Pharmacokinetics of Didehydro-LSD (DDH-LSD) Compared With LSD

NCT07309471 | Recruiting DMC

• 1 other identifier: 2023-01737;am23Liechti3
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

This study investigates DDH-LSD, a novel LSD-like compound expected to have a shorter duration of action than LSD. In healthy volunteers, pharmacokinetics, safety, and subjective effects, will be assessed and compare with LSD in a controlled cross-over study.

Conditions

LSD Reaction

Keywords

DDH-LSD; LSD; Psychedelics; Psychoactive substances; Pharmacokinetics; Pharmacodynamics; Healthy volunteers; 5-HT2A agonist

Outcome Measures

Primary Outcomes (2)

• Determine effective DDH-LSD dose

  Identify the dose of DDH-LSD that produces clear psychoactive effects.

  During each 13-hour study session.

• Compare duration of action and elimination half-life

  Compare DDH-LSD with LSD and placebo regarding elimination half-life and duration of subjective effects.

  During each 13-hour study session.

Secondary Outcomes (11)

• Pharmacokinetics of DDH-LSD

  During each 13-hour study session

• Subjective effects: Visual Analog Scales (VAS)

  During each 13-hour study session

• Subjective effects: Adjective Mood Rating Scale (AMRS / EWL60S)

  Following each 13-hour study session

• Subjective effects: 5-Dimensions of Altered States of Consciousness (5D-ASC)

  Following each 13-hour study session

• Subjective effects: Spiritual Realm Questionnaire (SRQ)

  Following each 13-hour study session

Study Arms (3)

DDH-LSD

EXPERIMENTAL

Participants receive a single dose of DDH-LSD at the dose determined in Substudy 1. The session lasts approximately 13 hours with monitoring of subjective, physiological, and pharmacokinetic effects.

Drug: DDH-LSD

LSD

ACTIVE COMPARATOR

Participants receive a single 0.1 mg dose of LSD. The session lasts approximately 13 hours with monitoring of subjective, physiological, and pharmacokinetic effects.

Drug: LSD

Placebo

PLACEBO COMPARATOR

Participants receive a placebo dose. The session lasts approximately 13 hours with monitoring of the same parameters to control for expectancy and procedural effects.

Drug: Placebo

Interventions

DDH-LSD DRUG

Single oral dose of DDH-LSD at the dose determined in Substudy 1. Participants are monitored for 13 hours for pharmacokinetics, subjective effects, autonomic responses, and safety parameters.

DDH-LSD

LSD DRUG

Single oral dose of 0.1 mg LSD. Participants are monitored for 13 hours for pharmacokinetics, subjective effects, autonomic responses, and safety parameters.

LSD

Placebo DRUG

Single oral administration of placebo. Participants are monitored for 13 hours under identical conditions to control for expectancy and procedural effects.

Placebo

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age between 25 and 65 years old
• Sufficient understanding of the German language
• Understanding of procedures and risks associated with the study
• Willing to adhere to the protocol and signing of the consent form
• Willing to refrain from the consumption of illicit psychoactive substances during the study
• Abstaining from xanthine-based liquids from the evenings prior to the study sessions and during the sessions
• Willing not to operate heavy machinery within 48 h of substance administration
• Willing to use effective contraceptive measures throughout study participation
• Body mass index between 18-32 kg/m2

You may not qualify if:

• Chronic or acute medical condition
• Current or previous major psychiatric disorder
• Psychotic disorder or bipolar disorder in first-degree relatives
• Hypertension (SBP\>140/90 mmHg) or hypotension (SBP\<85 mmHg)
• Use of hallucinogenic substances (not including cannabis) more than 20 times or any time within the previous two months
• Pregnancy or currently breastfeeding
• Participation in another clinical trial (currently or within the last 30 days)
• Use of medication that may interfere with the effects of the study medication
• Tobacco smoking (\>10 cigarettes/day)
• Consumption of alcoholic beverages (\>20 drinks/week)

Sponsors & Collaborators

• University Hospital, Basel, Switzerland: lead

Study Sites (1)

University Hospital Basel

Basel, 4031, Switzerland

RECRUITING

MeSH Terms

Interventions

Lysergic Acid Diethylamide

Intervention Hierarchy (Ancestors)

Lysergic Acid; Ergolines; Ergot Alkaloids; Alkaloids; Heterocyclic Compounds; Heterocyclic Compounds, 4 or More Rings; Heterocyclic Compounds, Fused-Ring

Study Officials

• Matthias Liechti, Prof.MD

  University Hospital of Basel

  STUDY CHAIR

Central Study Contacts

Matthias Liechti, Prof. MD

CONTACT

+41 61 328 68 68; matthias.liechti@usb.ch

Mélusine Humbert-Droz

CONTACT

melusine.humbert-droz@usb.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Part 1: Open lable, within-subject, dose-escalation study of DDH-LSD to identify a dose producing measurable psychoactive effects. Part 2: randomized, double-blind, placebo-controlled, balanced cross-over study comparing DDH-LSD with LSD and placebo, allowing direct assessment of pharmacokinetics, duration of action, and subjective effects. Each participant completes multiple supervised study sessions separated by washout periods.

Study Record Dates

• First Submitted: December 15, 2025
• First Posted: December 30, 2025
• Study Start: March 6, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): July 1, 2028
• Last Updated: March 10, 2026

Record last verified: 2026-03

Locations

CH (1)