Deeper Sleep, Not Just More Sleep

How CBD And Terpenes Are Being Studied To Reshape Our Nights

If you have ever woken up after a “full” night of sleep and still felt foggy, you already know that hours in bed are only part of the story. What really matters is how much of that time your brain spends in the restorative stages of sleep that repair the body, reset the mind, and help you feel genuinely renewed the next day. A new clinical trial is starting to ask a different question about CBD: not “Does it knock you out?” but “Can it gently shift your sleep architecture toward deeper, more restorative stages?”

What did this new study actually test?

A team of researchers in the United States ran a double‑blind, placebo‑controlled, randomized crossover trial in people with chronic insomnia. Instead of giving a single cannabinoid, they used a capsule combining:

• 300 mg purified CBD
• 1 mg each of eight terpenes: linalool, myrcene, phytol, limonene, α‑terpinene, α‑terpineol, α‑pinene, and β‑caryophyllene
• No detectable THC

Participants took one capsule about an hour before bed at least four nights per week, for two separate four‑week periods (one with the CBD–terpene formula, one with a placebo), with a washout in between. Everyone wore a WHOOP wrist sleep‑tracking device, which estimated how much time they spent in:

• Light sleep
• Deep, slow‑wave sleep (SWS)
• REM sleep
• Total sleep time

The primary outcome was not “Did you fall asleep faster?” or “Did you sleep longer?” It was the percentage of total sleep time spent in slow‑wave plus REM sleep, sometimes called “restorative sleep,” because those stages are strongly linked to immune function, tissue repair, and memory.

Key results in plain language

Across the 56 participants who completed the protocol with usable device data, the CBD–terpene formulation produced several notable patterns:

• It increased the percentage of time spent in deep + REM sleep by about 1.3 percentage points on average compared with placebo (95% CI 0.1–2.5%).
• It reduced the percentage of light sleep by about 1.7 percentage points.
• It did not significantly change total sleep time or resting heart rate.
• No serious adverse events were reported, and the regimen was well tolerated across the group.

Those average numbers look modest, but averages hide a lot of individual variation. When the researchers dug deeper, they found:

• Among people who started with a low baseline deep + REM (≤40% of their night), the increase in restorative sleep was larger—about 3.8 percentage points on average, with corresponding drops in light sleep.
• In a small subgroup of day sleepers (shift‑worker‑type patterns), the shift was even bigger: roughly 7 percentage points more deep + REM sleep and 8 percentage points less light sleep, on average.
• For the top responders, that translated to around 40–50 extra minutes of deep/REM sleep per night over the four‑week period, without extending total sleep time.

Subjective questionnaires about sleep quality, ease of falling asleep, sleep depth, and dream vividness all trended in a positive direction, but those changes did not reach statistical significance in this relatively small sample.

What are deep and REM sleep, and why do they matter?

From a science perspective, your night is not one uniform state. It cycles through repeating stages roughly every 90 minutes:

• Light NREM sleep – the “gateway” stage where your brain begins to disconnect from the outside world.
• Slow‑wave sleep (SWS, deep sleep) – marked by large, slow brain waves, growth hormone release, physical repair, and important immune and metabolic activity.
• REM sleep – a more active brain state where most vivid dreaming happens, linked to emotional processing, learning, and memory consolidation.

Together, SWS and REM are often grouped as “restorative sleep” because they support:

• Immune function and tissue regeneration
• Clearance of metabolic waste from the brain
• Energy replenishment and glucose regulation
• Learning, memory, attention, and executive function

In chronic insomnia, people may get enough total minutes of sleep on paper, but their proportion of SWS and REM can be unusually low, leaving them feeling unrefreshed despite a normal‑looking night. The CBD–terpene study is interesting precisely because it focuses on quality and composition of sleep, not just quantity.

How might CBD and terpenes influence sleep stages?

This trial was designed as a clinical test, not a mechanistic lab experiment, so it cannot fully explain how the formula works. But the broader literature gives several plausible pathways:

• CBD interacts with the endocannabinoid system, serotonin receptors, and other signaling pathways that influence arousal, stress responses, and circadian rhythms.
• Preclinical studies show CBD can increase slow‑wave sleep in animals and may modulate sleep in humans, although results from earlier small trials have been mixed.
• Terpenes like linalool and myrcene show sedative or calming properties in animal models and are thought to contribute to the “entourage effect” of aromatic plants, including some cannabis chemotypes.

Putting these together, the authors hypothesize that the specific ratio of CBD plus selected terpenes may gently shift the balance between light and restorative sleep, particularly in people whose baseline sleep architecture is out of balance.

What this means for you

The problem this study addresses is not just “I can’t fall asleep” but “My sleep doesn’t feel restorative, even when I do.” Many people with chronic insomnia complain that they spend much of the night in a light, easily broken state of half‑sleep.

The study suggests:

• CBD by itself is probably not a magic switch for insomnia, but in the right dose and paired with targeted terpenes, it may help some people spend more of the night in restorative stages.
• The benefits seem stronger in people starting with low deep/REM or disrupted timing, which may resemble what shift workers and “tired but wired” insomniacs experience.
• Because total sleep time and heart rate did not change much, the formula appears to be tuning the pattern of sleep, not acting like a heavy sedative.

At the same time, it’s important to recognize the limits: this was one study, with 56 people in the final analysis, and the average effects were modest. We do not yet know the long‑term impact, how it compares directly with standard insomnia therapies, or which individual profiles respond best.

How this fits with CBD products you see online

Real‑world CBD sleep products vary widely in:

• CBD dose (from a few milligrams to several hundred)
• Presence or absence of THC
• Terpene profiles (often not standardized)
• Added ingredients such as melatonin or other botanicals

The research formulation in this trial used CBD only (no THC), a defined set of eight terpenes, and relatively high CBD dosing (300 mg). That is quite different from many over‑the‑counter products that pair low‑dose CBD with melatonin or advertise “full spectrum” oil without quantifying terpenes.

If you are considering trying a CBD‑based sleep product, this study suggests it is worth paying attention to:

• Whether THC is present (this formula had none)
• Whether terpenes are specified and standardized
• How does the dosing compare with what has been studied

And of course, it remains essential to talk with a health professional, especially if you take medications that are metabolized by the same liver enzymes CBD can affect.

What this does not show

To stay grounded and FDA‑aware, it is equally important to be clear about what this trial does not demonstrate:

• It does not show that CBD treats, cures, or prevents insomnia.
• It does not prove that everyone with sleep problems will benefit. In fact, many participants showed little or no change.
• It does not compare CBD–terpene capsules head‑to‑head with prescription hypnotics, CBT‑I (cognitive behavioral therapy for insomnia), or melatonin.

What it does offer is a careful piece of evidence that CBD, when combined thoughtfully with specific terpenes, may help some people with insomnia nudge their sleep toward deeper, more restorative patterns—an idea that fits nicely with a “rest and renewal” theme, but still needs more research before becoming routine care.

---

About the Original Study

Title
Effects of a cannabidiol/terpene formulation on sleep in individuals with insomnia: a double‑blind, placebo‑controlled, randomized, crossover study. pmc.ncbi.nlm.nih

Journal and date
Journal of Clinical Sleep Medicine, 2025; 21(1):69–80. pubmed.ncbi.nlm.nih

Authors

• Michael Wang, PhD – Research scientist at Defined Research Institute, focusing on sleep physiology and cannabinoid‑based formulations. colab
• Marcus Faust – Scientist at Defined Research Institute, involved in clinical trial design and data analysis. colab
• Scott Abbott – Scientist at Defined Research Institute, contributing to cannabinoid formulation research. colab
• Vikrant Patel – Scientist at Defined Research Institute with expertise in human sleep studies. colab
• Eric Chang – Scientist at Defined Research Institute supporting clinical operations and analysis. colab
• John I. Clark, PhD – Professor of Biological Structure and Ophthalmology, University of Washington; biophysicist with experience in imaging and quantitative analysis. pmc.ncbi.nlm.nih
• Nephi Stella, PhD – Professor of Pharmacology and Psychiatry & Behavioral Sciences; Director, UW Center for Cannabis Research, specializing in endocannabinoid signaling and cannabinoid therapeutics. cannabis.uw
• Paul J. Muchowski, PhD – Founder and CEO/CSO of Defined Research Inc.; neuroscientist focused on developing clinically tested cannabinoid‑based products (corresponding investigator for this trial). linkedin

Links to the study

Clinical trial registration (NCT05233761): https://clinicaltrials.gov/study/NCT05233761 clinicaltrials

PubMed record: https://pubmed.ncbi.nlm.nih.gov/39167421/ pubmed.ncbi.nlm.nih

Full‑text article (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC11701282/ pmc.ncbi.nlm.nih

---