
After oral administration, LSD is rapidly absorbed into the bloodstream. Peak plasma concentrations are typically reached within 1 to 2 hours post-administration1 8. For instance, in a study where participants received doses of 5, 10, and 20 µg of LSD, peak concentrations were observed at approximately 1.1 hours1. Similarly, another study reported maximum blood plasma levels occurring between 1.2 and 2 hours after administration of doses ranging from 50 to 100 µg8.
Elimination Half-Life
The elimination half-life of LSD, which is the time it takes for the plasma concentration of the drug to reduce by half, varies but is generally around 2.7 to 4.3 hours1 2 8. This relatively short half-life indicates that LSD is rapidly cleared from the bloodstream. For example, one study calculated the half-life of LSD to be approximately 175 minutes (about 2.9 hours)2.
Duration of Subjective Effects
Acute Effects
The subjective effects of LSD, which include alterations in mood, perception, and cognition, typically begin within 30 to 90 minutes after ingestion and can last for several hours. The duration of these effects is dose-dependent. Lower doses (e.g., 10 µg) may produce effects that last around 5 hours, while higher doses (e.g., 100-200 µg) can result in effects lasting up to 12 hours or more1 4 5 9.
For instance, a study administering 200 µg of LSD reported pronounced alterations in consciousness lasting approximately 12 hours5. Another study found that the duration of subjective effects increased from 6.7 to 11 hours with doses ranging from 25 to 200 µg9.
Influence of Antagonists
The duration of LSD's effects can be significantly shortened by the administration of serotonin receptor antagonists. For example, ketanserin, a 5-HT2A receptor antagonist, was shown to reduce the duration of LSD's subjective effects from 8.5 hours to 3.5 hours when administered one hour after LSD4. This highlights the role of serotonin receptors in mediating the psychedelic effects of LSD.
Conclusion
In summary, the effects of LSD typically begin within 30 to 90 minutes after ingestion, peak at around 1 to 2 hours, and can last anywhere from 5 to 12 hours depending on the dose. The elimination half-life of LSD is approximately 2.7 to 4.3 hours, indicating rapid clearance from the bloodstream. The duration of LSD's effects can be modulated by serotonin receptor antagonists, which can significantly shorten the experience. Understanding these pharmacokinetic and pharmacodynamic properties is essential for both recreational users and those considering LSD for therapeutic purposes.
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Most relevant research papers on this topic
Pharmacokinetics and Pharmacodynamics of Lysergic Acid Diethylamide Microdoses in Healthy Participants
Low doses of LSD can cause psychotropic effects, with the threshold dose being 10 g, and concentrations increase dose-proportionally with a half-life of 3 hours.
RCT
Rigorous JournalPersistence of lysergic acid diethylamide in the plasma of human subjects
LSD-25 has a half-life of 175 minutes in human plasma, with large quantities present during peak effect and a relatively short half-life in the brain.
Non-RCT
Highly CitedThe paradoxical psychological effects of lysergic acid diethylamide (LSD)
LSD elicits psychosis-like symptoms acutely but improves psychological wellbeing in the mid to long term, due to increased cognitive flexibility and emotional lability during intoxication.
RCT
Very Rigorous JournalHighly CitedKetanserin Reverses the Acute Response to LSD in a Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Participants
Ketanserin effectively shortens and attenuates the LSD experience in humans, making it a potential option for research and LSD-assisted therapy.
RCTVery Rigorous JournalAcute Effects of Lysergic Acid Diethylamide in Healthy Subjects
LSD can be used safely in a controlled clinical setting for hallucinogenic effects and empathogenic mood effects, with no severe acute adverse effects observed.
RCTVery Rigorous JournalHighly CitedRepeated low doses of LSD in healthy adults: A placebo‐controlled, dose–response study
Repeated low doses of LSD are safe but produce negligible changes in mood or cognition in healthy volunteers.
RCTRigorous JournalLSD-assisted psychotherapy for anxiety associated with a life-threatening disease: A qualitative study of acute and sustained subjective effects
LSD-assisted psychotherapy is safe and can generate lasting benefits for patients with anxiety associated with life-threatening diseases.
Observational StudyVery Rigorous JournalHighly CitedSafety, tolerability, pharmacokinetics, and subjective effects of 50, 75, and 100 µg LSD in healthy participants within a novel intervention paradigm: A proof-of-concept study
50, 75, and 100 g LSD are tolerable with favourable safety profiles in healthy adults, causing mild adverse events and mystical-type subjective experiences.
RCTVery Rigorous JournalAcute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects
LSD has dose-dependent effects, with a ceiling effect for good effects at 100 g, and ego dissolution and anxiety increasing further at doses above 100 g.
RCTVery Rigorous JournalHighly CitedLong-lasting alterations in behavior and brain neurochemistry following continuous low-level LSD administration
Continuous low-level LSD administration leads to persisting neurotoxic effects, including decreased social distance and decreased binding in limbic regions, even after drug administration is stopped.
Non-RCT
Animal Study