Nick Norwitz MD PhD

In the storm of the peptide craze, it’s sometimes difficult to separate fact from fiction.

But over the past several years, one thing I’ve learned is that even the most fantastical claims occasionally contain a kernel of valuable truth.

So, when I hear people talking about the “Wolverine Stack,” named after the Marvel superhero famous for being nearly impossible to kill because he can regenerate damaged tissues and regrow parts of his body—my skepticism alarm goes off, just like yours probably does.

Honestly, fair enough.

After all, that kind of regeneration belongs in comic books. (Or perhaps in an axolotl).

When it comes to protecting your long-term brain health, you need to think about fat—specifically visceral fat, the inflammatory fat that accumulates deep within the abdominal cavity, wraps around your organs, infiltrates the liver, surrounds the intestines, and contributes to metabolic dysfunction.

But the story of visceral fat just took a fascinating turn.

A new 2026 study from an international team of researchers spanning Harvard, Israel, and Germany suggests that the more exposure you have to visceral fat over the course of your life, the faster your brain shrinks.

What makes this study particularly compelling is the methodology.

The researchers drew from four previous lifestyle randomized controlled trials in which participants underwent:

When I was 21, my body started attacking itself.

Ulcers opened in my intestines.

Food became dangerous.

There was a real chance I could lose my colon entirely. I was diagnosed with inflammatory bowel disease.

And for years, my life revolved around pain, bathrooms, medications, fear, and this constant question: Why was my gut on fire?

Maybe you’ve heard of brain-derived neurotrophic factor (BDNF).

It’s often called “Miracle-Grow for neurons” and frequently comes up in discussions about enhancing cognitive performance and protecting against dementia.

But what if I told you there’s a compound rumored to be 10 million times more powerful than BDNF?

That’s the buzz around Dihexa.

When I first heard these claims, I had my usual two-pronged reaction:

I once almost burned my house down… with a fish.

I know that’s a strange place to start but bear with me.

My mom makes the most incredible Chilean sea bass. It’s one of my favorite meals. The skin is thick, fatty, and perfectly crisped in a cast-iron skillet with ginger butter.

One day, craving that exact dish, I decided to make it myself.

Mistake.

I need to admit something:

When GLP-1s for weight loss started becoming big and everyone was talking about how they would change obesity medicine, I was a strong skeptic.

This has happened before: medicine and big pharma tell a compelling story about a miracle drug — then years later we find out we didn’t have the whole story, and people ended up harmed, sometimes critically.

However, the more I read about GLP-1s and their newer evolutions, the more my opinion shifted.

In fact, my perspective has even leapfrogged from “these are being overhyped” to “maybe they’re not being hyped enough.”

“This work establishes that damage to aging proteins previously thought to be irreversible can be repaired.”

That’s the line from a new paper published 3 days ago in Nature Communications.

Bold words.

But they’re backed by data showing—for the first time ever—that age-related protein damage can be reversed.

Now, there are caveats. We haven’t found the Fountain of Youth just yet. But I’d be lying if I said this paper didn’t bring us one jump closer.

What if you didn’t need to sleep?

No, seriously!

A new article published in Nature Neuroscience explores a provocative possibility: what if we could replicate the restorative benefits of sleep without ever fully shutting down the brain?

Imagine staying awake for 24 hours a day without compromising memory, cognitive performance, or neurological health.

The trick would be to stop thinking about sleep as an all-or-nothing phenomenon.

I don’t say this lightly: this may be one of the most interesting metabolic drugs I’ve ever reviewed.

Officially, it’s in clinical trials for diabetes.

Unofficially, it may represent something much bigger—a compound that reproduces some of the core metabolic effects of exercise itself.

If the early data continue to hold up, this could reshape how we think about treating insulin resistance, fatty liver, obesity, GLP-1s, and even exercise mimetics.

But before we get to the preclinical data and the human trials, I need to build a bit of biological foundation first.

In the universe of peptides, none is more mysterious — and more misunderstood — than the copper peptide, GHK-Cu.

Legends surround it: that it can:

Reverse wrinkles

Accelerate healing

Even protect against cancer

Mitochondria are often referred to as the “powerhouse of the cell,” as if they’re little batteries.

But they’re so much more than that.

They’re living, breathing, fluctuating, even dancing signaling networks that determine how your body generates energy at the most fundamental level, and even how you age.

In fact, if you look for the signature that distinguishes the longest-lived people — including a recent report on a woman who lived to 117 — what stands out in healthy aging is healthy mitochondria.

But the amazing thing about mitochondria is that, unlike a battery or an engine in a car, they can recover, heal, and renew themselves. And you can make them do this, starting today with free tools – but also, cutting-edge tools like performance enhancing mitochondrial peptides and hormones.

There is a common medication that costs as little as $1 a day that has recently begun attracting attention for its potential effects on cardiovascular disease, dementia risk, metabolic health, and even overall longevity.

It’s called tadalafil.

Most people know tadalafil as a treatment for erectile dysfunction, though it also carries FDA approval for conditions like benign prostatic hyperplasia and pulmonary arterial hypertension.

But a growing number of clinicians and researchers are now asking a much broader question:

What if tadalafil has meaningful effects on the heart, brain, blood vessels, exercise performance, and perhaps even mortality?

There’s a simple little peptide that’s becoming increasingly popular for the treatment of gut inflammation.

It’s called KPV.

And it’s something I wish I’d had access to eight years ago.

Let me start by telling you something personal, and then we’ll get into the science.

I want to rewind about eight years, to the day of my college graduation.

What do you do if your GLP-1 stops working?

Or maybe it never worked all that well in the first place?

Those are not a hypothetical questions.

While GLP-1 drugs have helped millions of people lose weight, some people barely respond, some experience debilitating side effects, and many wonder whether the benefits will eventually fade.

So today we’re going to tackle the difficult questions:

I saw something the other day that genuinely pissed me off.

I thought it was just an internet joke, but when I saw it in real life, the anger center of my brain lit up like a candle.

It was a plaque that said, “Don’t confuse your Google search with my medical degree.”

Now, before we go any further in this letter, which is going to be about why smart people believe dumb health ideas, I want to give you organically what rolled off my metaphorical tongue into a post I made after encountering that disturbing plaque:

I’m about to say what a lot of people and patients want to say, but might not have the words for.

Surviving long periods without food has shaped human evolution.

In both ancient and modern societies, fasting has been practiced by billions of people and been used to treat diseases ranging from autoimmune and inflammatory disorders to neurological disorders, such as epilepsy.

But we still have a limited understanding of the adaptations humans undergo during a prolonged fast, and how these relate to chronic disease.

So, what happens when you fast for one day, two days, three days, or even a full week?

What changes occur across your metabolism, and different organ systems?

Can statins cause Alzheimer’s disease and dementia?

The answer is uncomfortably complex.

And in my experience, almost no one will give it to you straight.

Let me back up and provide some personal context.

Friends and family come to me all the time asking for a second opinion on whether they should start a statin.

I spent a month obsessed with cottage cheese.

I ate ~36 pounds of the stuff over the course of April.

But I should back up.

I recently released an article about my personal experience taking the new GLP-1 receptor agonist, retatrutide.

I wasn’t trying to lose weight. But I did want to explore what happened under my metabolic hood, so to speak.

A new study in Cell Metabolism has me scratching my chin and rethinking my recipe book.

The paper reports that a compound found in aged garlic may protect both the brain and skeletal muscle from age-related decline.

As far-fetched as that sounds, the data are surprisingly strong.

There are even human clinical evidence supporting the idea that this compound could has anti-aging potential.

Quoting the researchers: [our] findings raise “an interesting possibility of S1PC as a nutraceutical anti-aging compound.”

Yesterday, I ‘accidentally’ got 29,000 steps.

Last week, I hit a bench press personal best.

And this month, my focus and productivity have been at their peak.

Why?

I tried something recently that really kicked me into a new gear.

As a metabolism scientist, I spend my days obsessed with the intricate inner workings of the human body and how they relate to lifestyle interventions, including diet, exercise, supplements, peptides, and many of the other topics we routinely discuss here at StayCurious Metabolism.

But there is a curious observation that, honestly, humbles my entire field.

When you look at some of the longest-lived and healthiest people in the world, they typically aren’t united by any one diet, supplement regimen, or rigorous daily exercise routine.

(Sorry. I know you’re disappointed to know treadmills aren’t the secret to living to 120.)

Instead, what unites the people with the longest lifespans and health spans are strong social connections and a deep sense of purpose.

Muscle & peptides.

If I had to pick the top buzzwords in health and medicine right now, those might be it.

And where they overlap—muscle-building peptides—you run into a dense thicket of multisyllabic names and acronyms that can make even a literary PhD’s head spin: CJC-1295, Ipamorelin, Sermorelin, Tesamorelin, MK-677, Follistatin-344, ACE-031, IGF-1, hGH, and on and on.

So today, the objective is simple: demystify the space.

Author’s Note: The structure of this letter is going to be a bit different from our usual, more narrative style at StayCurious Metabolism.

A new paper came out on a curious driver of Alzheimer’s disease, and as soon as I read it, I texted my mom:

Nick: “[Mom], are you take glucosamine [for your joints]? If so, stop…”

Mom: “Yes, I am. Will Stop.”

You’ll notice the introduction to this letter is different.

I’m not burying the lede, and the tone is one of caution and a bit of negativity.

What causes bloating?

It’s a deceptively complicated question.

And whether you have IBS, IBD, celiac disease, or another functional gastrointestinal disorder, chances are you’ve experienced bloating once or twice… or more.

But again, I ask: what causes it?

There isn’t a single straightforward answer, but one contributing factor is something called leaky gut.

As many of you know by now, I’m a neuroscientist who is himself at high risk for Alzheimer’s disease.

This is due to the fact that I carry two copies of the Alzheimer’s risk variant ApoE4, which is thought to increase my risk of developing Alzheimer’s disease by roughly 10- to 15-fold.

As a result, I leave no stone unturned when evaluating interventions that might help prevent it.

And one of the most interesting, provocative, and promising possibilities to cross my radar recently has been GLP-1 drugs.

Yes, the same blockbuster weight-loss medications you hear about in the news practically every day.

There’s a new weight loss drug that people think could become the biggest drug in history.

It’s called retatrutide.

We’ve discussed it before.

Briefly, in the published trials people are losing a quarter of their body weight, like a snake shedding its skin, or like they just flew through a 20 second body recomposition movie montage.

The power of this compound is insane, outperforming all other weight loss drugs, by a wide margin.

Most organs in our body have a nutrient delivery system, blood vessels, and a waste removal system, called lymphatic vessels.

But my brain is apparently missing the waste disposal part!

(Maybe that’s why it’s packed with completely random animal facts.)

Jokes aside, all of our brains are, for the most part, missing the conventional lymphatic system.

The brain is so densely packed with blood vessels, neurons, and support cells that there simply isn’t room for the lymphatic vessels found throughout the rest of the body.

It’s just about Pet Appreciation Week (often called PAW), which takes place from June 7–13, 2026.

As far as esoteric holidays go, I think this is a great one to acknowledge.

And, on a personal note, now that I am finally settling down in a place where I can have a pet, I’m actually looking to adopt a dog myself.

So, in celebration, I thought I’d blend dogs with health—specifically heart health—in a way that’s hopefully both informative and entertaining.

Let’s talk DOGMATIC: a hypothetical randomized controlled trial.

We might be extremely close to developing treatments that simultaneously blast away fat and build muscle.

Now, I understand why you might be skeptical, or even afraid to hope that something like this is possible.

But the data from both humans and monkeys suggests that it very much is possible… and maybe even around the corner.

But that may provoke a second layer of skepticism: even if it’s possible, is it actually desirable?

After all, in nature and medicine, there’s rarely a free lunch. I’ll absolutely address that concern, along with the limitations of the data, as we move through this scientific story together.

A massive study was just published in Nature, one of the world’s top scientific journals, and when I finished reading it, I was left a bit stunned.

It felt like the paper itself had just walked out of the room after dropping an intellectual mic.

Here’s the punchline:

The thymus—a largely overlooked organ that sits behind your breastbone, just above your heart—may be one of the most important organs for human longevity. In fact, individuals with healthier thymic function had roughly a 50% lower risk of death.

You read that right: a 50% lower risk of death.

In the world of peptides, few compounds are as hyped or as controversial as BPC-157.

It’s become almost mythical for its supposed ability to accelerate healing across the body: from gastrointestinal disorders like inflammatory bowel disease—which is personally relevant to me—to tendon, ligament, and muscle injuries.

But there’s tension here, both scientifically and culturally.

On one side, you have people actually using this compound and reporting remarkable recoveries. Perhaps the most famous example is podcaster Joe Rogan, who has spoken emphatically about how BPC-157 helped him recover from injuries that should have sidelined him.

On the other side, there’s significant pushback from the scientific establishment. In an interview for STAT News, Dr. Flynn McGuire at the University of Utah, for example, said: “The amount of hype to evidence is so skewed, it’s crazy,” and that BPC-157 “Should not be used by humans.”

You can increase your attractiveness to the opposite sex with light.

I know that sounds insane.

It sounds far-fetched. Honestly, that was my reaction too — until I started digging into the data we’re about to break down today.

I’m going to walk you through something that is both deeply surprising and surprisingly well-supported—how exposure to specific wavelengths of light can:

Increase testosterone in men

A massive new paper just dropped in the New England Journal of Medicine days ago on gene therapy for lowering LDL cholesterol.

And it’s breaking headlines.

Now, I realize that sentence, and the associated headlines, are going to provoke two polar-opposite reactions.

On one hand, we have those pronouncing: “We are curing heart disease with one shot!”

On the other, we have those warning: “This is ridiculous. Why would you lower LDL cholesterol with gene therapy? This is pure idiocy.”

As an MD PhD who literally wrote his thesis on neurodegenerative disease—and as someone who carries not one but two copies of the major risk gene variant for Alzheimer’s (ApoE4/4)—you can imagine I’m highly motivated to build a routine that protects my brain until the day I die.

Now, forgive the authoritative opening tone, but I want to get you laser focused on what this letter is going to be about: This is a high-yield synthesis of my supplement and medication protocol for Alzheimer’s prevention.

Summarize what I do to protect my brain and why in a manner that is as concise as possibly while maintaining nuance.

Throughout, I’ll back every statement with links out to deep dives from our archives for those who want to scrutinize the mechanisms and evidence behind each decision.

No fluff. No hedging. Let’s get straight to it.

The FDA recently approved a peptide for a rare mitochondrial disease.

But that’s not the interesting part.

What is interesting is that this same molecule might have implications for some of the most common and burdensome chronic diseases on the planet, from heart disease to diabetes and even to Alzheimer’s and Parkinson’s disease.

This is certainly a peptide I might consider including in my health routine.

But not before first diving into the scientific literature. And when I did, I was struck by genuine optimism.

Last year, I read a paper last year and immediately thought, “this can’t be right.”

It was a human controlled study published in Nature Metabolism that found people who ate less protein burned dramatically more calories—without any meaningful muscle loss.

So, I return to, “this has to be wrong. I just has to be wrong!”

But, I was curious. So, I decided to test it on myself.

And it wasn’t wrong. I was.

I’ve always been fascinated by superheroes—especially the transformations where ordinary people become extraordinary in an instant.

Think Spider-Man bitten by a radioactive spider, or Captain America infused with the super-soldier serum.

Of course, these stories are fantasy.

But they capture something deeper in the human imagination than simple childhood wonder. They tap into a timeless desire: the urge to engineer ourselves into something greater. Stronger. Smarter. Healthier. Maybe even morally better.

Some people wrinkle their noses at that idea. They say it’s “playing God.”

My heart should be riddled with cardiovascular plaque.

I should be having heart attacks like rabbits have babies.

For most of the last seven years, my total cholesterol has hovered around 700 mg/dL. I also have a history of inflammatory disease (ulcerative colitis), my Lp(a) is 194 nmol/L, and my father had a cardiovascular event in his 40s.

In other words, things should not be looking great for me.

And yet, what I’ve found is the opposite: my heart is perfectly clean.