Welcome back to Deep Cycles. Here is the short version, because your time is better spent sleeping than reading.
The big story this quarter is melatonin. In November 2025, new data presented at the American Heart Association raised a serious question about taking it long-term. I want to walk you through what the research does and does not show, because the headlines have outrun the evidence in both directions.
There is more inside this issue:
- Deep sleep is one of your brain's best overnight defenses against Alzheimer's risk, and there is a practical plan to protect it.
- Our podcast, Powered by Sleep, is now live, and Episode 04 features Dr. Elise Grenier on why women sleep differently.
- We launched CBDForSleep.com, a free library of published clinical research on CBD, hemp, and sleep.
As always, our goal is the one we started with: not to knock you out, but to give you more of the deep and REM sleep that actually restores you. The science is real, and a good night's sleep belongs to you.
Our FDA-registered, double-blind, placebo-controlled, randomized crossover Phase 2 trial enrolled adults with severe insomnia, and used validated wrist-worn actigraphy (Whoop devices) to objectively measure sleep architecture. The results, published in the Journal of Clinical Sleep Medicine, showed that our proprietary CBD + terpene formulation — 300 mg CBD, zero THC, zero melatonin — can significantly increase the proportion of the night spent in the sleep stages that matter most.
The Melatonin Reckoning
For years, melatonin has been marketed and sold as a safe, natural sleep aid. New data is complicating that story.
In November 2025, a large study presented at the American Heart Association's Scientific Sessions found that, among adults with chronic insomnia, those who relied on melatonin for a year or longer had a markedly higher rate of heart failure, heart-failure hospitalization, and death from any cause. The analysis drew on the health records of more than 130,000 adults.
Two things matter as much as the finding itself. First, the research has not yet been peer-reviewed, and an association of this kind cannot prove that melatonin caused these outcomes. Chronic insomnia carries its own cardiovascular risk, and the people who reach for melatonin night after night may simply be less well to begin with. Second, this was about long-term, daily use, not the occasional dose before a red-eye flight.
So the honest takeaway is not that melatonin is not necessarily dangerous, but it may be. A supplement marketed as harmless deserves the same scrutiny as anything else you take every night for years, and only additional prospective clinical research will establish melatonin's health risks.
It is also worth saying plainly: Defined Sleep contains no melatonin. Our formulation was designed to support the body's own deep and REM sleep, not to override the brain's clock with a nightly dose of a hormone.
We built something we wish had existed when we started Defined Sleep. CBDForSleep.com is a free, non-commercial library of published clinical research on CBD, hemp, and sleep, collected in one place. If the melatonin story teaches us anything, it is that people deserve to read the evidence for themselves. This is our attempt to make that easy.
The Brain-Protection Angle
Deep sleep is not downtime. It is when the brain runs its overnight maintenance, clearing metabolic waste, including the proteins associated with Alzheimer's risk. In this article I lay out what the science actually shows and, just as important, what you can do about it.