Cured Nutrition Review – A 2025 Meta-Analysis Changed What We Thought About CBN

We Are Updating a Position We Have Held

This review contains a genuine change of view, so we are putting it at the top rather than burying it.

Had this brand come through our queue two years ago, we would have been dismissive of its central claim. CBN — cannabinol — is sold across this entire industry as the sleep cannabinoid, and the evidence for that was, until recently, notably thin. New evidence has changed the picture, and it changed it in a direction we did not expect.

We have corrected ourselves before in this series — most recently when we said one brand alone had published verified potency data and then found a second. Updating in public is the price of taking evidence seriously.

What the Evidence Looked Like in 2021

A 2021 review — pointedly titled “Cannabinol and Sleep: Separating Fact from Fiction” — set out the position clearly.

• Clinical studies investigating CBN were limited.
• Most human studies dated from the 1970s and 1980s — half a century old, from before modern sleep methodology.
• No published clinical trials investigating CBN against validated sleep questionnaires or polysomnography were identified at all.
• Conclusion: insufficient published evidence to support sleep-related claims.

That is about as clear a “not established” as this field produces, and it is the position we would have applied. The widely-repeated belief that CBN is sedating appeared to rest on very little.

What the 2025 Meta-Analysis Found

Then a 2025 systematic review and meta-analysis of randomised studies examined cannabinoid effects on subjective sleep quality in people with and without insomnia.

A systematic review and meta-analysis of randomised studies sits near the top of the evidence ladder we apply across this site — above single trials, well above observational work, and in a different universe from the testimonials that pass for evidence in most of this industry.

So the honest summary is that CBN moved from “no supporting trials identified” to “named as a driver of effect in a randomised meta-analysis” in roughly four years. That is a real change, and pretending otherwise to preserve a sceptical posture would be dishonest.

Four Things That Finding Does Not Mean

Having credited the evidence properly, here is what it does not establish — because this is exactly the kind of result that gets overstated in marketing within a week of publication.

The grouping point is the one that deserves most caution. THC is a compound nobody doubts is psychoactive and sedating at appropriate doses. Bundling it with CBN and reporting that the pair drove the effect leaves open how much of the work THC was doing.

And subjective versus objective matters a great deal in sleep research specifically, because sleep is a domain where expectation effects are powerful and where how rested you feel and what your brain actually did overnight can diverge substantially.

The Same Paper Is Bad News for Plain CBD

This is the half of the finding that will not appear in anybody’s marketing, and it is arguably more consequential.

Consider how much CBD is sold specifically for sleep. We have reviewed a great many CBD brands for this site, and sleep is among the most common stated reasons people buy it. On this analysis, CBD alone did not beat placebo on the outcome those buyers care about.

This is consistent with the position we have taken throughout. We have written in every CBD review that the evidence base is thinner than the marketing implies — and here is a randomised meta-analysis finding CBD alone did not reach significance on sleep while other cannabinoids did.

The practical consequence for a buyer is a genuinely useful piece of guidance: if sleep is why you are buying a cannabinoid, the evidence points toward products containing CBN rather than CBD-only formulations. That is an unusual thing for us to be able to say, because it is a positive recommendation derived from evidence rather than from a company’s claims.

Batch Testing, Published

On the company itself, the testing position is the strongest thing we found.

Cured Nutrition states it performs third-party testing with every product and batch, and that these can be used to verify potency and purity.

Set that against what we have found elsewhere in this series. One kratom retailer described a detailed five-step testing protocol and then asked customers to email if they wanted certificates — which cannot be checked before purchase or used to compare sellers. Another brand’s marketing praised companies that publish lab reports alongside their products while linking none itself.

The honest limit: this is the company’s stated practice, and we did not independently verify a certificate or find an independent assay of a Cured Nutrition product. We are crediting a policy, not a verified result — which is a meaningful step below the brands in this series whose products we could see independently tested.

Eight Actives in One Capsule

Here is our main criticism of the product itself, and it is a formulation argument rather than a safety one.

Zen contains:

Eight actives, four of which are sedative herbs doing broadly the same job. Two problems follow.

First, attribution becomes impossible. If it works for you, you have no idea which ingredient did it — so you cannot buy that one cheaply on its own, and you cannot drop the seven that did nothing. You are locked into the whole stack forever.

Second, and more importantly, capsule volume is finite. Studied doses of these ingredients are not small — the lion’s mane trial below used three grams a day, and typical studied ashwagandha and valerian doses run to several hundred milligrams each. Eight ingredients at studied doses will not fit in a reasonable capsule, so something has to give, and what gives is the dose of each.

Credit where it is due: the ingredients are named individually rather than hidden inside a proprietary blend, which means the doses are at least checkable. Check them. That is a real advantage over the products that will not tell you.

The Lion’s Mane Number to Check

Functional mushrooms are central to this brand’s positioning, so here is the benchmark to measure any of them against.

Three grams a day is the number. Hold any lion’s mane supplement label against it — and note that a mushroom appearing eighth in a list of eight ingredients is very unlikely to be delivering three grams.

Two caveats that rarely get mentioned. The trial was in people with cognitive impairment, not healthy adults seeking sharper thinking — results in a clinical population do not automatically transfer.

That reframes the purchase entirely. This is not a course of treatment producing a durable change — it is an ongoing subscription to an effect that stops when you do. Anyone budgeting for it should be pricing it as a permanent monthly cost, not a temporary intervention.

What We Could Not Find Out

Two significant gaps, stated plainly rather than glossed over.

• Pricing. We could not establish cost per serving or cost per milligram, which means we cannot place this brand on the running cost comparison we maintain across this series — where the range runs from 2 cents to 23 cents per milligram of CBD.
• The guarantee. We could not establish refund or return terms. Given that guarantees have been the single most decisive factor in several reviews here — ranging from 90 days with postage covered down to 15 days unopened-only — this is a material gap.

Both are things you should establish before ordering, and neither is a criticism of the company so much as a limit on what this review can tell you. Ask what happens if it does not work for you, and get the answer in writing.

Side Effects and Who Should Not Use It

Speak to a clinician first if you are:

• Pregnant or breastfeeding.
• Taking prescription medication. Cannabinoids interact with drugs metabolised via liver cytochrome P450 enzymes, including some blood thinners and anti-epileptics.
• Taking any sedative, benzodiazepine, sleep medication or drinking alcohol. This product stacks a cannabinoid with four sedative herbs — combined sedation is the obvious risk and the one most likely to be underestimated.
• Living with liver disease or raised liver enzymes.
• Taking thyroid medication, or living with a thyroid condition — ashwagandha has been associated with thyroid hormone changes.
• Living with an autoimmune condition, given the immunomodulating claims made for medicinal mushrooms.
• Due to have surgery — tell your anaesthetist about sedative supplements.

Do not drive after taking a sleep product, and be careful the first time you try anything stacking this many sedatives. None of these products is FDA-approved to diagnose, treat, cure or prevent any disease.

How It Compares

The unusual shape of this one: the ingredient has better evidence than most brands here, and the company has less verifiable information than most. Those normally run the other way round.

Pros and Cons

Who Should Buy It

Buy a CBN product rather than a CBD-only one if sleep is your reason. That is the evidence-led recommendation from this review, and it applies whether or not you buy this particular brand. The 2025 meta-analysis found CBD alone did not reach significance; CBN was named among the drivers that did.

Prefer the simpler product over the eight-ingredient one. If CBN is the evidence-backed component, a CBN oil tells you what you are taking and how much. Zen’s stack makes the active dose unknowable and attribution impossible.

Establish price and guarantee before ordering, because we could not, and both have been decisive in other reviews on this site.

Check the lion’s mane dose against 3,000mg a day if that ingredient is why you are buying, and price it as an ongoing cost given the effect faded after stopping in the trial.

Do not buy it for weight loss. There is no good evidence cannabinoids produce it, and none of this has been studied alongside GLP-1 medications.

Limitations of This Review

We have not bought, used or independently tested any Cured Nutrition product, and we could not establish pricing or guarantee terms, which is a larger gap than usual — those two factors have decided several ratings elsewhere in this series.

We read both the 2021 review and the 2025 meta-analysis through summaries and abstracts rather than the full papers. That is a real limitation on a review whose central section is an evidence update: we cannot speak to the meta-analysis’s inclusion criteria, how many studies contained CBN versus THC, effect sizes, heterogeneity, or risk-of-bias assessment. Given that CBN and THC were grouped, the number of CBN-containing studies could be small.

The testing claim is the company’s stated practice, not something we verified by reading a certificate, and we found no independent assay of any Cured Nutrition product — so unlike several brands in this series we cannot tell you whether its labels are accurate. Our formulation criticism concerns doses we did not read from the label; it is an argument from capsule volume and studied doses, and it is possible individual amounts are higher than we assume — which is precisely why we tell you to check rather than asserting they are low.

The Mori 2009 figures concern one trial in a clinical population and should not be read as establishing benefit in healthy adults. None of this is medical advice, and persistent insomnia is a reason to see a doctor rather than to buy a supplement.

Frequently Asked Questions

Verdict

This review contains a change of view and we would rather say so than quietly adjust. In 2021 a review titled Cannabinol and Sleep: Separating Fact from Fiction found CBN studies limited, mostly from the 1970s and 1980s, with no published trials against validated sleep questionnaires or polysomnography and insufficient evidence for sleep claims. We would have applied that position.

A 2025 systematic review and meta-analysis of randomised studies found that only treatments incorporating THC and/or CBN significantly improved subjective sleep against placebo, with those compounds largely driving efficacy. That sits near the top of our evidence ladder, and CBN went from “no supporting trials identified” to “named as a driver of effect” in about four years.

Four caveats keep it honest: the outcomes were subjective reports rather than polysomnography; CBN was grouped with THC, so how much work THC was doing is unclear; the result says nothing about whether any product contains a comparable dose; and it is a category finding, not a verdict on this brand.

The same paper carries the finding nobody will market: interventions with CBD alone did not demonstrate a statistically significant effect. After reviewing a great many CBD brands sold substantially for sleep, that is a striking result — and it is consistent with the scepticism we have applied throughout. If sleep is your reason, the evidence points to CBN over CBD-only products.

On the company: stated third-party testing on every batch is the right standard, and better than sellers we have criticised for emailing certificates on request or praising published lab reports while linking none. But it is a stated policy rather than a verified result, and we found no independent assay of any product here — which is where the brands we rated highest pull ahead.

Zen is where we part company with the formulation. Eight actives, four of them sedative herbs doing the same job. If it works you cannot tell which ingredient did it, and studied doses of eight ingredients do not fit in one capsule — the lion’s mane trial alone used three grams a day, and its benefit faded four weeks after stopping. A long ingredient list reads as generous and often functions as dilution.

And we could not establish the price or the guarantee — two things that have decided ratings elsewhere on this site, and both of which you should nail down in writing before ordering.

Buy the CBN, skip the kitchen sink, and ask the two questions we could not answer.