- The peak psychotropic effects of LSD occur around 2.5 hours after ingestion and last approximately four hours.
- Low doses of LSD, especially the 10 µg dose, provide significant subjective effects compared to placebo, while doses below this threshold do not.
- LSD exhibits dose-proportional pharmacokinetics, with a relatively short elimination half-life of around three hours, indicating it does not accumulate with repeated doses.
Study Background
This publication is the third in a series of studies on the pharmacokinetics and pharmacodynamics of very low doses of LSD. The researchers conducted a placebo-controlled and double-blind study involving 23 healthy participants, discovering that doses of 10 µg LSD produce psychotropic effects, further heightened at 20 µg. The most noticeable effects peaked at around 2.5 hours and generally dissipated by the five-hour mark.
Research Context
The authors note the rising interest in utilizing LSD for therapeutic purposes alongside the recreational trend of microdosing—administering very low doses of the substance to enhance cognitive abilities and mood. However, they emphasize a significant lack of existing data on the effects of such microdoses, particularly the specific amounts that do not result in subjective experiences. Previous studies examining the pharmacokinetics of low doses have been hampered by inadequate data and limitations in analytical sensitivity.
Study Design and Methodology
To address these gaps, the researchers structured a study assessing the pharmacokinetics and effects of 5, 10, and 20 µg doses of LSD in a group of 23 subjects while employing a sophisticated analytical approach. The doses were precisely created from an LSD tartrate solution, and both blood samples and subjective ratings were collected over a defined timeframe to explore the pharmacokinetic and pharmacodynamic relationships.
Participant Criteria
The study targeted healthy individuals aged 18 to 40 with suitable body mass indexes and prior hallucinogen experiences. Strict exclusion criteria were in place, dismissing anyone with a history of drug addiction, psychiatric issues, significant health problems, or excessive alcohol and tobacco habits.
Results Overview
The results indicated that plasma LSD concentrations were accurately quantified in various participant groups for all doses. The elimination half-lives noted were 2.5 hours for the 5 µg dose, 2.7 hours for the 10 µg dose, and 2.9 hours for the 20 µg dose. Emerging from this data, it was confirmed that increasing LSD doses led to proportionate rises in plasma concentrations.
Subjective Effects Findings
Regarding subjective experiences, the findings revealed that a 5 µg dose of LSD did not yield significant differences from the placebo. However, at 10 µg, participants reported marked increases in ratings related to feelings of being “under the influence” and experiencing “good drug effects.” Conversely, the administration of 20 µg led to enhanced evaluations across both positive and negative subjective experiences, including “bad drug effects.” The authors detailed that effects from the 10 µg dose started about 1.1 hours post-ingestion, peaked at 2.5 hours, and typically lasted until approximately 5.1 hours after dosage.
Conclusions and Implications
In summary, the researchers underscored the significance of their findings, marking a pivotal moment in understanding the pharmacokinetics associated with LSD microdoses. They acknowledged that their study illuminates the pharmacological profile of very low doses of LSD, reinforcing that doses under 10 µg may be classified as sub-perceptual. Ultimately, they posited that this research could inform future studies exploring the use of LSD in therapeutic contexts for both healthy individuals and those facing various health challenges.
Read the full paper summary on Blossom.
