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Study of Oral THC and D-limonene Effects

This study is looking at how orally given d-limonene and delta-9-tetrahydrocannabinol (THC), and their combination, affect healthy adults. Researchers want to see if d-limonene, a common flavor in plants like cannabis, changes the effects of THC when taken by mouth, similar to how it might when inhaled. You could be eligible if you are between 21 and 55 years old, in good general health, and have used cannabis before. The study will measure how you feel after taking these substances using a Visual Analog Scale (a way to rate your feelings) up to 8 hours after dosing. The study is currently recruiting participants, aiming for 20 people to complete the full protocol.

Study design
This is an interventional study with an unclear status, planning to enroll 65 participants. It will compare the effects of d-limonene, delta-9-THC, and a placebo.
What's involved
You would attend 6 outpatient drug administration sessions. You will also have a physical examination, medical history review, vital signs taken, and urine and blood tests during screening.
Compensation
Not stated in the trial record.
Follow-up
Your subjective drug effects will be assessed up to 8 hours after dosing.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06378957

Behavioral Pharmacology of Orally Administered THC and D-limonene

Recruiting
PHASE1Ages 21–55InterventionalBasic science
Johns Hopkins University
~65 participants
Updated 2026-05-28 on ClinicalTrials.gov
What's tested:D-LimoneneDelta-9-THCPlacebo

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Subjective Drug Effect as assessed by Visual Analog Scale
Measured over 8 hours after dosing

Conditions

Subjective Drug Effects
THC
D-limonene

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Healthy Volunteers

NCT06378957

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • Johns Hopkins Behavioral Pharmacology Research Unit

    Baltimore, Marylandno site contact published

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • Austin Zamarripa, PhD · PRINCIPAL_INVESTIGATOR · Johns Hopkins School of Medicine

Who to contact

Austin Zamarripa, PhD
[email protected]
410-550-6969
Email the study team

Opens a ready-to-send draft in your own email app — review before sending.

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Eligibility criteria

Inclusion

Have provided written informed consent
Be between the ages of 21 and 55
Be in good general health based on a physical examination, medical history, vital signs, and screening urine and blood tests
Test negative for drugs of abuse other than cannabis, including breath alcohol at the screening visit and at clinic admission
Not be pregnant or nursing (if female). All females must have a negative serum pregnancy test at the screening visit and a negative urine pregnancy test at clinic admission.
Have a body mass index (BMI) in the range of 18 to 36 kg/m2
Blood pressure at Screening Visit does not exceed a systolic blood pressure (SBP) of 150 mmHg or a diastolic blood pressure (DBP) of 90 mmHg
Have no allergies to any of the ingredients used to prepare (cellulose, THC, d-limonene).
Report having used a high THC cannabis product in the past 3 years and having experienced anxiety after consuming cannabis at least once in lifetime.

Exclusion

Non-medical use of psychoactive drugs other than, nicotine, alcohol, or caffeine 3 month prior to the Screening Visit;
History of or current evidence of significant medical (e.g. seizure disorder) or psychiatric illness (e.g. psychosis) judged by the investigator to put the participant at greater risk of experiencing an adverse event due to exposure or completion of other study procedures.
Use of an over the counter (OTC), systemic or topical drug(s), herbal supplement(s), or vitamin(s) within 14 days of experimental sessions; which, in the opinion of the investigator or sponsor, will interfere with the study result or the safety of the subject.
Use of a prescription medication (with the exception of birth control prescriptions) within 14 days of experimental sessions; which, in the opinion of the investigator or sponsor, will interfere with the study result or the safety of the subject.
Average use of cannabis more than 2 times per week in the prior 3 months.
History of clinically significant cardiac arrhythmias or vasospastic disease (e.g., Prinzmetal's angina).
Enrolled in another clinical trial or have received any drug as part of a research study within 30 days prior to dosing.
Individuals with anemia or who have donated blood in the prior 30 days

What this trial measures

  • Subjective Drug Effect as assessed by Visual Analog Scale8 hours after dosing

    Subjective drug effect will be measured on a 100 point visual analog scale (VAS) where 0 = no drug effect and 100 = strongest drug effect imaginable