Book summary “The penis book”: summary

Introduction

You likely carry silent anxieties about your body, size, and sexual performance. Modern culture bombards you with unrealistic standards and myths that generate needless worry. Aaron Spitz wrote The Penis Book to replace this confusion with clear urological science.

An erection is a hydraulic and mechanical feat that requires optimal vascular health, balanced hormones, and structural integrity to function properly.

The book explores male anatomy, size realities, and the neurological impact of modern pornography. You will learn how erectile dysfunction acts as an early warning for heart disease and how to navigate advanced medical treatments. The text concludes with lifestyle strategies to protect your vascular health and testosterone levels.

• How do erections actually work under the surface?
• Why do most size concerns stem from optical illusions rather than biology?
• What causes erectile dysfunction, and how can you prevent it?
• Which treatments truly work when standard options fail?

1. Anatomy and Erection Mechanics

An erection operates through a hydraulic process where blood fills internal cylinders under high pressure.

The shaft contains two corpora cavernosum cylinders wrapped in the tough, flexible tunica albuginea. A third cylinder houses the urethra. When blood fills these chambers, they expand by 2 to 5 times their original volume and pinch off draining veins. Ischiocavernosus muscles squeeze the base to create high rigidity. The tunica albuginea contains 5 percent elastic fibers interwoven in collagen. Men notice they are either showers, who possess a longer flaccid size, or growers, whose size increases dramatically during arousal.

Nitric oxide acts as the essential molecular fuel that relaxes smooth muscles to allow blood flow into the penis, while erection pills block the enzyme that breaks it down. Parasympathetic nerve endings and endothelial cells release nitric oxide. This gas triggers a chain reaction that removes calcium from smooth muscle cells, causing them to relax and open up spongy cavities. Phosphodiesterase enzymes normally shut this off, but drugs like sildenafil block that enzyme to keep the erection going. Researchers named nitric oxide the Molecule of the Year in 1992 and awarded the Nobel Prize to its discoverers in 1998.

Adrenaline and sympathetic nerves act as the braking system that constricts blood flow and kills erections during stress or perceived danger. Sympathetic nerves release adrenaline and noradrenaline into artery walls. These chemicals clamp down on smaller blood vessels in non-vital parts like the penis to prioritize survival organs during a threat. The nervous system cannot distinguish between real danger and ordinary performance anxiety.

Ejaculation and Semen Composition

Semen is a specialized fluid cocktail where actual sperm make up a tiny fraction, while the majority of the volume comes from the seminal vesicles and the prostate. Sperm account for 10 percent or less of semen volume, having traveled from the testicles through the epididymis and the vas deferens. Seminal vesicles contribute about 70 percent of the volume with a nutrient-rich fluid, and the prostate adds enzymes that temporarily solidify and then liquefy the semen. The testicles produce 375 million new sperm a day, and semen takes 15 to 30 minutes to liquefy. Semen consists of 90 percent water and contains fructose, proteins, vitamins, and amines like cadaverine and putrescine which protect sperm from vaginal acidity. Fruits rich in fructose may slightly sweeten flavor, whereas meats, dairy, protein powders, and dehydration make it saltier or more bitter.

Premature ejaculation can be treated behaviorally through targeted pelvic exercises and stop-start techniques, or medically via topical nerve-blocking sprays and daily SSRIs. Rapid ejaculation is often linked to an underactive serotonin response or anxiety-driven adrenaline release. The condition affects almost 1-in-4 men, while the average duration of intercourse is about 5 and a half minutes.

You can use specific behavioral and physical methods to manage climax timing:

• Clench the muscles around your anus and urethra that you would clench when trying to stop yourself from urinating or defecating.
• Do bursts of quick squeezes in succession and longer holds with more time in between.
• Stimulate your penis with a partner to make it hard and close to coming, then stop, cool down, and try again.

Medical options include lidocaine-based numbing sprays like Promescent and low-dose selective serotonin reuptake inhibitors. A study using Kegel exercises and electrical stimulation showed an average duration increase from 39 seconds to an average of 146 seconds. Some men use a 120 milligram double dose of Sudafed as an occasional workaround.

Men can experience normal sexual orgasms without ejaculation if sympathetic nerves are damaged, or can experience reflex ejaculation without climax if brain pathways are interrupted. Nerve damage from surgery, diabetes, or multiple sclerosis can cause retrograde ejaculation or stop fluid-producing structures from squeezing. This leaves orgasm sensation intact if sensory skin nerves remain functional. Conversely, high spinal cord injuries above the 10th vertebra level can trigger reflex erections and ejaculation without conscious sensation or orgasm.

2. Size Reality and Enhancements

Most men possess a normal size, while optical obstructions and industry myths create unwarranted anxiety.

The Reality of Size

The vast majority of men possess a completely normal penis size, but optical obstruction from abdominal fat and unrealistic media portrayals create widespread anxiety. You often misjudge your size due to an obstructed self-view caused by abdominal fat or a webbed scrotum.

David Veale and colleagues at King’s College London reviewed scientifically sound studies to establish clinical averages for soft and erect measurements. According to this research, the average erect penis length is just over 13 centimeters with an average erect girth of about 11 centimeters.

• 9 centimeters: average soft length give or take 1.5 centimeters
• 13 centimeters: average erect length give or take 2 centimeters
• 11 centimeters: average erect girth give or take 1 centimeter
• 5.1 to 5.6 inches: average penis size range
• 2 percent: maximum proportion of men with a penis considered smaller than normal

Differences between growers and showers stem from the molecular composition of the erectile tissue cylinders. The penis contains a weave of tough collagen and elastic elastin. Growers possess a higher proportion of elastin and less collagen, making them smaller at rest and more sensitive to cold temperatures, while showers have more collagen and less elastin.

Supplements and Surgical Limits

Many over-the-counter natural sexual enhancement products lack authentic ingredients or are illicitly spiked with pharmaceutical drugs, though specific amino acids and herbal extracts can safely boost nitric oxide. Studies show that about 8 out of 10 erection pills claiming to be natural are spiked with pharmaceutical drugs like Viagra or Cialis. However, legitimate compounds like L-citrulline, Korean red ginseng, pycnogenol, and maca root support erectile function by increasing nitric oxide production to enhance blood flow.

Researchers testing VigRX Plus found significant improvements in erections without pharmaceutical spiking, reporting only mild fever as a side effect.

Mechanical vacuum erection devices and traction extenders serve legitimate medical purposes in rehabilitation and modest tissue stretching but cannot radically transform a normal organ. Vacuum erection devices draw blood into NO-starved tissue and rehabilitate men post-prostate surgery, while traction devices apply continuous spring-loaded tension to create microscopic tissue breaks that stimulate minor length gains over months of consistent use.

In studies on men using penile extenders for 4 hours a day or more over 6 months, length increases ranged from 1 to 2 centimeters.

• Apply the penis traction device with the penis soft, setting extension arms to pull as taught as possible without pain.
• Wear the device for 2 hours, remove for 20 minutes to rest, and replace for 2 more hours.

Surgical penis enlargement relies on optical illusions by cutting the suspensory ligament and carries substantial complication rates and low patient satisfaction. Suspensory ligament release drops the flaccid penis lower to look slightly longer, but leaves the erect organ wobbly or pointing downward and risks severe scarring that pulls the penis back inward. Girth augmentation via fat or dermal fillers similarly risks lumpy deformation and chronic scarring.

Patient satisfaction for suspensory ligament cutting surgery is reported below 30 percent, with many requiring reoperation.

3. Culture and Pornography Impact

Excessive pornography consumption desensitizes brain reward centers and drives rising rates of young male erectile dysfunction.

Professional pornography is an extreme, highly staged form of entertainment that bears little resemblance to real human intimacy. A typical 20-minute porn clip requires 4 to 8 hours of grueling filming, endurance drugs, makeup, and stunt doubles.

Male porn stars have had sex with an average of nearly 150 partners, compared to about 6 partners for average civilians.

Frequent porn viewing hijacks dopamine pathways through constant novelty seeking in the dorsal anterior cingulate cortex, shrinking brain structures related to romantic love. This leads to unrealistic performance expectations, partner dissatisfaction, and a sharp increase in psychological erectile dysfunction in young, healthy men. While historically only 5 percent of men under 40 experienced erectile dysfunction, up to 1 in 3 young men now suffer from it following the rise of streaming pornography.

Circumcision and Grooming

Circumcision is one of the oldest and most globally common surgical procedures, performed on roughly one in three males worldwide. The procedure dates back over 15,000 years, originating in regions like Egypt, and holds deep religious and cultural significance in Judaism and Islam. Today, acceptance and prevalence vary drastically by country and ethnicity, with high rates in nations like the US, Israel, and South Korea, and very low rates across Europe and Latin America. In the biblical Book of Genesis, circumcision was utilized by Jacob's sons as a military plot against Prince Shechem and his people.

Newborn circumcision is a brief procedure typically utilizing specialized clamps, whereas older boys and adults require local anesthesia and stitches. Infant procedures take about ten minutes and utilize tools such as the Gomco clamp, Plastibell device, or Mogen clamp. Older patients require a more complex surgical approach with a longer healing window of three to four weeks.

Proper hygiene and careful execution are essential for manscaping to prevent skin irritation, ingrown hairs, and bacterial infections in the groin area. Because the male groin is warm and moist, it easily harbors bacteria, yeast, and fungi.

You can follow a precise grooming routine to protect the skin:

• Use trimmers to shorten the pubic hair before shaving
• Exfoliate Rumpleforeskin gently
• Take a hot shower to open pores, soften skin, and remove dirt or oils
• Use preshave oil to lift hair up, add hydration, and prevent irritation
• Avoid products that cause ingrown hairs such as fragrances, mineral oil, cooling agents, or citrus
• Shave, wax, or epilate using a sharp razor and shave gel
• Apply soothing balms like shea butter, cocoa butter, and aloe vera for nicks
• Finish with postshave moisturizer to reduce skin irritation and itchiness

4. Causes of Erectile Dysfunction

Erectile dysfunction is largely a physical vascular problem that serves as an early warning sign for cardiovascular disease.

The most durable form of erectile health involves protecting your vascular endothelium and managing medical conditions.

Medical Causes

Erectile dysfunction is defined as the inability to keep the penis hard enough and long enough for satisfying sex, and it can be measured using a specific five-question medical questionnaire. You can assess your symptoms by reviewing a scale where questions are scored from 1 to 5 based on the past six months, covering confidence, penetration hardness, maintenance during intercourse, completion difficulty, and satisfaction. A total score of 22 to 25 is normal, 12 to 21 is mild ED, 12 to 16 is mild to moderate, 8 to 11 is moderate, and 5 to 7 is severe.

• Rate your confidence from 1 (very low) to 5 (very high) that you could get and keep an erection.
• Rate how often your erections were hard enough for penetration from 1 (almost never) to 5 (almost always/always).
• Rate how often you were able to maintain your erection during intercourse from 1 (almost never) to 5 (almost always/always).
• Rate how difficult it was to maintain your erection to completion from 1 (extremely difficult) to 5 (not difficult).
• Rate how often sexual intercourse was satisfactory from 1 (almost never) to 5 (almost always/always).

Aging is the most common incurable cause of erectile dysfunction, driven by arterial narrowing, free radical oxidation, endothelial dysfunction, and declining testosterone. About 40 percent of men have some degree of erection problem by age 40, scaling up by 10 percent each decade so that 50 percent have problems at age 50, 60 percent at age 60, and so on. Penile arteries are only 1 millimeter in diameter, making them narrower than coronary or carotid arteries.

Erectile dysfunction is frequently the earliest warning sign of cardiovascular disease, with more than 40 percent of affected men eventually experiencing a heart attack or stroke. Men with ED have a greater than 50 percent chance of developing cardiovascular disease. A long-term study at the Cleveland Clinic demonstrated that the most severe cardiovascular cripples became healthy and lived for decades if they adhered to a plant-based diet.

• Adhere to a primarily plant-based diet with minimal simple carbohydrates, minimal simple starches, minimal animal products, and minimal oils.
• Engage in regular exercise.

Diabetes damages the penis by causing endothelial dysfunction, destroying small blood vessels and nerve endings, and impairing the biological signaling required for erections and ejaculation. Uncontrolled blood sugar ruins the ability of blood vessels to release normal levels of nitric oxide and damages capillaries that supply oxygen to nerves. Every percentage point increase in hemoglobin A1c causes a 55 percent increase in the chance of having ED.

• Keep fasting sugar level close to 100 milligrams per deciliter.
• Keep hemoglobin A1c under 5.7 percent.
• Boost intake of fresh vegetables and cut out simple carbohydrates and sugary sodas.

Penis Pills and Troubleshooting

Prescription penis pills treat erectile dysfunction by inhibiting phosphodiesterase type 5, the natural chemical enzyme that breaks down nitric oxide and terminates erections. All ED pills block this enzyme, allowing nitric oxide to accumulate and maintaining bloodflow. Viagra starts working in 30 minutes to 1 hour and lasts for 4 hours, while Cialis lasts up to 36 hours.

During a clinical trial for an angina medication in the early 1990s, clinical trial patients revolted when researchers tried to stop the trial, revealing that the drug caused better erections as a side effect and leading to the creation of Viagra.

While penis pills are generally safe when taken alone, combining them with nitroglycerine or recreational amyl nitrite poppers causes a lethal drop in blood pressure.

• Check with a cardiologist or doctor before taking ED pills if you have a fragile heart or recent heart attack.
• Never combine any penis pill with nitroglycerine, medications containing nitroglycerine, or amyl nitrite poppers.

When initial doses of penis pills fail, the causes are often performance anxiety, underdosing, food interactions like fatty meals, or alcohol interference rather than permanent treatment failure.

• Take Viagra or sildenafil an hour before meals or 2 hours after meals to avoid absorption interference from food.
• Give pills multiple tries to reduce anxiety-driven adrenaline release.

5. Advanced ED Treatments

When oral pills fail, second-line and third-line therapies provide mechanical and chemical alternatives to restore sexual function.

Second-line treatments bypass the brain and normal nerve signaling to produce an erection for the 35 percent of men for whom the pills won't work. These options include self-injections into the penis, urethral suppositories, and vacuum erection devices.

Injections and Pumps

Penile injections use potent vasodilators like alprostadil, bimix, trimix, and quadmix to force blood vessels to open up without requiring nerve signals. Alprostadil helps about 70 percent of patients in general and 90 percent of those who have failed to improve with pills. Compounded formulas degrade over time, and 2 months later they are about 30 percent less potent.

You can administer these treatments safely with specific steps:

• use sterile technique and fresh needles and syringes each time;
• hold pressure on your penis for a couple of minutes after injection;
• wait another day if the dose isn't strong enough before increasing.

An erection lasting longer than four hours from powerful injections is a dangerous medical emergency called priapism that requires immediate countermeasures.

• Try to climax to release adrenaline.
• Hit the treadmill or climb some stairs for exercise.
• Take two immediate-release 60-milligram over-the-counter Sudafed tablets.
• Use a couple of squirts of Neo-Synephrine nasal spray.
• Take 5 milligrams of prescription Terbutaline, wait 15 minutes, and take another 5 milligrams if still hard.

MUSE delivers alprostadil directly into the urethra as a pellet alternative for men who want to avoid needles. You push the pellet into the urethra using the plunger and roll the penis back and forth between your hands like trying to spark a campfire with a stick.

The vacuum erection device overrides nerve and artery failures mechanically by pulling blood into the penis using negative pressure.

• Place transparent plastic cylinder over the penis.
• Pump air out to create a vacuum and draw blood into the penis.
• Slip elastic constriction band onto the base of the penis to prevent drainage.
• Rinse and repeat after use.

The band must not be left on for more than 30 minutes to prevent oxygen deprivation. Prostate cancer surgery or radiation damages nearby nerves that trigger erections, causing rapid tissue fibrosis and shortening under the principle of use-it-or-lose-it. You can perform penis rehab to prevent shrinkage:

• Use the vacuum pump for 5 or 10 minutes a day without the constriction band for tissue rehab.
• Take daily Cialis or perform injections 3 to 4 days a week on alternating days after surgery.

Surgical Implants

Penile implant surgery is the definitive third-line treatment for erectile dysfunction, replacing the blood-filling chambers with mechanical prosthetics. Dr. Brantley Scott introduced the multi-component inflatable system in 1973, which features a less than 2 percent per year mechanical failure rate and about 2 percent risk of infection. You can use penis prehab before surgery:

• Use the vacuum constriction device for several minutes a day for several weeks before surgery.

You must pump up the implant at least once a day for the first 3 months to prevent the surrounding capsule from restricting expansion.

6. Testosterone and Vascular Health

Testosterone regulates muscle and bone strength, sexual desire, and mood. Testosterone is essential for male vitality, sexual performance, and overall health, but artificial supplementation should always be managed by a qualified physician to avoid severe side effects.

Low levels correlate with obesity, diabetes, and heart disease. Seventy percent of men with low T are obese, and at least half of men with diabetes have low T. Self-medicating or using unprescribed boosters can lead to sterility, erectile dysfunction, blood clots, and cancer.

Diagnosing low testosterone involves screening questionnaires and blood tests that account for varying time cycles and binding proteins. The ADAM questionnaire helps identify potential androgen deficiency. Blood tests must measure both total testosterone and free testosterone because sex hormone binding globulin and albumin can trap testosterone molecules, rendering them inactive. Less than 200 ng/dl total T with symptoms indicates low levels, while normal T ranges from 400 to 1000 ng/dl.

Low testosterone can stem from lifestyle choices, direct testicular damage, genetic conditions, pituitary issues, and the natural aging process. Poor diet, alcohol, and drugs deplete testosterone. One in 100,000 men is struck by testicular cancer, and about half of men over 60 have low T. Excess fat converts testosterone into estrogen via aromatization, which subsequently suppresses the pituitary gland's output of luteinizing hormone.

Various delivery methods can successfully restore testosterone levels, each carrying distinct advantages, absorption issues, and side effects. Fifteen percent of men cannot absorb testosterone well through their skin.

You must follow proper medical protocols when treating low levels:

• Consult a knowledgeable physician to get prescriptions and proper dosages for testosterone.
• Undergo regular blood level monitoring and physical examinations.
• Answer the ADAM screening questionnaire for symptoms like low libido, fatigue, or strength loss.
• Check testosterone levels at least twice and always in the morning.
• Apply skin-based testosterone formulas daily as part of grooming.
• Cover application areas with a T-shirt and wash thoroughly before intimate contact.
• Monitor red blood cell production regularly to prevent sludgy blood.

Nutrition and Endothelial Health

Nitric oxide is the critical molecule that relaxes vascular smooth muscle and fills the spongy chambers of the penis to create erections. Nitric oxide is the critical molecule that relaxes vascular smooth muscle and fills the spongy chambers of the penis to create erections.

The vascular endothelium lining the blood vessels produces nitric oxide, which stretches muscle linings and prevents tissue aging. Dietary nitrates from whole plant sources convert into nitrites and subsequently nitric oxide via oral bacteria and stomach acid. Over 8,000 different polyphenol molecules have been identified, and 6,000 polyphenols are categorized as flavonoids.

Processed carbohydrates and added sugars trigger insulin surges, store excess fat, release free radicals, and destroy nitric oxide production. When the food industry removed fat from products, they substituted simple carbohydrates and sugars to maintain flavor. This shift generated systemic inflammation, tissue oxidation, and metabolic syndrome, severely impairing erectile function. Low-fat, low-calorie foods have up to twice as much sugar as regular versions, and one in three men in the United States will develop diabetes.

Excessive consumption of animal proteins and hidden food additives like phosphates promotes vascular disease, arterial calcification, and erectile dysfunction. High amounts of animal protein mirror the blood vessel damage caused by simple carbohydrates and fats. Furthermore, food additives such as phosphates transform smooth muscle cells in arteries into calcified bone cells. Animal products make up only about 5 to 10 percent of the total diet in rural Asian Blue Zones.

You can protect your endothelium through targeted dietary habits:

• Consume whole powerhouse vegetables like beets, lettuce, arugula, and spinach for nitrates.
• Thoroughly chew food to let oral bacteria on the tongue convert nitrates into nitrites.
• Avoid processed foods, particularly light or low-fat versions containing added sugars.
• Eliminate white flour products, white rice, soft drinks, and obviously sweetened desserts.
• Check food labels for hidden sugar names like anhydrous dextrose, maltose, and high-fructose corn syrup.
• Think twice before eating foods inside a wrapper, box, or can that contain hidden phosphates.
• Adopt a 90/10 approach by keeping meals roughly 90 percent plant-based.

7. The Five-Step Prescription

You can optimize erectile health through a targeted regimen involving diet, exercise, digital detox, and sufficient sleep.

Inactivity dramatically increases the risk of erection problems, while regular vigorous exercise protects and even reverses vascular dysfunction. Sedentary habits allow inflammatory molecules to accumulate in the bloodstream, damaging the endothelial lining and depleting nitric oxide. Inactive men face more than 10 times the risk of erection problems compared to active guys. Tolerably fit guys face 4 times the risk of problems compared to good fitness levels. Traditional bicycle seats can compress critical nerves and arteries, significantly reducing blood flow and potentially causing erectile dysfunction in avid riders. Up to 70 percent of competitive cyclists complain of numbness, and a 70 percent drop in blood flow occurs during bicycle riding. Up to 24 percent of competitive riders develop erectile dysfunction, while 13 percent of amateur riders experience trouble.

Sexercise and Kegels

Strengthening the pelvic floor muscles through targeted squeezes enhances erection rigidity, prevents venous leakage, and improves ejaculatory control. Three months of Kegel exercises provide benefits equivalent to Viagra in some men.

• Squeeze the muscles used to stop urination or a bowel movement without using abdominal or gluteal muscles.
• Hold the squeeze for 10 seconds, then release slowly for 10 seconds.
• Perform three to five sets of 10 repetitions each over the course of the day.
• Practice short 1- to 2-second squeezes more frequently.
• Perform exercises first standing, then sitting, then lying on your back, then on all fours.

Detox and Snooze

High-volume streaming pornography consumption desensitizes brain reward centers, shrinking specific neural structures and causing epidemic rates of erectile dysfunction in young men. One-third of men under 40 have ED and low sexual desire.

Sufficient sleep is mandatory for maintaining optimal testosterone surges, healthy nerve function, and vascular integrity necessary for sexual health. Sleeping 5 hours or less drops testosterone by an amount equivalent to aging 10 to 15 years. At least 15 percent of the American workforce gets under 5 hours of sleep a night.

10 Key Ideas

1. An erection operates through a hydraulic process where blood fills internal cylinders under high pressure, while adrenaline and sympathetic nerves act as a braking system that constricts blood flow during stress.
2. Nitric oxide acts as the essential molecular fuel that relaxes smooth muscles to allow blood flow into the penis, a process that can be protected through a plant-based diet rich in whole powerhouse vegetables like beets, lettuce, arugula, and spinach.
3. The vast majority of men possess a completely normal penis size, but optical obstruction from abdominal fat and unrealistic media portrayals create widespread anxiety.
4. Frequent professional pornography viewing hijacks dopamine pathways and leads to unrealistic performance expectations, contributing to a sharp increase in psychological erectile dysfunction in young men.
5. Erectile dysfunction is frequently the earliest warning sign of cardiovascular disease, with more than 40 percent of affected men eventually experiencing a heart attack or stroke.
6. Prescription penis pills treat erectile dysfunction by inhibiting phosphodiesterase type 5, the natural chemical enzyme that breaks down nitric oxide and terminates erections.
7. Penile self-injections use potent vasodilators like alprostadil, bimix, trimix, and quadmix to force blood vessels to open up, requiring sterile technique and strict awareness of dangerous complications like priapism.
8. Testosterone is essential for male vitality, sexual performance, and overall health, but artificial supplementation and diagnosis must be managed by a qualified physician using blood tests and screening questionnaires to avoid severe side effects.
9. Strengthening the pelvic floor muscles through targeted Kegel squeezes enhances erection rigidity, prevents venous leakage, and improves ejaculatory control with benefits equivalent to Viagra in some men.
10. Sufficient sleep is mandatory for maintaining optimal testosterone surges, healthy nerve function, and vascular integrity necessary for sexual health, as sleeping five hours or less drops testosterone by an amount equivalent to aging ten to fifteen years.