Does Growth Hormone Affect Dementia Risk?
How to Support Growth Hormone After Midlife Without Taking Hormones
Is the gut-sleep link finally real, or wellness hype?
What if your gut was influencing how well you sleep each night?
GABA — gamma-aminobutyric acid — is one of the brain’s main calming molecules, and many sleep medicines work by boosting its effects. Gut microbes can also make GABA. But whether that gut-made GABA reaches the brain, and whether it matters for sleep, is a question the field is only now beginning to answer with human data.
GABA in blood is thought to reach the brain in only small amounts, if at all, under typical conditions — and human evidence about GABA crossing the blood–brain barrier is currently limited. Few human studies measure gut GABA and sleep at the same time, and even fewer also measure brain GABA.
So does gut-produced GABA affect human sleep — and if so, how?
This review will discuss:
What is gut-produced GABA, and how do microbes make it?
What pathways exist for gut-made GABA to affect human sleep (even if it does not cross the blood-brain-barrier)?
Human evidence linking gut GABA to sleep
Practical implications: is optimizing gut-made GABA a practical strategy for improving your sleep?
Is the gut-sleep link finally real, or wellness hype? Read Post »
Is your gut spiking cortisol at 3 a.m?
Sleep and the gut.
Two areas of longevity science I keep coming back to — both in my own work and in my own health. I think the gut-sleep connection is one of the more underappreciated intersections in health, and it’s something I’ve wanted to explore in a focused conversation for a while.
Today I get to do that — through a written Q&A with Scott C. Anderson.
Scott is a science journalist and co-author of The Psychobiotic Revolution: Mood, Food, and the New Science of the Gut-Brain Connection — a National Geographic bestseller he wrote alongside John F. Cryan and Ted Dinan, the researchers who coined the term psychobiotics. He also writes on Substack about the gut-brain connection.
I asked Scott six questions about the gut-brain axis, cortisol, probiotics, and what the research says about improving sleep through the microbiome.
Here’s what he had to say:
Everybody talks about growth hormone. Almost nobody talks about what controls it.
Physiological studies show that total daily GH output begins to fall in our 30s largely because the bursts of GH released become smaller.
In longevity circles, that observation is often interpreted in a linear way: GH decreases with age, so perhaps the solution is to increase GH again.
Yet major endocrine reviews and guideline statements have not endorsed raising GH as an anti-aging approach in otherwise healthy adults. Trials in older adults without GH deficiency have produced modest improvements in body composition but also higher rates of adverse effects, and there is no GH-raising therapy approved specifically for anti-aging.
The reason is that GH is not a single dial that can be turned up.
GH output emerges from a regulatory network in the brain involving multiple interacting inputs:
growth hormone–releasing hormone (GHRH), which stimulates GH release
somatostatin, which suppresses GH release
ghrelin, which amplifies GH release
These inputs interact continuously with sleep depth, metabolic state, and reproductive hormones such as testosterone and estrogen.
So when GH changes across the lifespan, the more complete explanation lies in the upstream regulators.
In this article we will look at:
what growth hormone–releasing hormone (GHRH) is and how it stimulates GH production
the lesser-known role of GHRH as a sleep-promoting neuropeptide tied to deep sleep
what tends to change after midlife in the sleep–GHRH–GH axis
whether aging itself is the primary driver of those changes — or whether age is partly a proxy for modifiable factors
Let’s get started.
Everybody talks about growth hormone. Almost nobody talks about what controls it. Read Post »
Your Brain Makes Its Own Sleep Drug—And It’s More Sophisticated Than Valium: progesterone for sleep
Your brain produces allopregnanolone, a metabolite of progesterone, that acts on the same GABA-A receptors as benzodiazepines—but reaches receptor sites that sleep medications cannot access. Where benzodiazepines produce short bursts of sedation that suppress deep sleep and REM, allopregnanolone generates steady background calming that preserves natural sleep architecture. Allopregnanolone activates both synaptic and extrasynaptic (δ-containing)
Can exercise help you stay asleep? 2025–2026 research + 5 ways to use it now
You already know that sleep is not just about feeling rested.
Poor or fragmented sleep affects memory, mood, blood sugar, blood pressure, and how much reserve you feel you have for the things you care about most. For many, the options that get suggested first are medications or supplements, and movement often does not enter the conversation.
Exercise, however, is one of highest impact health (& sleep improvement) strategy you fully control.
It interacts with your circadian rhythm, your stress response, your muscles, and your brain. It can potentially deepen your sleep, shorten how long you lie awake during your sleep, and reduce the emotional “charge” around insomnia.
It also has its own direct links to brain health and dementia risk.
Over just the last few years, research on exercise and sleep has accelerated: large wearable-device datasets, pooled analyses of dozens of trials, and brain-imaging work now give a more 3-dimensional view of how movement interacts with your sleep than we have ever had before.
When you look at this newer research as a whole, every decision to move a bit more becomes a positive step you are taking towards sleeping, thinking, and functioning better in the years ahead.
In this article, we’ll cover
– How different exercise types can influence your sleep quality and sleep structure
– What large, recent pooled data sets suggest about how much & what kind of exercise seems most effective for sleep
– Which exercise modes—can influence brain circuits in a direction that looks more like good sleepers.
– What an Alzheimer’s study suggests about exercise and sleep architecture at the level of brain pathology.
– Finally, we’ll cover 5 actionable strategies to help you translate all of this into an exercise approach that supports better sleep, more daytime energy, and longevity.
Let’s get started.
Can exercise help you stay asleep? 2025–2026 research + 5 ways to use it now Read Post »
4 Hormone Misconceptions Keeping You From Fixing Your Sleep—At Any Age
Sleep struggles in your 50s, 60s, and beyond aren’t “just aging”—and, they’re often solvable.
4 Hormone Misconceptions Keeping You From Fixing Your Sleep—At Any Age Read Post »
Does Short Sleep Impair Blood Sugar Control (Even with a Healthy Diet?): We review the 2023-2025 data (& 10 simple ways to get an extra 20-40 minutes of sleep tonight)
Chronic short sleep—habitually getting less than the body requires—is independently associated with impaired blood sugar regulation and higher type 2 diabetes risk, even when diet and lifestyle factors are accounted for. A 2024 analysis of 247,000 adults published in JAMA Network Open found that sleeping approximately 5 hours per night was linked to a 16%
Hormone Decline ≠ Hormone dysfunction.
The assumption that worsening sleep after midlife is inevitable because hormone levels decline misses a large part of the picture. Decline and impairment operate differently—and the distinction matters because the vast majority of what impairs hormone function is modifiable. This is why some adults at 70+ sleep well while others at 40 struggle. Age is
Are My Hormones Affecting My Sleep? An Overlooked Reason Hormone Therapy Falls Short
Testosterone, estrogen, and progesterone each influence different aspects of sleep—deep sleep depth, REM timing, and mid-sleep fragmentation patterns—but hormone levels alone do not determine whether those effects occur. What matters equally is receptor sensitivity: how many receptors are available in brain regions like the hypothalamus and basal forebrain, how efficiently they bind, and whether the
Are My Hormones Affecting My Sleep? An Overlooked Reason Hormone Therapy Falls Short Read Post »