Systematic review of CBD doses and effects in 927 adults across 25 studies

A systematic review of 25 human CBD studies found the most consistent evidence for anxiety, social anxiety disorder, and psychotic disorders, with generally mild side effects but wide variation in dosing.

Larsen, Christian et al.·Journal of clinical medicine research·2020·Moderate EvidenceSystematic Review
RTHC-02672Systematic ReviewModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Systematic Review
Evidence
Moderate Evidence
Sample
N=927

What This Study Found

Across 25 studies (927 patients), CBD showed anxiolytic effects with acute administration and therapeutic effects for social anxiety disorder, psychotic disorder, and substance use disorders. Doses and routes of administration varied widely. Side effects were generally mild, though study quality was often limited.

Key Numbers

25 studies; 927 patients (538 men, 389 women); from 5 countries; doses varied significantly across studies.

How They Did This

Systematic review of 25 human studies (22 controlled trials, 3 observational) from PubMed, Embase, and Cochrane, published 2000-2019, examining CBD efficacy and safety in adults.

Why This Research Matters

CBD products are sold at wildly different doses with little guidance. This review provides the first systematic look at what doses have actually been tested in humans and what conditions show the most evidence.

The Bigger Picture

The huge variation in CBD dosing across studies reflects how early this field still is. Without standardized dosing protocols, comparing results across studies remains difficult, which is one reason consumer CBD products vary so widely.

What This Study Doesn't Tell Us

Substantial heterogeneity in doses, formulations, and routes of administration; many studies had high risk of bias; limited sample sizes in individual studies.

Questions This Raises

  • ?What are the optimal CBD doses for specific conditions?
  • ?Can standardized dosing protocols be developed for clinical use?

Trust & Context

Key Stat:
25 studies, 927 patients: best evidence for anxiety and psychosis
Evidence Grade:
Moderate: systematic methodology across 25 studies, but limited by heterogeneous designs and substantial bias risk.
Study Age:
Published 2020.
Original Title:
Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.
Published In:
Journal of clinical medicine research, 12(3), 129-141 (2020)
Database ID:
RTHC-02672

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Analyzes all available research on a topic using a structured method.

What do these levels mean? →

Frequently Asked Questions

What conditions does CBD work best for?

The strongest evidence was for acute anxiety relief, social anxiety disorder, psychotic disorders, and substance use disorders. Evidence for other conditions was more limited.

Is CBD safe?

Across 25 studies, side effects were generally mild. However, doses and formulations varied widely, and long-term safety data are limited.

Read More on RethinkTHC

Cite This Study

RTHC-02672·https://rethinkthc.com/research/RTHC-02672

APA

Larsen, Christian; Shahinas, Jorida. (2020). Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.. Journal of clinical medicine research, 12(3), 129-141. https://doi.org/10.14740/jocmr4090

MLA

Larsen, Christian, et al. "Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.." Journal of clinical medicine research, 2020. https://doi.org/10.14740/jocmr4090

RethinkTHC

RethinkTHC Research Database. "Dosage, Efficacy and Safety of Cannabidiol Administration in..." RTHC-02672. Retrieved from https://rethinkthc.com/research/larsen-2020-dosage-efficacy-and-safety

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.