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NCT Number: NCT06755346

The Effects of Cannabis on Male Reproductive Functions

The purpose of this study is to understand the direct effects of cannabis on male reproductive functions. The investigators plan to conduct a double-blind, placebo-controlled clinical trial to examine both the chronic and acute effects of cannabis use on male reproductive functions. Specifically, the investigators will examine the dose-dependent effects of acute cannabis use on male reproductive parameters, including sperm counts, motility, morphology, and testosterone levels, as well as sperm epimutations.

Participants [cannabis users will be randomly assigned to 1) non-vaping, 2) placebo (vaping without cannabis), and 2 doses of cannabis, 3) 20 and 4) 40mg of THC in cannabis flower obtained from the NIDA drug supply], and 5) non-cannabis users (naïve control, no cannabis or placebo exposure).

Participants will provide surveys (cannabis use and sexual functioning and satisfaction etc.), peripheral blood, and semen.

Why the study stopped: We terminated the study. Since the FDA did not approve our study, we could not begin it. I have terminated it.
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Key information

Conditions

Male Reproductive Problem Chemically-Induced Disorders Marijuana Abuse Mental Disorders Substance-Related Disorders

Age range

21 year–64 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 1

Primary location

Washington State University

Pullman, Washington, 99164, United States

About this study

The Volcano Vaporizer will be used to expose cannabis or placebo plants.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Regular cannabis users (21~64 years-old men) who have used cannabis at least once a week for at least once a year or who have never used cannabis.
  • Willingness to abstain from using cannabis on the day of the testing session (minimum 5 hours abstinence).

Exclusion criteria

  • Women
  • Adult men, 65 or older, and men under the age of 21
  • Serious psychiatric conditions (e.g. psychosis, bipolar I and panic disorder)
  • Family history of psychosis
  • Chronic medical conditions (e.g., heart disease, diabetes)
  • History of adverse experiences with cannabis (e.g., anxiety and panic attacks)
  • Use of other illicit drugs (not cannabis) in the past 2 months
  • Heavy alcohol use (>4 drinks, >4 times/week)
  • Smoking/nicotine use
  • Infrequent cannabis use (less than once a week for only cannabis users)
  • BMI over 34
  • Current use of corticosteroids and blood thinners

Treatment and study plan

Cannabis plant (THC 20mg)

Drug

Cannabis flower - very High THC (>10%) / Low CBD (<1%)

Other names: marijuana

Cannabis (0%/ THC / 0% CBD)

Drug

THC (0%) / CBD (0%) - Placebo marijuana

Cannabis plant (THC 40mg)

Drug

Cannabis flower - very High THC (>10%) / Low CBD (<1%)

Other names: marijuana

Primary outcomes

  1. Number of participants with treatment-related sperm parameters

    Time frame: 30 minutes

    Sperm counts and motility, as well as DNA fragmentation, will be examined after vaping or no vaping.

  2. Number of participants with treatment-related sperm epimutation

    Time frame: 30 minutes

    Differentially methylated regions in sperm will be analyzed to examine the effects of cannabis exposure.

  3. Number of participants with treatment-related plasma testosterone and THC/THC metabolites

    Time frame: 4 hours

    Plasma testosterone and THC/THC metabolites will be analyzed to examine the effects of cannabis exposure.

Secondary outcomes

  1. Number of participants with treatment-related stress reactivity and food intake

    Time frame: 4 hours

    After the vaping session and semen collection, participants will complete the Acute Stress Test. Plsama cortisol will be analyzed before and after the Acute Stress Test. During sobering (~4 hours), snacks (e.g., fruit snacks, granola bars, chips, chocolate, soda, juice, and water) will be available for participants. Investigators will monitor participants via the window in the adjacent room to monitor and record the snacks/beverages participants choose to consume.

Sponsors and collaborators

Lead sponsor

Kanako Hayashi

Other

Collaborators

  • Washington State University

Registry information

Official study title

The Acute and Chronic Effects of Cannabis on Reproductive Functions in Men

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jan 1, 2025
Registry last updated
Aug 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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