The Longevity Vault with Kat Fu

This is a free preview of a paid episode. To hear more, visit thelongevityvault.substack.com➤ “Every morning my body kicks me awake between 2:30–3:30 am. No matter what I do—no screens, peppermint tea, chamomile tea—I still wake up. Then I drift in and out until ~5:30 am, when I finally give up and get out of bed.It has been years of this.My doctor says it’s normal for my age, but I’m exhausted. Why isn’t anything working?”This is a question I’m most often asked — in many variations, but always with

Resources:Vitamin D testing optionsSleep OS Hormones: https://thelongevityvault.com/sleep-os/hormones/A new case published in The Journal of the Norwegian Medical Association (Sept 2025) describes a healthy man who developed acute kidney failure after six months of self-supplementing vitamin D.This short episode unpacks what happened, why “moderate” doses can accumulate unpredictably, and how genetics, cofactors, and testing shape individual responses.Key points:* Even within guideline limits,

Sleep OS Hormones: https://thelongevityvault.com/sleep-os/hormones/The Longevity Vault: https://thelongevityvault.com/When we think about circadian rhythms and sleep, melatonin typically dominates the conversation as the hormone that signals darkness and initiates sleep onset.But what’s not widely understood is that testosterone, estrogen, and progesterone also interact with the brain’s circadian control centers.These hormones don’t just follow the clock’s rhythm—they also help shape

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit thelongevityvault.substack.com/subscribeWhen most people consider heart health optimization, they default to conventional lipid management and saturated fat restriction protocols. This approach, while foundational, overlooks a critical regulatory system that influences cardiovascular disease risk.The emerging research reveals a more sophisticated relationship: your gut microbiome

➤ Someone recently asked me this question, and it perfectly captures what so many people experience but can't explain:"I've had this issue for a very long time now where I wake up too early and then drift in and out of restless sleep for the last 1-2 hours of sleep and none of the standard sleep habit tricks help. I will go to bed at around 22:00 and consistently wake up around 3 am, falling in and out of sleep 3-4 times until 5 am with a lot of movement in my sleep causing achiness as well."They'd

Resources:Sleep OS Hormones → https://thelongevityvault.com/sleep-os/hormones/Subscribe for more evidence-based guides on sleep in midlife and beyond → https://thelongevityvault.substack.comHow Do You Fall Back Asleep? — The Question That Reframed Everything I Knew About SleepMost people optimize sleep onset—earlier bedtime, caffeine changes, darker rooms—yet still wake around 2–3 a.m. and drift until morning.This short episode explains why the issue isn’t getting to sleep; it’s what happens to your