NCT07309471

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

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 24 (estimated)
• Sponsor: University Hospital, Basel, Switzerland · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

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.

Detailed description

LSD is a classical serotonergic psychedelic that produces profound alterations in perception and consciousness, primarily through 5-HT2A receptor agonism. Numerous LSD analogs have emerged in recent years, some functioning as prodrugs of LSD, while others show distinct pharmacological characteristics. DDH-LSD is a newly synthesized lysergamide with LSD-like receptor activity but faster metabolism in vitro, suggesting a shorter elimination half-life and potentially briefer psychedelic effects. This study consists of two parts. Substudy 1 is an open-label dose-escalation trial in which healthy participants receive increasing doses of DDH-LSD to identify a dose that produces clear but tolerable psychoactive effects. Substudy 2 is a randomized, double-blind, placebo-controlled cross-over study comparing the selected DDH-LSD dose with LSD and placebo. Each participant completes multiple supervised study days with comprehensive assessment of subjective effects, physiological responses, and pharmacokinetics. The goal is to provide first-in-human data on DDH-LSD, characterize its effect profile, and evaluate how its duration of action compares with LSD.

Conditions

• LSD Reaction

Interventions

Type	Name	Description
DRUG	DDH-LSD	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.
DRUG	LSD	Single oral dose of 0.1 mg LSD. Participants are monitored for 13 hours for pharmacokinetics, subjective effects, autonomic responses, and safety parameters.
DRUG	Placebo	Single oral administration of placebo. Participants are monitored for 13 hours under identical conditions to control for expectancy and procedural effects.

Timeline

• Start date: 2026-03-06
• Primary completion: 2028-07-01
• Completion: 2028-07-01
• First posted: 2025-12-30
• Last updated: 2026-03-10

Locations

1 site across 1 country: Switzerland