Double blind, randomized controlled trial on CBD and sleep quality

This trial compared the effectiveness of ingested capsules of CBD isolate, CBD with other cannabinoids, and melatonin on sleep quality among people experiencing sleep disturbance. It was published in the Journal of the American Nutrition Association in May 2023.

It was a randomized, parallel design, double-blind controlled study. The authors' definition of 'double blind': "neither the participants nor those who collected the data were aware of the product participants received until the conclusion of the study."

Eligibility requirements: at least 21 years old, reside in the United States, and reported that they were experiencing symptoms of sleep disturbance. Patients were sent a 4 week supply of capsules at the start of the study.

The were divided into 6 arms (groups) according to the capsule formulation:

  1. 15mg CBD + 15mg CBN + 5mg melatonin
  2. 15mg CBD + 15mg CBN
  3. 15mg CBD
  4. 5mg melatonin
  5. 15mg CBD full spectrum + 15mg CBN
  6. 15mg CBD + 15mg CBN + 5mg CBC


1,298 included participants (average age 46.5, 57% women) were instructed to take 1 capsule per day with food before going to bed. They were allowed to take 2 capsules with food before bed if they felt it was necessary. They were not allowed to take more than 2 capsules per day.

The average dose was about 1.4 capsules (21 mg cannabinoids or 7 mg melatonin). This means that they only assessed the effectiveness of a few very specific dosage regimens. We don't know if more CBD would have been more effective.

The study used an 8-item assessment of sleep disturbance that participants were requested to complete at least once a week over the 4 week period. The items measure characteristics of sleep, sleep disturbances and sleep quality using a 5-point Likert scale.

In short, 15 mg to 30 mg CBD intake helped improve sleep quality. Combining CBD with CBC, CBN, or melatonin did NOT improve the results, which showed that 15 mg of CBD is about as effective as 5 mg melatonin. Unfortunately, they did not examine any other dosage levels of CBD, and we know that cannabinoids can affect people very differently. 

Nonetheless, patients take CBD for many other reasons (pain, inflammation, anxiety, cancer, etc.) and knowing that it may also improve sleep quality at the same time is very beneficial - no extra melatonin (or other drug) needed.

Authors' quotes:

Most participants (56% to 75%) across all formulations experienced a clinically important improvement in their sleep quality.

There were no significant differences in effect, however, between 15 mg CBD isolate and formulations containing 15 mg CBD and 15 mg cannabinol (CBN), alone or in combination with 5 mg cannabichromene (CBC).

There were also no significant differences in effect between 15 mg CBD isolate and formulations containing 5 mg melatonin, alone or in combination with 15 mg CBD and 15 mg CBN.


The full text article is here at