“Your penis is the canary in the coal mine for your overall health.”
Let’s be honest. Most guys don’t think about their penis in terms of HEALTH. They think about it in terms of size, performance, and whether everything is “working” correctly. That’s about it.
But Dr. Aaron Spitz — a urologist who has spent decades examining, diagnosing, and treating thousands of penises — wrote this book to change that. And honestly, it’s one of the most informative and entertaining health books I’ve read.
Yes, entertaining. About penises. Stay with me.
The Canary in the Coal Mine
The single most important idea in this book is that your penis is a direct indicator of your overall health. It’s not just a reproductive organ — it’s a diagnostic tool.
Think about it. Erectile dysfunction is one of the earliest warning signs of cardiovascular disease. The blood vessels in the penis are SMALLER than the ones in your heart. So when blood flow starts to decline due to clogged arteries, poor diet, or lack of exercise, the penis is the FIRST place you notice it.
By the time you have a heart attack, your penis has been trying to warn you for years.
Most men don’t go to the doctor until something is seriously wrong. But if your erections are weaker than they used to be, that’s not just an “age thing” — that’s your body telling you something is going on with your vascular system.
Size, Myths, and Insecurities
Of course, Dr. Spitz addresses the elephant in the room. Size.
The book breaks down the actual data. The average erect penis is about 5.1 to 5.5 inches. That’s it. The vast majority of men fall within a relatively narrow range, and the obsession with size is largely driven by pornography, which presents a wildly distorted picture of reality.
Dr. Spitz also dismantles the myths. Pills, pumps, and supplements that claim to increase size? They don’t work. Surgery? Risky, with minimal results and potential complications. The only thing that actually makes a visible difference? Losing belly fat. The more abdominal fat you carry, the more of your penis is buried underneath it. Lose the gut, and you “gain” length that was always there.
So the best penis enlargement strategy is literally just getting in shape. Go figure.
Blood Flow Is Everything
If there’s one theme that runs through the entire book, it’s blood flow.
An erection is fundamentally a hydraulic event. Blood flows in, gets trapped, and the result is rigidity. Anything that impairs blood flow — smoking, high cholesterol, diabetes, obesity, stress, lack of exercise — directly impairs erectile function.
This is why young guys in their 20s who smoke, eat garbage, and never exercise can start experiencing problems that they assume are “psychological.” It’s not in your head. It’s in your arteries.
Dr. Spitz emphasizes that the same lifestyle changes that protect your heart also protect your penis:
1. Exercise regularly — cardio is king for blood flow.
2. Eat a plant-heavy diet — the book is very pro-Mediterranean diet and even leans toward plant-based eating for optimal vascular health.
3. Don’t smoke — smoking is one of the single worst things you can do for erectile function.
4. Manage stress — chronic stress and cortisol wreak havoc on testosterone and blood flow.
5. Sleep well — testosterone is produced primarily during sleep. Less sleep = less testosterone = worse performance.
Testosterone and Hormones
The book dives into testosterone in a way that’s actually useful, rather than the usual bro-science you find online.
Testosterone peaks in your late teens and early 20s, then gradually declines about 1% per year after age 30. That’s normal. It’s NOT normal for a guy in his 30s or 40s to have the testosterone levels of a 70-year-old, which is increasingly common due to obesity, poor sleep, and sedentary lifestyles.
Dr. Spitz also covers the controversial topic of testosterone replacement therapy (TRT). While it can be life-changing for men with genuinely low levels, it comes with trade-offs — including potential infertility, since external testosterone signals your body to stop producing its own, which shuts down sperm production.
The takeaway? Fix the lifestyle factors FIRST. Exercise, sleep, diet, and stress management can naturally boost testosterone significantly. TRT should be a last resort, not a shortcut.
STIs, Porn, and Modern Challenges
Dr. Spitz doesn’t shy away from the uncomfortable topics either.
The STI chapter is a sobering reality check. HPV alone infects roughly 80% of sexually active people at some point in their lives. Most never know they have it. Some strains cause cancer. The chapter isn’t designed to scare you — it’s designed to make you informed and responsible.
The book also touches on pornography and its effects on sexual function. While Dr. Spitz isn’t anti-porn in a moralistic sense, he acknowledges the growing clinical evidence that excessive porn consumption can desensitize the brain’s dopamine pathways, leading to difficulty getting aroused with a real partner. This is consistent with what I’ve read in books like Dopamine Nation and Your Brain on Porn — overstimulation leads to a dulled response to normal stimuli.
The Five-Step Plan
The most practical part of the book is Dr. Spitz’s five-step plan for optimal penis health. It’s essentially a holistic health plan disguised as penis advice:
1. Eat for blood flow — more plants, more whole foods, less processed garbage.
2. Move your body — 150 minutes of moderate cardio per week minimum.
3. Sleep 7–8 hours — non-negotiable for testosterone and recovery.
4. Manage stress — meditation, breathing exercises, whatever works for you.
5. See your doctor — get blood work done, check your testosterone, don’t wait until something breaks.
Notice anything? This is the SAME advice that every cardiologist, endocrinologist, and longevity researcher gives. The penis is just the most compelling motivator for men to actually follow through.
Final Thoughts
The Penis Book is surprisingly one of the most practical health books I’ve read. Dr. Spitz writes with humor, zero judgment, and the clinical expertise of someone who has seen EVERYTHING. It’s not awkward or cringe — it’s genuinely informative.
If you’re a guy and you care about your health, your performance, or just understanding how your body actually works, this is a must-read. And if the title makes you uncomfortable, that’s kind of the point — we need to stop treating men’s health like a taboo topic.
The “canary in the coal mine” concept alone is worth the price of admission. Take care of your body, and your body takes care of everything else.
Highly recommended — 5/5
Thanks for reading.
— Leonidas
