LSD ReactionDDH-LSDNCT07309471
Pharmacokinetics of Didehydro-LSD (DDH-LSD) Compared With LSD
A study testing DDH-LSD and LSD in people with LSD Reaction, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- LSD Reaction
- What is being tested?
- DDH-LSD and LSD
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 24 participants
- Where
- 1 siteSwitzerland
- Study dates
- 6 Mar 2026to Jul 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
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- 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
Who cannot join
- 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
Show all 10Show fewer
- 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)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Mélusine Humbert-Droz contact
Switzerland1 site, 1 recruiting
- Recruiting
University Hospital Basel
Basel, 4031
Mélusine Humbert-Droz, +41 61 32 84819, melusine.humbert-droz@usb.ch
Matthias Liechti, Prof. MD, +41 61 32 86868, matthias.liechti@usb.ch
About this study
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.
Read the 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
- Being tested
- DDH-LSD, LSD, Placebo
- Keywords
- DDH-LSD, LSD, Psychedelics, Psychoactive substances, Pharmacokinetics, Pharmacodynamics, Healthy volunteers, 5-HT2A agonist
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DDH-LSDDrug
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.
LSDDrug
Single oral dose of 0.1 mg LSD. Participants are monitored for 13 hours for pharmacokinetics, subjective effects, autonomic responses, and safety parameters.
PlaceboDrug
Single oral administration of placebo. Participants are monitored for 13 hours under identical conditions to control for expectancy and procedural effects.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: 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. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Determine effective DDH-LSD dose
Identify the dose of DDH-LSD that produces clear psychoactive effects.
Measured: 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.
Measured: During each 13-hour study session.
Secondary outcomes (11)
Pharmacokinetics of DDH-LSD
Measure plasma concentration over time
Measured: During each 13-hour study session
Subjective effects: Visual Analog Scales (VAS)
Assess subjective alterations in consciousness using 100 mm horizontal lines (0 = "not at all", 100 = "extremely"). Multiple items (e.g., "any drug effect", "good drug effect", "high", "anxiety") are administered repeatedly during sessions to capture intensity and time course of drug effects.
Measured: During each 13-hour study session
Subjective effects: Adjective Mood Rating Scale (AMRS / EWL60S)
A 60-item Likert scale assessing six dimensions of mood (activation, positive mood, extraversion, introversion, inactivation, emotional excitability). Scores range from 0-100 per subscale, with higher values indicating greater intensity of the dimension.
Measured: Following each 13-hour study session
Subjective effects: 5-Dimensions of Altered States of Consciousness (5D-ASC)
A 94-item questionnaire assessing altered consciousness, perception, mood, and derealization/depersonalization. Scores 0-100 per subscale, with higher values indicating stronger alteration of consciousness.
Measured: Following each 13-hour study session
Subjective effects: Spiritual Realm Questionnaire (SRQ)
A 65-item visual rating scale assessing spiritual and psychedelic experiences across four dimensions (spirituality, human condition, personal problem solving, worldview/beliefs). Scores 0-100 per subscale, higher values indicate stronger experience.
Measured: Following each 13-hour study session
Subjective effects: States of Consciousness Questionnaire (SCQ / MEQ)
A 100-item questionnaire with a 43-item Mystical Experience Questionnaire (MEQ) embedded. Scores 0-100% per domain, with higher percentages reflecting stronger mystical-type experiences.
Measured: Following each 13-hour study session
Effect on heart rate (HR)
Measured: During each 13-hour study session
Effect on blood pressure
Measured: During each 13-hour study session
Effect on body temperature
Measured: During each 13-hour study session
Subjective effects: Scale of Positive and Negative Experience (SPANE)
A 12-item questionnaire measuring positive and negative affect. Subscales range 0-24, with higher scores indicating greater positive or negative affect; the overall balance score reflects general well-being.
Measured: Before each 13-hour study session
Subjective effects: Psychological Insight Questionnaire (PIQ)
A 14-item questionnaire assessing insight into emotions, behavior, beliefs, or relationships. Items rated 0-5 (0 = "not at all", 5 = "extremely"), higher scores indicate greater perceived psychological insight.
Measured: Following each 13-hour study session
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Dec 2025
- Study start6 Mar 2026
- Primary completionJul 2028 (estimated)
- Study completionJul 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for LSD ReactionStudies of the same condition, open and under way.
- More trials run by University Hospital, Basel, SwitzerlandThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- 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.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Basel, Switzerland
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Matthias Liechti, Prof.MD, Study chair, University Hospital of Basel
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07309471
- Sponsor's protocol ID
- 2023-01737;am23Liechti3
- Other IDs
- 2023
- Acronym
- DDH-LSD
- Status last verified
- Mar 2026
- First submitted
- 15 Dec 2025
- Last updated
- 10 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pharmacokinetics of Didehydro-LSD (DDH-LSD) Compared With LSD
- ClinicalTrials.gov ID
- NCT07309471
- Acronym / sponsor ID
- DDH-LSD / 2023-01737;am23Liechti3
- Conditions
- LSD Reaction
- Keywords
- DDH-LSD, LSD, Psychedelics, Psychoactive substances, Pharmacokinetics, Pharmacodynamics, Healthy volunteers, 5-HT2A agonist
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- University Hospital, Basel, SwitzerlandUniversity, hospital or other
- Study start
- 6 Mar 2026 (actual)
- Primary completion
- Jul 2028 (estimated)
- Study completion
- Jul 2028 (estimated)
- First posted
- 30 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| DDH-LSD | Experimental | Drug: DDH-LSDParticipants 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. |
| LSD | Active comparator | Drug: LSDParticipants receive a single 0.1 mg dose of LSD. The session lasts approximately 13 hours with monitoring of subjective, physiological, and pharmacokinetic effects. |
| Placebo | Placebo comparator | Drug: PlaceboParticipants receive a placebo dose. The session lasts approximately 13 hours with monitoring of the same parameters to control for expectancy and procedural effects. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- 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
Key exclusion criteria (10 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| DDH-LSDSingle 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 | DDH-LSD |
| LSDSingle oral dose of 0.1 mg LSD. Participants are monitored for 13 hours for pharmacokinetics, subjective effects, autonomic responses, and safety parameters. | Drug | LSD |
| PlaceboSingle oral administration of placebo. Participants are monitored for 13 hours under identical conditions to control for expectancy and procedural effects. | Drug | Placebo |
Primary outcome
Determine effective DDH-LSD dose
Time frame: During each 13-hour study session.
Identify the dose of DDH-LSD that produces clear psychoactive effects.
Compare duration of action and elimination half-life
Time frame: During each 13-hour study session.
Compare DDH-LSD with LSD and placebo regarding elimination half-life and duration of subjective effects.
11 secondary outcomes
Pharmacokinetics of DDH-LSD
Time frame: During each 13-hour study session
Subjective effects: Visual Analog Scales (VAS)
Time frame: During each 13-hour study session
Subjective effects: Adjective Mood Rating Scale (AMRS / EWL60S)
Time frame: Following each 13-hour study session
Subjective effects: 5-Dimensions of Altered States of Consciousness (5D-ASC)
Time frame: Following each 13-hour study session
Subjective effects: Spiritual Realm Questionnaire (SRQ)
Time frame: Following each 13-hour study session
Subjective effects: States of Consciousness Questionnaire (SCQ / MEQ)
Time frame: Following each 13-hour study session
Effect on heart rate (HR)
Time frame: During each 13-hour study session
Effect on blood pressure
Time frame: During each 13-hour study session
Effect on body temperature
Time frame: During each 13-hour study session
Subjective effects: Scale of Positive and Negative Experience (SPANE)
Time frame: Before each 13-hour study session
Subjective effects: Psychological Insight Questionnaire (PIQ)
Time frame: Following each 13-hour study session
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Mar 2026.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Mélusine Humbert-Droz contact
Matthias Liechti, Prof.MD study chair
University Hospital of Basel
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing DDH-LSD and LSD in people with LSD Reaction, run by University Hospital, Basel, Switzerland at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Matthias Liechti, Prof. MD (+41 61 328 68 68, matthias.liechti@usb.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Determine effective DDH-LSD dose (time frame: During each 13-hour study session.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Mar 2026.