Clinical TrialHealthy VolunteersLSDLSDPlaceboNot yet recruiting

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

This randomised, quadruple-masked, crossover trial (n=24) will assess the pharmacokinetics, safety and subjective effects of DDH-LSD, a novel LSD-like lysergamide, compared with oral LSD and placebo in healthy adult volunteers aged 18–65, with primary aims to determine an effective DDH-LSD dose and to compare duration of action and elimination half-life. The study has two parts: Substudy 1 is an open-label dose‑escalation in healthy participants to identify a DDH-LSD dose that produces clear but tolerable psychoactive effects. Substudy 2 is a randomised, double‑blind, placebo‑controlled crossover in which each participant receives single oral administrations of the selected DDH-LSD dose, 0.1 mg LSD, and placebo on separate supervised study days; each session lasts approximately 13 hours with monitoring of pharmacokinetics, subjective effects, autonomic/physiological responses and safety parameters to provide first‑in‑human characterisation of DDH-LSD.

Target Enrollment
24 participants
Study Type
Phase NA interventional
Design
Randomized, quadruple Blind

Detailed Description

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.

Study Arms & Interventions

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.

Interventions

  • 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.

Interventions

  • LSD

Placebo

inactive

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

Interventions

  • Placebo

Participants

Ages
18 – 65
Sexes
Male & Female

Inclusion Criteria

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

Exclusion Criteria

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

Study Details

  • Status
    Not yet recruiting
  • Phase
    Phase NA
  • Type
    interventional
  • Design
    Randomizedquadruple Blind
  • Target Enrollment24 participants
  • Timeline
    Start: 2026-01-01
    End: 2028-07-01
  • Compounds
    LSDLSDPlacebo
  • Topic
    Healthy Volunteers

Study Team

Sponsors & Collaborators

Locations

University Hospital Basel — Basel, Switzerland

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