Image text: “Breast, Uterine, and Prostate Cancers Are Rising Rapidly / The Shampoo & Treatment You Use Every Day / May Be One Cause”
Shampoos, conditioners, and treatments have become indispensable in our daily lives. However, did you know that the chemical substances contained in them, called "surfactants," can have serious effects on our health?
In particular , " cationic surfactants " found in hair treatments, conditioners, fabric softeners, and deodorizers pose a risk that cannot be overlooked.
"But shampoo and conditioner are rinsed off, so it should be fine, right?"
If you think so, please read this article to the end. The transdermal absorption rate of the scalp is 3.5 times higher than that of the inside of the arm . Even if you think you're washing it all away, chemicals are definitely getting into your body.
- What are surfactants—chemicals that are everywhere in our lives?
- It's dangerous if you use it every day! -- The effects of cationic surfactants on the body
- The skin is not a barrier, but an "absorption organ"—the transdermal absorption rate of the scalp is 3.5 times higher than that of the arm.
- Surfactants break down the barrier, creating a vicious cycle that further accelerates absorption.
- Is the accumulation of long-term use truly unrelated to the increase in breast, uterine, and prostate cancers?
- The health benefits of going shampoo-free and skin fasting
- How to Get Started: Going Shampoo-Free & Skin Fasting
- But for those who want to thoroughly cleanse their scalp—a botanical shampoo bar born in Hokkaido.
- Key Features & Our Commitment
- Zero synthetic surfactants - solid shampoo derived purely from plants
- By the way, let me answer the question, "Isn't soap also a surfactant?"
- The "kettle-boiled method" that has continued since the Edo period—the reason why quality was chosen over efficiency.
- Through repeated prototyping—my own transformation
- Summary: To maintain a healthy body and beautiful hair
What are surfactants—chemicals that are everywhere in our lives?
Surfactants are chemical substances that act to mix substances that do not normally mix, such as water and oil, and are used in a wide range of products, from shampoos and treatments to dishwashing detergents and cosmetics.
However, most people currently use these chemicals without knowing the adverse effects they can have on the body.
Types of Surfactants
There are four main types of surfactants:
It would take too long to explain in detail here, so for more information please see the explanation page of the Japan Surfactant Industry Association .
Among those deeply involved in our daily lives are anionic surfactants and cationic surfactants .
Problems with strong anionic surfactants
The " anionic surfactants " contained in shampoo thoroughly remove dirt from hair and scalp, but their strong cleansing power destroys the scalp's barrier function, causing dryness and irritation . As a result, hair becomes prone to static electricity and feels rough or squeaky after shampooing alone.
Therefore, "cationic surfactants" are used as a countermeasure.
Why do we have to use chemical conditioners and treatments after thoroughly washing our hair with shampoo? This is because conditioners and treatments contain cationic surfactants with the opposite charge, which neutralize the hair and scalp and improve how they feel.
However, it is these "cationic surfactants" that pose a significant risk to the body .
It's dangerous if you use it every day! -- The effects of cationic surfactants on the body
" Cationic surfactants " are used to reduce static electricity on hair and scalp, but they can actually have serious adverse effects on our bodies. Research by Professor Terry Hrubec of Virginia Tech University in the United States has revealed that these chemicals pose significant risks to human health.
A chance discovery—an anomaly in the laboratory
Professor Hrubec's discovery began by chance.
In 2008, at Virginia Tech's animal research facility, the chlorine-based disinfectant they had been using was replaced with a disinfectant containing cationic surfactants (Quat). As a result, the mice being used in the experiments began to experience unexpected problems .
The number of ovulations in female mice decreased significantly . The sperm count and motility of male mice decreased dramatically . Both groups suffered serious damage to their reproductive functions. Furthermore, researchers were shocked to discover that the offspring had a high incidence of neural tube defects (abnormalities in brain and spinal cord development) and an increased fetal mortality rate .
Professor Hrubec continued his investigation even after discontinuing the use of disinfectants containing Quat, and found that Quat remained on the cage material for several months . In other words, this chemical does not easily disappear simply by "washing it off" or "stopping use."
References (evidence):
/Melin VE, et al. “ Exposure to common quaternary ammonium disinfectants decreases fertility in mice. ” Reproductive Toxicology , 2014; 50:163-170.
Melin VE, et al. “ Quaternary ammonium disinfectants cause subfertility in mice by targeting both male and female reproductive processes. ” Reproductive Toxicology , 2016; 59:159-166.
Hrubec TC, et al. “ Ambient and Dosed Exposure to Quaternary Ammonium Disinfectants Causes Neural Tube Defects in Rodents. ” Birth Defects Research , 2017; 109(14):1166-1178.
Kirkpatrick ZA, et al. “ Quaternary ammonium compound exposure causes infertility by altering endocrine signaling and gametogenesis. ” Reproductive Toxicology , 2025; 132:108817.
The toxicity mechanism of Quat—why is it so dangerous?
Our body's cells are protected by a thin layer of oil (cell membrane). Quat has a powerful effect that can destroy this oil membrane . In fact, this is the same mechanism that kills bacteria.
In other words, Quat is a chemical created to "break down and kill germs." This means that it may have the same effect on the cells in our bodies.
When a cell membrane is damaged, abnormalities may more easily affect the genetic material in the cell nucleus. That is why Professor Hrubec’s experiments found reduced reproductive capacity and serious effects on offspring.
Furthermore, recent research has shown that Quat can fundamentally disrupt hormone balance .
These are the properties of so-called " environmental hormones " —chemical substances that pretend to be hormones in the body and interfere with their normal functions .
This isn't about temporary skin irritation or itching. It's about the substance slowly and gradually entering the body each day, quietly damaging fundamental bodily functions like hormones and reproductive health .
That's the real horror of Quat.
Comparison of anionic and cationic surfactants
Professor Hrubec's experiments have revealed that cationic surfactants pose significantly greater health risks than conventional anionic surfactants. For example, while the incidence of birth defects is only 0.1% when using anionic surfactants, that figure rises to 15%, 150 times higher, when using cationic surfactants .
As the results of this experiment show, the rinses, treatments, fabric softeners, and deodorants that we use every day without even thinking about them pose huge health risks.
In particular, the microbeads contained in recent fabric softeners utilize this cationic surfactant to create a long-lasting pleasant scent. Furthermore, deodorizers (cationic disinfectants) such as Feb●eze, which are commonly used by modern people, are neither cosmetics nor detergents, so the government does not regulate their usage levels. Therefore, there is no requirement to disclose how much of these products are present, making it unclear and ambiguous.
Because children and pets are smaller, the same environmental exposure can represent a greater dose relative to body weight than it does for adults. That is why it is especially important to be careful about the ingredients in products used every day.
▼ \ Are the clothes you're wearing okay? ／
My terrifying experience with a 699 yen hoodie. I'm sharing the real dangers of chemicals that penetrate the skin and how to protect yourself!
The skin is not a barrier, but an "absorption organ"—the transdermal absorption rate of the scalp is 3.5 times higher than that of the arm.
After reading this far, some of you may be thinking, "But shampoo is something you rinse off..."
However, our skin is not a complete barrier that blocks out external substances. Depending on the conditions, it can also be an "absorption organ" that allows components to be absorbed into the body .
The Truth About Transdermal Absorption Rates by Body Part
The transdermal absorption rates by area, using the inner arm as the baseline (1.0x), are as follows:
- Heel: 0.14 times
- Palm: 0.83x
- Back: 1.7 times
- Scalp: 3.5x
- Underarms: 3.6 times
- Forehead: 6.0 times
- Cheeks and chin: 13 times
- Genital area: 42x
The scalp has an absorption rate 3.5 times higher than that of the arm . Moreover, the scalp has a dense network of pores, making it easy for ingredients to reach the capillaries in the dermis through these pores.
The surface of the skin has a barrier called the stratum corneum, but its thickness varies depending on the body part. The forearm has about 14 layers, the face has about 9 layers, and the genitals have only 6 layers. The thinner the stratum corneum, the easier it is for external substances to penetrate.
▼ ＼ With a transdermal absorption rate 42 times higher, what do you use on your delicate zone every month? ／
Learn more about the chemicals in sanitary napkins and the option of organic napkins here.
Surfactants break down the barrier, creating a vicious cycle that further accelerates absorption.
However, for those of you who think, "Shampoo is something you use every day, and it says it's gentle, so it should be fine,"
The surfactants in shampoo have the property of penetrating the lipids ( intercellular lipids ) between keratinocytes. The surfactants break through the lipid barrier that is supposed to repel water.
In other words, the more you wash your hair with shampoo containing surfactants, the more the scalp's barrier is damaged, creating a vicious cycle where chemical substances can penetrate more easily .
Moreover, as Professor Hrubec’s research shows, Quat can persist on cage materials for months. In other words, even after conditioners or treatments are rinsed out, trace amounts of Quat left on the scalp or in pores may continue to be absorbed slowly.
Furthermore, pores open and skin temperature rises during bathing. It is said that soaking in warm water loosens the skin's barrier function, significantly increasing the absorption rate of chemicals compared to room temperature. In other words, using shampoo and conditioner in the bath creates the most efficient conditions for the absorption of chemicals.
Furthermore, cosmetics also contain large amounts of surfactants. Hand soaps and body washes use them to create lather, while lotions, serums, and creams use them to emulsify. We apply so many chemicals to our faces, heads, and bodies every day—it's truly frightening how much surfactant is used in our daily lives.
Is the accumulation of long-term use truly unrelated to the increase in breast, uterine, and prostate cancers?
Chemicals absorbed through the skin are carried throughout the body via the blood and lymph, and are said to accumulate easily in areas with adipose tissue , such as the brain and liver, the breasts and uterus in women, and the prostate in men . Daily hair care products may be the culprit behind unexplained health problems such as chemical sensitivity, allergic dermatitis, and hormonal imbalances.
There's something I'd like you to consider.
Breast cancer – the number of cases per year, which was about 20,000 in 1985, has now risen to about 91,000. That's a staggering 4.5-fold increase. Now, it's a time when one in nine women will develop breast cancer.
Uterine cancer – approximately 30,000 new cases are diagnosed each year. In particular, endometrial cancer has increased sharply by about nine times compared to the 1980s.
Prostate cancer – the number of cases, which was only about 4,000 in 1980, rose to about 95,000 in 2021. That's a 24-fold increase . It is currently the most common cancer among men .
All of these are types of cancer that have been increasing at an astonishing rate over the past few decades.
(Source: National Cancer Center Japan Cancer Information Service "Cancer Statistics")
Can the increase in these cancers really be explained solely by factors such as the Westernization of diets, an aging population, later marriages, and a decrease in the number of births?
Every day, synthetic surfactants penetrate the scalp, which has a transdermal absorption rate 3.5 times the absorption rate of the inner arm, and cationic surfactants (Quat) contained in rinses and treatments are continuously applied from the head to the entire body. Fabric softeners rich in Quat are used on clothes and bath towels used daily, and deodorizers are scattered throughout the room... Due to these lifestyle habits, which are full of endocrine disruptors, chemical substances accumulate in the breasts and uterus of women, and in the prostate of men, over many years.
Can we definitively say that this fact is completely unrelated to the increase in breast cancer, uterine cancer, and prostate cancer?
I personally believe that one of the reasons behind the unusually rapid increase in prostate cancer cases among men is that men have started using shampoo and conditioner just like women. In the past, men were imagined as using soap to wash their face, body, and hair all together. Nowadays, men even use cosmetics.
Professor Hrubec's research has shown that exposure to Quat not only disrupts the hormone balance of female mice and significantly impairs their reproductive function, but also causes a significant decrease in sperm count and motility in male mice . Recent studies have revealed that Quat has the properties of an "environmental hormone," disrupting hormones in both males and females. Therefore, I am truly concerned that men should take precautions to avoid losing their reproductive capacity.
While we certainly cannot directly apply the results of animal experiments to humans, shouldn't we at least take more serious consideration of the risk factor of "chemicals entering the body through the scalp during daily hair washing" ?
The health benefits of going shampoo-free and skin fasting
As Professor Hrubec's research shows, the chemicals we use casually in our daily lives pose significant risks. Quat, found in rinses and treatments, may provide temporary beauty benefits, but in the long term, it can cause serious damage to our health . To avoid these risks, the practice of shampoo-free and skin fasting is gaining attention.
What is no-shampoo?
Shampoo-free hair care is a method of washing the scalp and hair with only hot water or soap, without using chemicals in shampoos, conditioners, or treatments, in order to restore the natural balance of sebum.
🌍In Europe and the US, a shampoo-free movement called "No-Poo" is rapidly spreading. With growing awareness of the damage synthetic surfactants inflict on hair and scalp, the number of people abandoning conventional shampoos is rapidly increasing. The sulfate-free hair care market is projected to reach approximately $5.1 billion (approximately 760 billion yen) in 2024 and grow further to approximately $8.2 billion by 2030. Rethinking shampoo is now a global trend.
While there are indeed benefits to not using liquid shampoo, the biggest advantage is that you avoid exposure to cationic surfactants (Quats) contained in the conditioners and treatments you use afterward, thus freeing your hair and scalp from strong chemicals.
Benefits of Skin Fasting
Skin fasting is also a way to minimise the use of chemical products on the skin and boost the skin's natural ability to regenerate.
It promotes the skin's ability to heal itself without using excessive chemicals, so it is expected to have the effect of fundamentally resolving skin problems.
In the next article, I'd like to write about "allergies caused by certain substances," which have been increasing rapidly recently. Please wait a moment. (It's finished! Please read it when you have time. "Wheat allergy from soap? Anaphylaxis from lipstick? The truth about chemicals that enter through the skin—5 real-life examples of epicutaneous sensitization" )
▼ \ I'll share my chemical-free skincare routine! ／
A must-see for those with sensitive skin. Here's a summer skincare routine based on dermatology that doesn't rely on chemicals.
▶︎Protect your sensitive summer skin! A complete guide to a dermatologically-based summer skincare routine.
How to Get Started: Going Shampoo-Free & Skin Fasting
If reading this article has inspired you to try shampoo-free or skin-fasting, you can start right away. We recommend brushing your hair before washing to remove some of the dirt.
Try using the Watabana series body mitts, which don't require detergent, on both hands and gently wash your scalp and body with warm water. The specially processed organic cotton yarn removes excess sebum and dirt.
For those with oily skin, scallop powder water is also effective. It's a strongly alkaline water with a pH of 12, but there's no risk of "chemical burns," so please use it with confidence. However, it's quite strong, so absolutely do not use it every day. Also, it doesn't lather, so some people might feel like they haven't washed properly.
If your hair feels stiff or dry, spray it with citric acid solution as a rinse at the end to neutralize it before rinsing.
By the way, I use this scallop powder for everything from washing dishes and doing laundry to bath additives and deodorizers!
▼ \ From washing dishes to laundry, bath salts, and deodorizers! /
One scallop powder can completely transform your life. Here's a complete guide to using it in ways that are kind to both the environment and your body.
Additionally, if residual conditioner or treatment ingredients are causing breakouts on your back, it is important to gently scrub with a Watabana Series body towel.
If possible, wash using only warm water and no cleanser. Organic cotton yarn spun using the Garabo method developed in the Meiji era contains more air than ordinary yarn and gently removes excess sebum and dirt.
For washing your face, how about this mini mitten from the Watabana series ? It's a small mitten that comfortably fits three fingers (index, middle, and ring fingers).
After use, wash it lightly with hot water and hang it in the bathroom, and it will dry very quickly. Please occasionally disinfect it by boiling it or wash it with scallop powder water.
Its compact size makes it easy to clean around the sides of the nose and behind the ears. Light makeup can be removed with just this mitt and warm water.
By the way, I use this to clean my tongue and massage my gums after brushing my teeth in the morning and evening as part of my daily routine.
But for those who want to thoroughly cleanse their scalp—a botanical shampoo bar born in Hokkaido.
"I understand the logic behind going shampoo-free. But sometimes I just want to thoroughly wash my scalp."
For people like you, I have poured my heart and soul into developing the "Botanical Shampoo Bar," which uses rare ingredients sourced from Hokkaido .
Botanical Shampoo Bar 60g Solid Shampoo Additive-Free Hokkaido Japanese Mint
For those troubled by an oily scalp or dandruff: a 60 g Botanical Shampoo Bar made with ingredients nurtured by Hokkaido’s natural environment. Its pure soap ingredients, free of synthetic surfactants, gently remove dirt and support a healthy scalp. Refresh with the rare scent of Japanese mint. Suitable for the hair and entire body.
🎉It 's been out of stock for a long time, but it's finally back in stock!
The origin of development: The fight against scalp problems in Taiwan
When I was living in Taiwan, I suffered from serious scalp problems.
Itching, dandruff, hair loss, skin irritation, acne on my back... I was diagnosed with seborrheic dermatitis at a dermatologist, and I tried everything from prescribed medications to shampoos that are supposed to be good for the scalp.
However, although there was a brief improvement, the condition quickly worsened, and ultimately no fundamental solution was found.
Maybe the climate doesn't suit my constitution... Or maybe I'm under too much stress...
Even after changing my lifestyle, nothing improved, and after much trial and error, I finally arrived at " hot water washing ," a hair washing method that completely eliminates chemical substances.
In Taiwan, with its high temperatures and humidity, the challenge of going without shampoo was incredibly difficult; it would have been impossible without extraordinary determination. However, after a year and a half, my symptoms finally completely improved.
Every time I share my experience, I get a huge response and learn that there are so many people out there who are suffering in the same way.
When I think back to the pain I felt at the time, I felt strongly that I could have resolved the issue in a more natural way.
▼ \ You can read more about the development story in this blog /
How did I, who have continuously battled seborrheic dermatitis, end up finding ingredients from Hokkaido? Read the full story here.
My encounter with SORRY KOUBOU—a shampoo bar born from the nature of Hokkaido
Therefore, with the help of the Hokkaido skincare brand " SORRY KOUBOU ," we began developing a shampoo bar that uses absolutely no chemical additives, harnessing the power of plants produced by Hokkaido's rich natural environment.
The two women who run SORRY KOUBOU have personal experience of overcoming severe atopic dermatitis by eliminating chemicals and relying on the power of nature. They are committed to handmade products, from cultivating the herbs used as raw materials to manufacturing the finished products.
Key Features & Our Commitment
BOTANICAL SHAMPOO BAR
Artisan-Crafted in Hokkaido, Japan
✔ Contains absolutely no synthetic surfactants or quats.
✔ Silicone and preservative -free
✔ Hokkaido-grown Japanese mint × fir × bergamot essential oil
✔ The "kettle-boiled method" that has been used since the Edo period.
✔ High-density finish achieved through one month of natural drying.
✔ Everything from molding to packaging is done by hand.
It can be used by people of all ages and genders, and in all seasons , not only on the scalp, but also on the face and entire body.
Zero synthetic surfactants - solid shampoo derived purely from plants
This shampoo contains absolutely no synthetic surfactants. Of course, it also contains no cationic surfactants (Quat). It's a solid shampoo made only from pure plant-derived ingredients, free from silicone and water.
In addition to natural essential oils of Japanese mint and fir from Hokkaido, we have now added bergamot essential oil (phototoxicity-free) to stabilize the fragrance. The refreshing scent is complemented by a subtle warmth of citrus, resulting in a fragrance that can be enjoyed by people of all ages and genders, all year round .
By the way, let me answer the question, "Isn't soap also a surfactant?"
After reading this far, some of you may be thinking, "But isn't soap also a surfactant?"
Actually, that is correct. The main components of soap, sodium salts of fatty acids and potassium salts of fatty acids, dissociate into negatively charged ions in water and are therefore classified as anionic surfactants.
However, even though they are both called "surfactants," soap and synthetic surfactants have completely different effects on the body.
Synthetic surfactants like sodium lauryl sulfate, commonly used in commercially available shampoos, are problematic due to their high persistence and strong skin irritation. On the other hand, soap is made from natural oils and alkalis, is highly biodegradable, and leaves little residue on the skin . It rinses off easily with water, leaving minimal residue on the skin.
Our botanical shampoo bars are made using only natural soap ingredients . They contain absolutely no synthetic surfactants, nor any cationic surfactants (Quats). We want you to understand that they are completely different from the chemical substances whose dangers we have discussed in this article.
The "kettle-boiled method" that has continued since the Edo period—the reason why quality was chosen over efficiency.
We also paid close attention to the manufacturing process. We adopted the "kettle-boiling method," which has been practiced since the Edo period.
In modern soap making, the "cold process method," which reduces costs and time, is the mainstream. However, we have deliberately chosen the opposite method: the kettle-boiling method.
In the kettle-boiling method, craftsmen heat and stir oils and alkalis in a large kettle for many hours to achieve complete saponification . This leaves no unreacted oils, maximizing the soap's cleaning power while leaving natural glycerin as a moisturizing ingredient , resulting in a finish that balances cleansing and moisturizing.
Furthermore, a month of natural drying after manufacturing allows the moisture to slowly evaporate, resulting in a denser soap. This is why, even though it's small, it lasts a very long time, producing a fine, firm lather that doesn't collapse easily.
From molding to drying and packaging, everything is finished by hand. Each and every item embodies the passion of the craftsman, resulting in a quality that can only be achieved through manual work .
▼ \ Soap can cause you to lose the ability to eat noodles and bread?! ／
Here are five real-life examples of skin-related allergies that have occurred in Japan. Don't think this doesn't apply to you! It's the adults around you who can protect your little family.
Through repeated prototyping—my own transformation
After many rounds of prototypes, I tested each one myself and shared what needed improvement, while the makers continued refining it.
What I noticed after using the prototype was that while itching and dandruff had improved from the start, I still had the problem of increased sebum secretion in the afternoons . It's really a minor issue compared to before, but it still bothered me.
However, as I continued using it, even that problem gradually disappeared as if it had never existed.
Before I knew it, my hair wasn't greasy even in the afternoon. I was able to regain smooth, silky hair all day long . My pores were cleansed, my hair became thicker and more voluminous , and I no longer had to worry about the oxidized smell of excess sebum that used to hit me in the evenings.
I wanted to share this joy with people who have similar concerns. I wanted them to improve their scalp condition naturally, without struggling through the transition away from shampoo or relying on medication. And that is how this Botanical Shampoo Bar was finally completed.
Incidentally, it's not just scalp problems; atopic dermatitis, rosacea, acne, itching, etc... For example, if you have problems around your chest, back, or face, the cause might actually be the long-term use of surfactants in shampoos and conditioners, which destroys the sebum film, or is worsening the condition! This is because these surfactants come into contact with your body when you rinse them off.
Even if you're currently doing a skin fast or shampoo-free regimen, try this gentle botanical shampoo bar for your scalp, gradually increasing the intervals between uses until it becomes a weekly treatment . Once your scalp environment is in order, you won't need to use it every day. That's proof that your scalp has regained its natural strength.
Summary: To maintain a healthy body and beautiful hair
The risks of surfactants contained in shampoos and conditioners are deeply related to our daily lives.
To summarize the facts presented in this article:
Cationic surfactants (Quat) are 50 times more toxic than anionic surfactants . In Professor Hrubec's research, they disrupted the reproductive function of mice and caused birth defects in the next generation. Recent research has also confirmed their properties as "environmental hormones," which fundamentally disrupt hormone balance.
The transdermal absorption rate of the scalp is 3.5 times higher than that of the arm . Moreover, the absorption is further accelerated when surfactants break down the skin barrier. The efficiency increases by another 10 times due to the rise in temperature during bathing.
The absorbed chemicals tend to accumulate in fatty tissues such as the breasts and uterus , and it cannot be definitively said that this is unrelated to the increase in breast cancer (91,000 cases per year) and uterine cancer (30,000 cases per year).
To protect your long-term health rather than focusing on short-term beauty benefits, it's important to incorporate shampoo-free and skin-fasting practices . And for days when you absolutely want to wash your hair thoroughly, there's the option of a botanical shampoo bar that contains absolutely no synthetic surfactants.
Little by little, you can free yourself from chemicals and have a healthier, cleaner body!
🛒 Products featured in this article
- Botanical Shampoo Bar 60g ── Now back in stock!
- 618 scallop powder
- Body mitt (100% organic cotton)
- Body towel (100% organic cotton)
- Mini facial cleansing mitt (100% organic cotton)
Related articles
▼ ＼ I’m showing you my bare skin! ／
If you want truly beautiful skin, I recommend trying “subtractive beauty.” I openly shared my current skin condition and explained the essentials of simple skincare.
▶︎ [ True beautiful skin comes from [subtractive beauty] - The secret of simple skin care ]
At Shoukakukou Store (小恰好商店), I, the owner, personally use and offer only carefully selected Japanese seasonings and foods that I truly believe to be the "real thing."
Comments