Clean

Clean Plot Summary

Introduction

Five years ago, I stopped showering. At least, by most modern definitions of the word. I still get my hair wet occasionally, but I quit shampooing or conditioning, or using soap, except on my hands. I also gave up other personal care products like exfoliants, moisturizers, and deodorants that I had always associated with being clean. This seemingly radical experiment taught me how much our perception of cleanliness is socially constructed rather than scientifically grounded. Throughout human history, our relationship with cleanliness has evolved dramatically. From ancient ritual purification to the modern trillion-dollar skin care industry, our ideas about what it means to be "clean" reflect deeper cultural values and scientific understanding. Today, emerging research on the skin microbiome—the ecosystem of trillions of microbes living on our skin—suggests we may be dramatically overthinking and overcomplicating skin care. This science reveals that skin is not just a barrier but an interface between our bodies and the natural world, with our microbes acting as both part of us and separate from us. Understanding this complexity could transform how we think about hygiene, products we use daily, and ultimately our relationship with the natural world.

Chapter 1: The Living Ecosystem on Your Skin

Your skin is much more than just a wrapper for your organs—it's your body's largest organ and home to a vibrant ecosystem of life. Covering approximately twenty square feet, skin contains a billion bacteria per square centimeter, with hundreds of different species living in delicate balance. These microbes aren't just passive passengers; they're active participants in your health, influencing everything from immune function to how you smell. The human skin consists of three main layers. The bottom layer contains fat and connective tissue. The middle layer, the dermis, contains collagen and elastin that give skin its strength and elasticity—this is the layer that becomes leather when animal skin is processed. The outermost layer, the epidermis, is paper-thin yet remarkably complex, containing keratinocytes, immune cells, nerve fibers, and melanin-producing cells that determine skin color. What makes skin truly fascinating is how it constantly regenerates. The epidermis completely replaces itself approximately every month as stem cells in the basal layer produce new cells that gradually move upward, flattening and dying as they reach the surface. This natural exfoliation happens without any need for scrubs or chemical peels—your skin has been perfecting this process for millions of years. The various glands in your skin secrete oils and other compounds that serve crucial functions. Sebaceous glands produce sebum that lubricates and waterproofs skin, preventing cracking and dehydration. Eccrine sweat glands cool the body through evaporation, while apocrine glands in the armpits and groin develop during puberty and contribute to body odor when their secretions interact with skin bacteria. For most of modern history, we've viewed these bacteria as enemies to be eliminated. However, new research suggests these microbes play essential protective roles. Some bacteria produce antimicrobial compounds that fight off harmful organisms. Others break down our natural oils into molecules that maintain skin's slightly acidic pH, creating what scientists call the "acid mantle" that helps defend against pathogens. Even face mites (Demodex), microscopic arachnids living in our pores that everyone has, may serve beneficial functions like consuming dead skin cells—nature's original exfoliants. Understanding skin as an ecosystem rather than a surface to be sterilized has profound implications. When we over-clean, we disrupt this delicate balance, potentially contributing to conditions like eczema, acne, and even systemic immune disorders. The emerging science suggests that sometimes, doing less to our skin might actually result in better skin health.

Chapter 2: The Evolution of Cleanliness

The history of human cleanliness reveals a fascinating journey shaped more by cultural and spiritual beliefs than by health concerns. For most of human existence, cleaning rituals were primarily about spiritual purification rather than physical hygiene. Ancient Aztecs cut enormous pools into mountainsides for ritualistic cleansing, invoking the water goddess Chalchiuhtlicue. Egyptian priests performed elaborate washing ceremonies to prepare the dead for the afterlife. These practices were about cleansing the spirit, not killing germs—a concept that wouldn't exist for millennia. Ancient Romans elevated bathing to an art form with their elaborate public baths, but even these weren't primarily about hygiene. The baths functioned as social centers where citizens of all classes communed in caldaria (hot pools), tepidaria (lukewarm pools), and frigidaria (cold pools). The water wasn't particularly clean—with healthy and sick bathers sharing the same pools—but the experience was about leisure and social bonding. Early Christianity, however, began to view such bodily indulgence with suspicion. Saint Jerome declared, "He that is once washed in Christ needeth not wash again," setting the stage for what historian Katherine Ashenburg calls "a thousand years without a bath." This religious skepticism of bathing reached its peak during the Black Death in the mid-14th century. When plague swept through Europe killing a third of the population, medical authorities believed that opening pores through bathing might allow disease-causing "miasmas" (bad air) to enter the body. This notion of disease transmission through noxious vapors, while incorrect, would persist for centuries. Not until John Snow traced a London cholera outbreak to a contaminated well in 1854 did the foundations of modern germ theory begin to take shape. The Industrial Revolution and rapid urbanization of the 19th century created new public health challenges. As cities swelled, outbreaks of typhoid, cholera, and other infectious diseases became more common. The emerging understanding that these diseases spread through poor sanitation led to revolutionary changes in urban planning, including sewage systems and clean water supplies. During this period, appearing clean became tied to social status—the working classes became known as "the Great Unwashed," while cleanliness signified respectability and upward mobility. The soap industry played a pivotal role in transforming cleanliness from a spiritual practice to a health imperative. Companies like Lever Brothers (later Unilever) marketed Lifebuoy soap as "The Friend of Health" during the 1918 influenza pandemic, capitalizing on growing fears of invisible germs. Procter & Gamble's Ivory soap, advertised as "99 44/100% pure," blended religious imagery with emerging scientific language. These marketing strategies helped cement the idea that constant cleaning was necessary for health and social acceptance. The evolution of cleanliness reveals how deeply cultural our notions of hygiene are. What began as spiritual ritual transformed into social obligation and eventually a trillion-dollar industry—all before we truly understood the complex relationship between our skin and the microbial world that inhabits it.

Chapter 3: Marketing vs. Science in Skincare

The modern skincare industry exists at a fascinating intersection of science, marketing, and cultural beliefs about cleanliness. What began as simple soap manufacturing has evolved into a trillion-dollar global enterprise selling everything from basic cleansers to "miracle" serums promising to defy aging. However, the gap between marketing claims and scientific evidence remains strikingly wide. The soap industry pioneered many of the marketing tactics still used today. In the late 19th century, companies like Procter & Gamble and Lever Brothers recognized that since most soaps were chemically similar, success depended on branding rather than product innovation. Ivory soap's famous slogan—"99 44/100% pure; it floats"—created a perception of superiority through pseudo-scientific language, despite other soaps being comparably pure. Palmolive invented a fictional connection to Cleopatra, claiming she used palm and olive oils (rather than donkey milk) to maintain her legendary beauty. These narratives established a template for selling skincare products based on storytelling rather than evidence. Today's skincare marketing has evolved but follows similar principles. Terms like "clinically proven," "dermatologist tested," and "medical-grade" lend scientific authority to products with minimal regulatory oversight. At beauty expos and trade shows, indie brands compete to include trendy ingredients like peptides, stem cells, and collagen, often making vague claims about their benefits. Though peptides (short chains of amino acids) and stem cells appear in countless expensive creams, dermatologist Leslie Baumann notes that there's little evidence they penetrate the skin or function as advertised once applied topically. The industry's scientific language often obscures basic facts about how skin works. For example, many products promise to "boost collagen production" or "detoxify" the skin, yet these claims frequently lack substantiation. When collagen is applied topically, its molecules are too large to penetrate the skin barrier. Similarly, the skin doesn't accumulate "toxins" that need special products for removal—the liver and kidneys handle detoxification. Even vitamin C, a legitimate skincare ingredient with antioxidant properties, is often sold in formulations that may not be stable or penetrate effectively, despite premium pricing. At skincare retailer Glossier—a brand valued at over a billion dollars—products are marketed with the slogan "Skin first. Makeup second," suggesting a focus on skin health rather than cosmetic coverage. However, the company's most popular products are essentially variations of standard formulations sold with aspirational messaging about achieving "glowy, dewy skin." The appeal has less to do with scientific innovation than with founder Emily Weiss's carefully cultivated image of effortless beauty and entrepreneurial success. The disconnect between marketing and science creates confusion for consumers trying to make informed choices. When journalist Krithika Varagur published an article called "The Skincare Con" suggesting the industry oversells its benefits, the backlash was fierce—revealing how deeply people have internalized the idea that elaborate skincare routines are necessary. Yet many dermatologists acknowledge that simpler routines with fewer, evidence-based products often yield better results than complex regimens of trendy ingredients. The most concerning aspect of skincare marketing is how rarely the industry is held accountable for its claims. While pharmaceutical companies must prove their products are safe and effective before marketing them, cosmetic companies face minimal regulatory requirements. The FDA cannot recall harmful cosmetic products and lacks authority to review ingredients before they reach consumers. This regulatory gap allows the industry to sell hope in a jar—sometimes at hundreds of dollars per ounce—with little evidence that the products deliver on their promises.

Chapter 4: How Over-Washing Disrupts Skin Balance

Our modern obsession with cleanliness may actually be harming our skin rather than helping it. Dermatologist Sandy Skotnicki regularly sees patients—particularly men—who develop itchy, irritated skin during winter months. When she asks about their showering habits, a pattern emerges: many are showering twice daily with harsh body washes, essentially declaring war on their skin's natural defenses. "As soon as I get them to stop doing that and just tell them to wash their bits, they're totally fine," she explains. By "bits," she means only the areas that actually need daily cleaning: underarms, groin, and feet. Water alone, especially hot water, slowly strips away the natural oils that keep skin moisturized and protected. Add soap—which by definition has a basic pH around 10.3 designed to bind to and remove oils—and you create a perfect storm for disrupting skin's delicate balance. Every time we wash, we temporarily alter the population of microbes living on our skin and disrupt what dermatologists call the "acid mantle," a slightly acidic film on the skin's surface that helps protect against harmful bacteria. This disruption can trigger a frustrating cycle. When we strip away oils with aggressive washing, the sebaceous glands often respond by producing more oil, leading to what feels like oilier skin after washing. This prompts even more aggressive cleaning, creating a self-perpetuating cycle of disruption. For people with a genetic predisposition to conditions like eczema, this over-washing can trigger inflammatory flares characterized by intense itching, redness, and a compromised skin barrier. The skin barrier function is particularly important and easily damaged. The outermost layer of the epidermis forms a semi-permeable barrier that keeps moisture in and potential irritants and pathogens out. When this barrier is compromised through over-washing or harsh products, it allows greater penetration of potential allergens and irritants. Research now suggests this barrier disruption may play a role in what allergists call the "atopic march"—a progressive cascade where eczema in early childhood is followed by food allergies, allergic rhinitis, and asthma later in life. Counterintuitively, doing less to our skin often yields better results. Maya Dusenbery, a journalist who spent years battling severe acne, tried every prescription treatment available—antibiotics, steroids, harsh topicals—with minimal improvement. Desperate after developing rheumatoid arthritis (potentially linked to years of antibiotic use), she radically simplified her routine, eliminating almost all products. "It got much worse before it got better," she recalls, but after two challenging months, her skin stabilized. Many dermatologists now prescribe "product cleanses" or minimalist regimens for patients with persistent skin issues. The microbial perspective helps explain why less can be more. Our skin hosts diverse communities of bacteria that vary by body region—what's normal in your armpit differs from what's normal on your forearm. These microbes compete with one another for resources, creating checks and balances that help prevent any single species from dominating. When we disrupt these communities through excessive washing or antimicrobial products, we may inadvertently create opportunities for problematic microbes to flourish, leading to inflammation and other skin issues.

Chapter 5: The Microbiome and Immune Health

The discovery that humans are covered in trillions of microbes has revolutionized our understanding of health. These microbes—collectively known as the microbiome—aren't just passive hitchhikers; they're active participants in our biology, influencing everything from digestion to mental health. Nowhere is this relationship more intimate than on our skin, where microbes form an invisible ecosystem that helps train and regulate our immune system. Research among farming communities offers compelling evidence of this connection. Epidemiologist Mark Holbreich noticed something striking about Amish populations in Indiana: they had remarkably low rates of allergies and asthma—just 5% compared to 11% in non-farm Swiss children. When researchers compared the Amish to their genetic cousins, the Hutterites (who share similar diets and lifestyles but use more modern farming practices), they found the Amish had four times lower rates of asthma and six times lower rates of allergies. The key difference? Amish children had much greater exposure to farm microbes from birth, as parents carried babies with them during farm chores. Analysis revealed seven times higher levels of microbial endotoxins in Amish house dust compared to Hutterite homes. This phenomenon reflects what scientists now call the "biodiversity hypothesis" (previously known as the "hygiene hypothesis"). As epidemiologist David Strachan first observed in the 1980s, children with multiple siblings had significantly lower rates of allergies—firstborn children were four times more likely to develop allergies than fifth-borns. The theory suggests that early exposure to diverse microbes trains the developing immune system to distinguish between harmless substances and genuine threats. Without this training, the immune system may become hypersensitive, reacting inappropriately to pollen, food proteins, or even the body's own tissues. Modern lifestyles have dramatically reduced our microbial exposures. In wealthy countries, people spend over 90% of their lives indoors, often in spaces treated with antimicrobial products. Antibiotics, while lifesaving, disrupt microbial communities. Cesarean sections, though sometimes medically necessary, mean babies miss exposure to maternal vaginal microbes. High-fiber diets that feed beneficial gut bacteria have been replaced with processed foods. All these changes correlate with rising rates of immune-related conditions—since the 1950s, asthma, food allergies, type 1 diabetes, and eczema have all roughly tripled in developed countries. The relationship between microbes and immunity extends beyond allergies. Researchers have discovered that certain skin bacteria produce compounds that can inhibit inflammation or fight harmful microbes. For example, Staphylococcus epidermidis, commonly found on human skin, produces antimicrobial peptides that can protect against dangerous Staphylococcus aureus infections. Some bacteria may even protect against skin cancer—mice treated with S. epidermidis before UV exposure developed fewer tumors, possibly because the bacteria produce a compound that targets cancerous cells. This doesn't mean all hygiene practices are harmful—targeted hygiene that focuses on interrupting disease transmission through handwashing and food safety remains essential. However, many scientists now advocate for a more balanced approach that distinguishes between beneficial microbial exposures and genuine disease threats. Microbiologist Jack Gilbert suggests, "I need to get my kids to wash their hands after they go to the toilet, just in case there's a viral or bacterial disease passing through the population. But do I need to sterilize every surface in my kitchen every time I cook? No." Understanding the skin microbiome offers a new perspective on cleanliness—one that acknowledges the value of protective exposures while maintaining practices that prevent disease transmission. Rather than viewing all microbes as enemies to be eliminated, we might instead consider how to cultivate diverse, balanced microbial communities that support our health.

Chapter 6: Modern Approaches to Healthy Skin

As scientific understanding of the skin microbiome advances, a revolution in skincare is quietly underway. Traditional approaches focused on eliminating bacteria through antimicrobial soaps and aggressive cleansing are giving way to more nuanced strategies that recognize the vital role of microbial balance in skin health. This shift represents perhaps the most significant change in hygiene practices since the advent of germ theory over a century ago. The concept of "probiotic" skincare—products containing live beneficial bacteria or ingredients that support them—has moved from fringe to mainstream. Companies like AOBiome pioneered this approach with their Mother Dirt spray containing ammonia-oxidizing bacteria called Nitrosomonas eutropha. These bacteria, according to founder David Whitlock (who famously claims not to have showered in over fifteen years), once naturally populated human skin but have been eliminated by modern cleansers. The spray aims to restore these bacteria, which help break down odor-causing compounds on the skin. Major industry players have taken notice of this paradigm shift. S.C. Johnson & Son Inc. (maker of cleaning products from Windex to Mrs. Meyer's) has licensed AOBiome's consumer product line, while Unilever and Clorox have invested in probiotic brands. Even Dove now markets products claiming to care for "baby skin's microbiome" with "prebiotic moisture." This represents a remarkable pivot for an industry built on eliminating germs. Beyond commercial products, researchers are exploring therapeutic applications of skin microbes. At Jackson Laboratory, scientist Julia Oh is developing engineered probiotic treatments for skin conditions. By modifying Staphylococcus epidermidis to secrete therapeutic proteins, Oh aims to create living treatments for conditions like eczema and rare genetic skin disorders. In early clinical trials, patients with eczema showed improvement after researchers applied Roseomonas mucosa bacteria to their skin—a dramatic departure from traditional steroid and antibiotic treatments. For everyday consumers, the minimalist approach has gained traction. Entrepreneurs like Adina Grigore of S.W. Basics advocate radical simplification: "Leave your skin the fuck alone," she advises. Her products contain just a few recognizable ingredients, contrasting sharply with conventional formulations containing dozens of chemicals. Rachel Winard's company Soapwalla emerged from her personal struggle with lupus-related skin inflammation. After trying countless commercial products without relief, she created a simple deodorant cream that became a cult favorite among those seeking gentler alternatives to conventional products. Dermatologist Julie Segre, who mapped the skin microbiome at the National Institutes of Health, believes the future may lie not in probiotics (adding new microbes) but in prebiotics—compounds that feed and support beneficial microbes already present on the skin. Examples might include ceramides, certain oils, and other ingredients that serve as resources for healthy microbial communities. "I don't understand exactly why it is that people have such a different sense of the microbes that live in their gut than they do about the microbes that live on their skin," Segre notes. "Everyone wants to eat Activia yogurt and colonize themselves with bacteria, and then they want to use Purell." The most practical approach to skin health may be context-dependent. Handwashing remains essential for preventing disease transmission, especially during outbreaks. However, full-body washing with soap may be necessary far less frequently than marketing has led us to believe. Many microbiologists and dermatologists have adopted conservative showering practices, using soap only on specific areas that produce odor (underarms, groin, feet) and avoiding antimicrobial products. As understanding of the microbiome grows, the ideal approach appears to be targeted hygiene rather than the scorched-earth strategy that dominated the 20th century.

Chapter 7: From Chemical Signals to Human Connection

Our bodies constantly communicate through invisible chemical messages that shape our interactions in ways we're only beginning to understand. Each of us emits thousands of volatile organic compounds (VOCs) that form a unique chemical signature—our "volatolome." While humans may not consciously detect these signals the way other animals do, emerging research suggests they influence everything from disease detection to emotional connections between people. This chemical communication becomes strikingly apparent in the work of Claire Guest, who studies how dogs can detect diseases through smell. When Guest's golden retriever Daisy began acting strangely around her, Guest discovered she had breast cancer—a tumor Daisy could apparently smell before medical tests detected it. Scientists now understand that many diseases alter our chemical emissions in distinctive ways. Dogs can be trained to identify malaria, Parkinson's disease, and various cancers with remarkable accuracy by detecting these subtle changes in human scent. The chemical signals we emit likely originate from interactions between our own cells and the microbes living on and in us. When malaria parasites infect human blood, they create distinctive "breath prints" containing compounds that normally wouldn't be present. These include terpenes—chemicals typically produced by plants—that actually attract mosquitoes, potentially helping the parasite spread. Similarly, researchers in Mexico found that the volatolome of women with cervical cancer shows predictable changes that might someday enable early detection through analyzing used menstrual pads. Beyond disease detection, chemical signals play important roles in human connection. While the concept of human "pheromones" marketed in cologne bottles is pseudoscientific, legitimate research shows that exposure to others' airborne compounds can influence physiological responses. Studies of emotional contagion suggest we may unconsciously detect others' stress levels through chemical signals. Physical proximity appears necessary for certain types of connection that cannot be replicated through digital communication—perhaps partly explaining why we feel differently after in-person interactions compared to video calls. Touch amplifies these chemical exchanges while providing its own benefits. Research by developmental psychologist Tiffany Field has shown that regular physical contact has profound effects on health, from helping premature babies gain weight to reducing stress hormones in adults. A study by psychologist Sheldon Cohen found that people who received more hugs showed stronger immune responses when exposed to cold viruses. While the mechanism isn't fully understood, one hypothesis is that physical contact facilitates sharing of microbes that help calibrate immune function. Recovery specialist Justin McMillen has incorporated these insights into addiction treatment, developing programs that encourage physical touch and connection among participants. His approach acknowledges how isolation and disrupted prefrontal cortex function can fuel addiction, while meaningful physical connection can help restore brain function and support recovery. "After class you see guys hanging off each other, the social ideas of boundaries kind of drop away," he explains of the program's movement-based activities. The chemical dimension of human connection illuminates why hygiene practices that completely eliminate our natural scents and microbial communities might inadvertently interfere with forms of communication we're only beginning to understand. Just as the word "clean" has evolved from its spiritual origins to include complex social and scientific meanings, our understanding of human connection is expanding to include the invisible chemical conversations happening constantly between our bodies. Perhaps the most balanced approach to modern hygiene involves recognizing that we are not isolated individuals but interconnected participants in a vast biological conversation—one where our microbes play a crucial mediating role.

Summary

Our modern obsession with cleanliness represents a profound cultural shift that has occurred over just a few generations. What began as spiritual purification rituals across ancient civilizations transformed into elaborate hygiene practices driven by the soap industry's marketing genius. Companies like Procter & Gamble and Lever Brothers didn't just sell soap—they sold new standards of acceptability that redefined what it means to be clean, leveraging fears about disease and social rejection. Today, we've reached an inflection point where emerging science challenges these deeply ingrained beliefs about cleanliness. The discovery that our skin hosts trillions of beneficial microbes fundamentally changes how we should think about hygiene. Rather than viewing our skin as a barrier to be sterilized, we might consider it an interface that connects us to the world around us. The microbes living on our skin represent extensions of ourselves—influencing our immune systems, protecting against pathogens, and potentially even facilitating chemical communication between people. Finding balance means distinguishing between hygiene practices that prevent disease transmission (like handwashing) and those that unnecessarily disrupt microbial communities we've evolved alongside for millennia. As we face growing epidemics of immune-related conditions, perhaps the path forward involves not just more sophisticated products, but a return to simpler practices that honor our biological complexity and our place within larger ecosystems.

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James Hamblin

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