Comparing acute effects of R‑MDMA and S‑MDMA in healthy adults

Comparative Acute Effects of R-MDMA and S-MDMA in Healthy Participants

This will test whether a single dose of R‑MDMA or S‑MDMA causes different short-term effects in healthy adults compared with placebo.

Quick facts

• Phase: Phase 1
• Study type: Interventional
• Enrollment: 24 (estimated)
• Ages: 18 Years to 65 Years
• Sex: All
• Sponsor: University Hospital, Basel, Switzerland (Academic / other)
• Locations: 1 site (Basel, Canton of Basel-City)
• Trial ID: NCT06905652 on ClinicalTrials.gov

What this trial studies

This phase 1 interventional trial will compare the acute effects of a single dose of R‑MDMA, a single dose of S‑MDMA (doses adjusted to be equivalent), and placebo in healthy adults. Participants aged 18–65 who meet inclusion criteria will receive one of the interventions under medical supervision and will be monitored for subjective, physiological, and hormonal responses. The study builds on preclinical data suggesting differing neurotransmitter profiles for the enantiomers and a prior human comparison that used unequal doses. Results will characterize safety, tolerability, and short-term prosocial or stimulant effects to inform future therapeutic development.

Who should consider this trial

Good fit: Healthy adults aged 18–65 who speak German, have BMI 18–34.9, no major medical or psychiatric disorders, agree to abstain from illicit drugs during the study, and use effective birth control are ideal candidates.

Not a fit: People with current or past major psychiatric disorders, relevant medical or cardiovascular conditions, recent illicit substance use, or those unable to comply with protocol language and safety requirements are unlikely to benefit.

Why it matters

Potential benefit: If successful, the results could identify an MDMA enantiomer with fewer adverse effects and stronger prosocial effects, guiding safer development of MDMA-based therapies.

How similar studies have performed: Preclinical studies suggest different actions of R‑ and S‑MDMA and a recent human comparison found generally similar effects, though that study did not use equivalent enantiomer doses.

Eligibility criteria

Inclusion Criteria:

1. Age between 18 and 65 years
2. Good 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. Willing not to operate heavy machinery within 48 h after administration of a study substance (including driving a car)
7. Willing to use effective birth-control throughout study participation.
8. Body mass index 18 - 34.9 kg/m2

Exclusion Criteria:

1. Relevant chronic or acute medical condition
2. Current or previous major psychiatric disorder (e.g. bipolar disorder, schizophrenia), current depression or anxiety disorder
3. Psychotic disorder or bipolar disorder in first-degree relatives
4. Hypertension (SBP\>140/90 mmHg) or hypotension (SBP\<85 mmHg)
5. Illicit substance use (not including cannabis) more than 20 times or any time within the previous month.
6. Pregnancy or current breastfeeding
7. Participation in another clinical trial (currently or within the last 30 days)
8. Use of medications that may interfere with the effects of the study medication
9. Tobacco smoking (\>10 cigarettes/day).
10. Excessive consumption of alcoholic beverages (\>15 drinks/week)

Where this trial is running

Basel, Canton of Basel-City

• University Hospital Basel — Basel, Canton of Basel-City, Switzerland (Recruiting)

Study contacts

• Principal investigator: Matthias E Liechti, Prof. Dr. MD — University Hospital, Basel, Switzerland
• Study coordinator: Matthias E Liechti, Prof. Dr. MD

Conditions Healthy