The Longevity Vault | Kat Fu, M.S., M.S. | Substack

Does "deep sleep" clear Alzheimer's proteins?

New human data (Oct 2025) shows "time in deep sleep" predicted 0% of amyloid removal—here’s what does:

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Are My Hormones Affecting My Sleep?

7:04

“My friend the same age sleeps fine—why am I the one awake at 3 AM?”

You’ve fixed your sleep hygiene, diet, even tried meditation—yet 3 AM wake-ups continue. Here’s why standard advice fails after 50, and what your…

Feb 20 • Kat Fu, M.S., M.S.

Hormone Supplements Don’t Always Deliver, Here’s Why:

Raising testosterone, or estrogen isn’t enough. Sleep depends on how effectively your body can use them—and that responsiveness can be supported, even…

Feb 14 • Kat Fu, M.S., M.S.

Your Brain Makes Its Own Sleep Drug—And It’s More Sophisticated Than Valium

Millions turn to Valium-type medications for sleep, but a 2025 study shows they disrupt sleep architecture. Meanwhile, your brain makes…

Feb 6 • Kat Fu, M.S., M.S.

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.

Feb 1 • Kat Fu, M.S., M.S.

Does "deep sleep" clear Alzheimer's proteins?

Surprisingly, the answer is no. New data (Oct 2025) decouples "time in deep sleep" from clearing of amyloid proteins. Here’s what does:

Jan 24 • Kat Fu, M.S., M.S.

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Podcasts

The Longevity Vault with Kat Fu

"Why Can't I Stay Asleep Longer Than 5-6 Hours?"

How Do I Stay Asleep?

Do you need sunlight in your eyes to sleep better?

Is “sunlight in the eyes” actually good for you? Your body has a clock inside it. This clock helps tell you when to feel awake, when to feel sleepy…

Jun 8 • Kat Fu, M.S., M.S.

Why Sleep Gets Easier to Break After Midlife

Today's piece is a little different: Scott Anderson interviewed me about sleep after midlife, why a full night can still leave someone unrested, what…

Jun 1 • Kat Fu, M.S., M.S. and Scott C Anderson

7:44

"Why Can't I Stay Asleep Longer Than 5-6 Hours?"

Without Addressing Sleep Architecture After 3AM, You'll Keep Drifting In and Out Instead of Reaching Deeper Stages

May 20 • Kat Fu, M.S., M.S.

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…

May 4 • Kat Fu, M.S., M.S. and Dr Mike Hunter

What Causes Circadian Sleep Disruption? 10 Underappreciated Factors

The suprachiasmatic nucleus is the master pacemaker, but it is not the only clock. Every organ — the liver, gut, kidneys, adrenal glands, skeletal…

Apr 27 • Kat Fu, M.S., M.S.

Can one night of sleep flag dementia risk?

How you sleep is tied to memory, mood, blood pressure, blood sugar, and whether you can show up for the people and activities that matter to you. For…

Apr 20 • Kat Fu, M.S., M.S. and Heather Hausenblas, PhD

Top posts

"Why Can't I Stay Asleep Longer Than 5-6 Hours?"

May 20 • Kat Fu, M.S., M.S.

"How Do You Fall Back Asleep?" The Question That Made Me Rethink Everything About Sleep

Jan 24 • Kat Fu, M.S., M.S.

3 A.M. Wake-Ups: It’s Not Just Stress

Nov 28, 2025 • Kat Fu, M.S., M.S.

The Underrated Biomarker That Predicts Stroke & Dementia Risk

Jan 26 • Kat Fu, M.S., M.S.

Are 3–5 a.m. wake-ups disrupting the REM sleep that protects your brain after 50?

Jan 18 • Kat Fu, M.S., M.S.

The Vault 5-Part Sleep Clarity Masterclass

Have you been ‘treating’ or ‘solving’ bad sleep? (Part 2 of the Vault 5-Part Sleep Clarity Masterclass)

Let's talk about solving it.

Feb 15 • Kat Fu, M.S., M.S.

Poor sleep is not the problem

If you see yourself in Person A, you’re in very familiar company. My aim is to help you move toward Person B: Person A: “I do everything right for…

Jan 27 • Kat Fu, M.S., M.S.

The CEO's Nighttime Peeing Problem—A Case Study

Why ‘No Water After 7PM’ Fails

Nov 26, 2025 • Kat Fu, M.S., M.S.

Is sleep decline just age—or something you can still change?

Hormone Decline ≠ Hormone Dysfunction

Nov 24, 2025 • Kat Fu, M.S., M.S.

Your 90% sleep solution (Part 5 of the Vault 5-Part Sleep Clarity Masterclass)

= finding your 90% sleep problem

Nov 20, 2025 • Kat Fu, M.S., M.S.

You can watch Netflix at night. And in bed (if you like) (Part 4 of the Vault 5-Part Sleep Clarity Masterclass)

And still get "Person B" sleep. Here's the insight:

Nov 18, 2025 • Kat Fu, M.S., M.S.

Removing Sleep Obstacles ≠ Creating Sleep Capacity (Part 3 of the Vault 5-Part Sleep Clarity Masterclass)

I had a 5,000-step sleep ritual. My friend just... went to bed. Here's the "aha moment" I learned from him:

Nov 14, 2025 • Kat Fu, M.S., M.S.

The 2-phase solution for sleep issues (Part 1 of The Vault 5-Part Sleep Clarity Masterclass)

Why one solution doesn't fit all sleep issues

Nov 7, 2025 • Kat Fu, M.S., M.S.

Why Isn’t Melatonin Helping?

Is Your Melatonin Actually Helping Your Sleep?

The chronobiology of melatonin & why it hasn't delivered consistent results you hoped for

Mar 9 • Kat Fu, M.S., M.S.

Melatonin as a Longevity Molecule? Safety Data, Metabolic Risks, and Antioxidant Promise

Melatonin Risks at High Dose: Reproductive, Neural, Metabolic , and Immune Trade-offs

Dec 20, 2025 • Kat Fu, M.S., M.S.

Is Melatonin Helping or Making It Worse? (Sleep Problems ≠ Melatonin Problems)

You don’t need a higher dose—just a more precise approach.

Oct 27, 2025

Sleep Problems ≠ Melatonin Problems

You don’t need a higher dose—just a more precise approach.

Oct 26, 2025 • Kat Fu, M.S., M.S.

Is stress the reason I can’t stay asleep?

7:35

"I keep waking up at 3 a.m. with my mind racing. Is it just stress?"

The version of "stress" most people have in mind — work pressure, responsibilities, things keeping them up mentally— is usually only part of the…

Mar 4 • Kat Fu, M.S., M.S.

When Sleep Apnea Doesn’t Look Like Sleep Apnea

A guide for midlife adults who don’t fit the “classic” apnea mold. Guest post collaboration between Chris Gouveia, MD (SleepDocs) and Kat Fu, M.S., M.S…

Feb 16 • Kat Fu, M.S., M.S. and Chris Gouveia, MD

The 3 Midlife Sleep Patterns Linked to Early Brain Aging

Why "normal" sleep struggles in mid-life may be accelerating cortical thinning, memory consolidation issues, and executive function decline—even if…

Jan 25 • Kat Fu, M.S., M.S.

"How Do You Fall Back Asleep?" The Question That Made Me Rethink Everything About Sleep

Why 3am wake-ups aren't just about finding the right breathing technique

Jan 24 • Kat Fu, M.S., M.S.

0:25

3 A.M. Wake-Ups: It’s Not Just Stress

For years, I slowed my breath, focused on sensations—and stayed alert anyway.

Nov 28, 2025 • Kat Fu, M.S., M.S.

Recent posts

Do you need sunlight in your eyes to sleep better?

Is “sunlight in the eyes” actually good for you? Your body has a clock inside it. This clock helps tell you when to feel awake, when to feel sleepy…

Jun 8 • Kat Fu, M.S., M.S.

Why Sleep Gets Easier to Break After Midlife

Today's piece is a little different: Scott Anderson interviewed me about sleep after midlife, why a full night can still leave someone unrested, what…

Jun 1 • Kat Fu, M.S., M.S. and Scott C Anderson

"Why Can't I Stay Asleep Longer Than 5-6 Hours?"

Without Addressing Sleep Architecture After 3AM, You'll Keep Drifting In and Out Instead of Reaching Deeper Stages

May 20 • Kat Fu, M.S., M.S.

7:44

Does Poor Sleep Make Your Organs Age Faster?

A just-published Nature study, “Sleep chart of biological ageing clocks in middle and late life,” asked a simple but important question: does sleep…

May 18 • Kat Fu, M.S., M.S.

Does Growth Hormone Affect Dementia Risk?

Growth hormone usually enters the longevity conversation through body composition. That makes sense. Growth hormone affects muscle, bone, fat…

May 11 • Kat Fu, M.S., M.S.

The latest from

Kat Fu, M.S., M.S.

Do you need sunlight in your eyes to sleep better?

What Are Kat’s Top Sleep Tips?

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Why Many Sleep Tips Don't Work & Don't Last

Without addressing this layer first, every sleep strategy eventually hits a ceiling. Here's an overlooked reason sleep routines stop working or don't…

Feb 12 • Kat Fu, M.S., M.S.

0:28

What 10,000+ Hours of Lost Sleep Taught Me: Kat’s 37-Part Sleep Mastery Protocol

Sleep recovery moves that turned 10,000+ hours of lost sleep into consistent 8-hour nights for me—distilled so you can learn them all in <5 minutes:

Oct 2, 2025 • Kat Fu, M.S., M.S.

3 “Odd” Sleep Strategies Backed by Research (& My Results)

[Vault Insider] Not melatonin, not blue light — these underappreciated levers reshaped my sleep quality.

Aug 25, 2025 • Kat Fu, M.S., M.S.

0:17

Unpopular Take: Mouth Taping Is One of the Most Ill-Advised Sleep Optimizations for People With Undiagnosed Breathing Disorders

The difference between reducing sleep disruptions from dry mouth versus fundamentally improving sleep quality through addressing structural airway…

Aug 6, 2025 • Kat Fu, M.S., M.S.

The Longevity Vault

The Longevity Vault

The Longevity Vault by Kat Fu — the platform that guides you to build your personalized roadmap, based on your risk factors & data, so you can age slower, think better & extend your prime. Its flagship, Sleep OS, helps you reduce 3 a.m wakeups.

Vault Insider Exclusive

Does Growth Hormone Affect Dementia Risk?

Growth hormone usually enters the longevity conversation through body composition. That makes sense. Growth hormone affects muscle, bone, fat…

May 11 • Kat Fu, M.S., M.S.

I've been taking Benadryl every night for years. Is it bad?

I’ve been taking Benadryl every night for ~3 years now. It’s the only thing that knocks me out. Is it bad?” This question appeared in my inbox recently…

Jan 19 • Kat Fu, M.S., M.S.

The LDL-C Risk Healthy Eaters Overlook: Longevity-Supporting Microbes vs. Inflammatory Microbes for Cardiovascular & Brain Health Protection

How to turn an already strong lifestyle into lower LDL-C, reduced cardiovascular risk, and better long-term brain health by targeting gut microbes that…

Dec 25, 2025 • Kat Fu, M.S., M.S.

6-Part Framework To Detect Early Aging from Routine Labs & Reverse Course (SPIRAL)

Most decline starts inside the normal range. SPIRAL shows you where to act early.

Dec 8, 2025 • Kat Fu, M.S., M.S.

Kidney stones: Is avoiding spinach enough?

Most oxalate is made inside your body—not just from spinach. Here’s what that means for kidney stone prevention.

Dec 8, 2025 • Kat Fu, M.S., M.S.

Which Supplements & Habits Support Longevity?

The Real Reason Our Doctors Can’t Flag Early Aging & Decline

If We Rely on “Normal” Lab Ranges, We’ll Miss the First Signs of Decline.

Mar 28 • Kat Fu, M.S., M.S.

Is dietary cholesterol required for good human health?

A deep-dive on how dietary cholesterol might or might not affect your LDL-C Cholesterol is one of the body’s most tightly regulated and energetically…

Mar 16 • Kat Fu, M.S., M.S. and Dr Mike Hunter

Can 3–5 a.m. wakeups affect cancer risk?

Sleep touches nearly every process that matters for cancer biology: immune surveillance, DNA repair, hormone balance (especially sex hormones), insulin…

Mar 11 • Kat Fu, M.S., M.S.

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…

Feb 8 • Kat Fu, M.S., M.S.

0:25

The Underrated Biomarker That Predicts Stroke & Dementia Risk

It’s not HRV, glucose, or inflammation. But it predicts your risk of stroke, dementia, and kidney decline decades before symptoms. When was the last…

Jan 26 • Kat Fu, M.S., M.S.

3 Reasons Why Routine Medical Testing Isn’t Enough for Proactive Aging—In Frequency, Depth or Breadth (What You Need Instead)

You shouldn’t have to run expensive specialty tests just to get direction; with your lived experience, routine labs, and a clear decision framework, you…

Jan 22 • Kat Fu, M.S., M.S.

Slower aging, better sleep, actionable labs: Your 2026 Longevity Launchpad

Longevity work becomes powerful when last night’s sleep, today’s meals, and your next blood draw are all pulling in the same direction. This 2026…

Jan 20 • Kat Fu, M.S., M.S.

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Vitamin C, calcium, iron & D3: they can never hurt… right?

+ 3 categories of supplements I avoid 100% of the time.

Jan 16 • Kat Fu, M.S., M.S.