One day while I was washing my hands, I looked down at the bar of soap and wondered, what is this soap made of? I thought about it as my hands lathered up, and soon realized I have absolutely no idea.

While there are lots of things I know nothing about, this one concerned me. Every single day, often multiple times each day, I slather this unknown substance all over myself leaving it to be absorbed by the largest organ in my body. So I set off on a mission to figure it out.

My first stop was my local supermarket.

As soon as I walked in, it was clear I was in over my head. There were entire shelves full of soap. Soap in bottles, soap in squares, soap for hands, soap for hair, soap for dishes, soap for dry palms, soap for clothing, even soap for underarms.

But I was determined to get an answer. So I picked up every bar of soap in the store, collected all of their ingredients in a spreadsheet, and tried to make sense of it all.

I found 22 different soaps from 7 different brands, each with an average of 17 ingredients. And that was just the bar soaps. The many shelves of liquid soaps, lotions, shampoos, deodorants, moisturizers, cleaners, and other soap derivatives survived another day without my scrutiny.

Once I reflected on the data, a few things immediately stood out.

First, I still had no idea what soap was made of. Most of the ingredients were chemical compounds I had never heard of.

Second, most soaps were simply different scents added to the same base soap. Dove had 12 different variants, Irish Spring had 3, and Ivory and Olay each had 2. The only soaps that came in one scent were from Pears, Caprina, and Aveeno.

Finally, none of the soaps in the supermarket struck me as extraordinary. They used similar buzzwords, they were all produced by large corporations, and the biggest differentiators seemed to be their colors and scents.

So I went further down the soap rabbit hole in search of answers to a few burning questions:

• What are all the chemicals in soap?
• What did we make soaps from before all these chemicals were invented?
• Why did we switch to modern chemical soaps?
• Why do brands sell so many versions of the same soap?
• What are the side effects of our modern soaps on our health?
• What does an extraordinary soap look like?

What Chemicals Are In Soap?

While analyzing the ingredients in my supermarket soaps, I counted the number of times each ingredient was used, and information about each ingredient. At the bottom of this post I added a table with all 83 ingredients found in the 22 bars of soap I found, along with notes for what each ingredient does and those which are potentially harmful.

As it turns out, most soap ingredients aren’t there to clean your skin. Some are added to simulate certain scents or colors, some are added to extend shelf life, some are there to enhance a soap’s lather, and some of them are just added to stop all the other chemicals from interacting with each other.

But that’s not all.

Among the 83 ingredients I looked into, 6 are known to be toxic or carcinogenic and 29 are known to cause skin irritation or allergies. And those are just two human side effects. Chemicals like Sodium Lauryl Sulfate (found in Pears Transparent Soap) also show evidence of contributing to environmental toxicity. None of the 22 soaps examined were free from chemicals known to be carcinogenic, toxic, or to cause skin irritation or allergies.

These chemicals rarely get banned by regulators, and when they do, it is often decades after there is reason to believe they are dangerous. For example, in 2016 the FDA banned Triclosan - an antibacterial agent - on the grounds that it is linked to hormone cycle disruptions, muscle weakness, and other health and environmental problems. However, Triclosan was introduced in 1972, so it took 44 years of exposure to recognize the problems it was causing.

As depressing as this discovery was, I knew it wasn’t always like this.

Pre-Industrial Soap

While looking into the history of soap, I found Katherine Ashenburg’s book The Dirt on Clean to be a thorough, surprising analysis of soap and cleanliness over the course of human history.

It turns out humans have tried all sorts of strange rituals for cleaning themselves. The Romans rubbed olive oil on their skin and used metal scrapers to scrape off their dirt. For hundreds of years after the plague, French people were so fearful of bathing in water that they avoided it at all costs. Changing outfits was their version of cleaning.

And while some people in Japan, India, and elsewhere had established hygiene routines, there is no historical precedent for our modern obsession with cleaning ourselves head-to-toe every single day. Daily showers, deodorants, hand soaps, shampoos, and lotions are all modern phenomenons that simply didn’t exist until the industrial era.

We’ll get into the pros and cons of that in a moment.

But for most of human history, any time we did use soap, it was made from just two ingredients. Fat and lye. The fat often came from cows or sheep, and lye came from wood ashes and water. That was it.

The combination of fat and lye form molecules with two arms. The first arm is lipophilic (it binds to grease and dirt from your body), and the second arm is hydrophilic (it binds to water). So when you rub soap on your body, the soap molecules attach to your dirt, and when you wash in water, the soap molecule gets washed away along with your dirt.

And despite significant advances in chemistry over the years, soap mostly works the same way today. Which introduces our next question.

Fat-Based vs. Chemical Soaps

Why are there no fat and lye soap bars in supermarkets anymore? And why did we replace them with soaps containing dozens of ingredients that require a chemistry degree to understand?

We already know that most soap chemicals were not added to improve our health, and the function of soap hasn’t really changed, so what did change?

For one, germ theory got traction in the late 1800s. People began learning that germs can cause disease, and began taking preventative measures to wash themselves.

People began internalizing cleanliness as a virtue, and class divides between those who worked in “dirty” manual labor jobs and those in retail or “professional” office settings grew larger.

Smell became a signal for poor hygiene, but since bad smells are not always obvious to smelly people, advertisers capitalized on those insecurities. Companies caused people to believe that the reason they weren’t making friends or getting married was because they smelled.

Listerine even coined the phrase “Often a bridesmaid, but never a bride” to sell more mouthwash in the early 1900s.

But as their marketing engines picked up steam, a problem emerged. Soap makers had high profit margins, but a commoditized product without competitive advantages. This incentivized them to expand beyond fat and lye and design their own proprietary soap formulas, allowing them to make claims that their soaps were unique and better than others.

Why So Many Soap Scents?

But that still doesn’t explain why there are 12 different versions of the same Dove soap bar in my local supermarket. For that, we can thank a man named Howard Moskowitz.

Howard was a market psychologist, and in the 1970s, he became obsessed with an idea about the products that make people happy. As Malcolm Gladwell explained in a 2004 TED talk, Howard changed the way the food industry thinks by introducing the idea of horizontal segmentation.

Howard spent years studying consumer tastes to create the perfect product for brands like Pepsi and Campbell’s Soup, but began to realize this task was a fool’s errand. He felt there was no such thing as a perfect product, rather different kinds of products that suit different kinds of people.

His view was that people naturally cluster around different tastes rather than congregating around a single “optimal” flavor, but this ran counter to the way the food industry worked. At the time, food brands had universal rules for how to treat their customers. Coke had just one product, it was called Coke. Dove and Irish Spring each sold just one soap.

But Howard realized that by averaging everyone’s preferences into a single product, you end up with a product that nobody really loves. If instead, you split up your customers into segments, and designed products specifically for people who want more sugar in their soda, extra chunky tomato sauce, or gingerbread scented soap, you can make those people much happier.

Of course, if you can make your customers happier, you can make more sales. So before long, the skincare industry applied Howard’s discovery to their soap product lines and an endless array of soap scents followed.

And that brings us to today, where not only do we have a scent for every customer, we also have a product for every body part and every skin condition. Our skin works the same way it has for thousands of years, yet the treatments we apply to it have exploded in complexity and frequency. What are the side effects of that?

Modern Hygiene Side Effects

In Dr. Sandy Skotnicki’s book Beyond Soap, she believes that increasing rates of skin irritation and related issues in recent years are actually caused by soap and beauty products themselves. The very products that are supposed to be helping us are actually harming our skin and our health. Well, sort of.

Apart from the toxic, carcinogenic, irritating, and allergy-causing ingredients in modern soaps, there is significant value in regular washing with soap.

Soaps help us to maintain proper hygiene and eliminate certain germs that may cause diseases. But some germs are fundamental to the proper functioning of our skin, and zero-tolerrance stances on germs cause more harm than good. By cleaning, showering, shampooing, conditioning, moisturizing, and deodorizing our bodies every single day, we strip away the germs that protect our skin and let it function as it is meant to.

Dr. Skotnicki cites examples from the US and Europe where cases of eczema (and the related issues of hay fever and asthma) have multiplied in the span of just a few decades. She also notes that skin irritation has become an epidemic with 40% of the US population (and 69% of women) now believing they have sensitive skin. Acne cases are also increasing, especially in women.

For years, beauty brands have taught us that daily showering along with multiple daily applications of soaps, moisturizers, and lotions should be part of everyone's skincare routines. Anyone who didn't agree was labelled as "dirty". But Dr. Skotnicki believes this cycle of constantly re-applying chemicals to treat symptoms is actually causing more problems.

After all, our skin’s natural oils, sweat glands, and microbes have helped us stay healthy for hundreds of thousands of years with only occasional cleaning (sometimes none at all). Only in the last 100 years have we decided to augment our skin's natural abilities with chemical solutions.

Rick Smith & Bruce Lourie also found concerning results from personal care product toxicity research for their book Slow Death by Rubber Duck.

They found women who wore perfume had 3x more phthalates in their urine as women who did not wear perfume. They also highlight a 2004 study from Dr. Philippa Darbre that discovered parabens in breast tissue. Dr. Darbre also found that 50-60% of breast cancer cases start in the quadrant of the breast closest to the armpit (where deodorants containing parabens are applied).

What Is Soap Made Of?

Now we finally have a better understanding of what soap is made of.

For most of human history soap was made from simple ingredients like tallow and lye. But once people began seeing germs as threats, they began seeking more ways to kill them. Soap makers capitalized on these fears and insecurities by designing proprietary soaps made from chemicals to cut costs and signal their product was unique.

But over time, it became clear that these chemicals introduced health risks, which are compounded by the fact we now wash our bodies more often than any other time in human history.

As evidence of skin, health, and environmental problems caused by soaps and beauty products piles up, what are we supposed to do in response? Dr Skotnicki believes the answer is not to add additional products, but rather to subtract from the products and ingredients people already use along with reducing the frequency of washing.

What Makes Soap Extraordinary?

Recently I replaced all my soaps, shampoos, and other skincare products with tallow soap and I'm pleased with the results. It is a simple, neutral soap that humans have used for thousands of years without any of the chemicals used by supermarket soaps.

This is the pure tallow soap I use with just two ingredients (100% grass-fed beef fat and lye), and this is an olive oil soap for those who want a simple soap without animal fats. It has just 5 ingredients.

Tallow soap does exactly what it is supposed to do. It cleans my body without artificial scents, carcinogens, allergens, or irritants. In doing so, it has opened my mind to the possibility that when it comes to soap, less can be more.

Against the backdrop of a soap industry creating countless chemical soaps designed for every body part, for every skin condition, and made of harmful ingredients, the simplicity of tallow soap makes it extraordinary.

Soap Ingredients Table

The following table shows the frequency which each of the following 83 ingredients were mentioned in the 22 bars of soap examined.