Low-Dose Cannabis Oils Did Not Make Healthy Adults Sleepy or Change Their Sleep | Research

The takeaway

In a placebo-controlled crossover trial of 20 healthy novice cannabis users, low-dose THC:CBD oil formulations (1:1 and 1:16 ratios) did not cause significant daytime sleepiness or alter night-time sleep compared to placebo.

People considering cannabis for sleep, clinicians advising on cannabinoid sleep products, sleep researchers.

Low-dose THC:CBD oils produced no more sleepiness than placebo in healthy adults

What the researchers found

Subjective sleepiness increased from 40 to 265 minutes post-dosing across all conditions (including placebo), but neither the 1:1 THC:CBD nor the 1:16 THC:CBD oil produced greater sleepiness than placebo. Night-time sleep measures (total sleep time, sleep-onset latency, awakenings) measured via actigraphy and sleep diaries during 7-day washout periods showed no significant differences between treatment and placebo conditions.

Why it matters

Many people use cannabinoids for sleep, but this RCT found no sedative effect from low-dose formulations in healthy adults. This challenges the assumption that any cannabis product will improve sleep and highlights that dose, formulation, and patient population matter.

The numbers in context

N=20; mean sleepiness increase of 1.9 points (SE 0.25) from 40 to 265 min post-dosing across all conditions; 1 mL standardized oil doses; 7-day washout periods; no significant between-group differences for sleepiness or any night-time sleep measure.

How the study worked

Double-blind, randomized, placebo-controlled crossover design with 20 healthy adult novice cannabis users. Participants received 1 mL oral oil containing THC:CBD at 1:1 or 1:16 ratios or placebo over five weekly in-lab visits. Daytime sleepiness measured by Karolinska Sleepiness Scale at 40, 135, and 265 minutes post-dosing. Night-time sleep measured by wrist actigraphy and sleep diaries.

What this study cannot tell us

Very small sample (N=20). Only tested low doses in healthy novice users, which may not represent typical medical cannabis patients or experienced users. Single-dose administration does not capture chronic use effects. Actigraphy has limitations compared to polysomnography.

How to read the evidence

Preliminary: Well-designed crossover RCT but very small sample (N=20) in healthy volunteers, limiting clinical generalizability.

When this study was published

Published in 2025.

The bigger picture

The sleep-cannabis relationship is more complex than commonly assumed. While higher-dose THC has shown sedative properties in some studies, this trial suggests that low-dose cannabinoid formulations may not meaningfully affect sleep in healthy users, which has implications for product marketing and clinical guidance.

Questions still open

Would higher doses produce sedative effects? Do experienced cannabis users respond differently to these formulations? Would results differ in people with insomnia or other sleep disorders?

Common questions

Does this mean cannabis does not help with sleep?

Not necessarily. This study tested low doses in healthy adults who did not have sleep problems. Higher doses, different formulations, or testing in people with insomnia might yield different results. The findings suggest that not all cannabis products will automatically improve sleep.

What is a THC:CBD ratio?

The ratio describes the relative amounts of THC and CBD in a product. A 1:1 ratio has equal amounts, while a 1:16 ratio has much more CBD than THC. Different ratios may produce different effects, with higher CBD ratios generally associated with fewer psychoactive effects.

Read the original research

Same-Day Sedative and Night-Time Sleep Effects Following Combined Cannabinoid Formulations: A Randomised-Controlled Trial.

Clinical drug investigation, 45(7), 417-429

View on PubMed ↗Publisher’s paper ↗

Citation

Narayan, Andrea J; Manning, Brooke; Aitken, Blair; Downey, Luke A; Hayley, Amie C. (2025). Same-Day Sedative and Night-Time Sleep Effects Following Combined Cannabinoid Formulations: A Randomised-Controlled Trial.. Clinical drug investigation, 45(7), 417-429. https://doi.org/10.1007/s40261-025-01455-6