Free U.S. Shipping $49+

Free U.S. Shipping $49+

Free Shea & Cocoa Butter Lotion $69+ | Exfoliating Body Wash $99+

Free Shea & Cocoa Butter Lotion $69+ | Exfoliating Body Wash $99+

7 Harmful Chemicals In Soap & The Best Soap Alternatives

by Michael Koh

Whether you suffer from a severe skin condition, experience above-average skin sensitivity or even just have “normal” skin (whatever that is), you’ve likely wondered more than once whether the chemicals in soap are bad for you and if there are more natural alternatives.


As is so often the case with these things, there’s good news and bad news.


The bad news is that for the most part, the caustic chemicals used in soap making and the many others added to create foam, preserve the product and make it smell pretty can have undesirable effects on the skin and deeper tissues, especially when used over a lifetime.


The good news, as you may have guessed, is that there are indeed natural soap alternatives that can provide the same cleaning benefits as regular soap without any of the nasty side effects, especially for those with more sensitive skin types.


Understanding soap ingredients and product labels


“Paraben free soap” is all the rage these days, along with a number of other catchy yet misleading marketing terms, potentially even including the phrase “natural soap” itself (more on this in just a second).


Unfortunately, the rot runs a lot deeper than just parabens, SLS and other common soap ingredients, and includes a lot more product categories than just soap. Everything from your cosmetics to your toothpaste may be slowly poisoning you unless you’re using truly natural alternatives or products made with chemical ingredients that have been exhaustively tested and/or developed by specialists such as dermatologists or scientists who specialize in this kind of work.


But fear not! In the rest of this article we’ll break down the BS, identify ALL the major culprits you need to look out for - including common name variations - and help you get to the bottom of all of this.


Bowl filled with lye (AKA Caustic soda), the main ingredient in soap

A bowl filled with lye (AKA Caustic soda), the main ingredient in soap.


What chemicals are in soap?


Lye in soap


To start with, we’d just like to make it clear that all soaps (even so-called natural ones) are made using a caustic chemical called lye. You may see it under different names, but ultimately soap is by definition made with lye (AKA Caustic soda). It is the key ingredient in most bar soap, bodywashes, shampoos and and detergents.


Lye is a metal hydroxide that is usually obtained by a process of leaching wood ashes or some other highly alkali substance that is water-soluble. This normally takes the form of sodium hydroxide and, less often, potassium hydroxide. On its own, lye is a dangerous substance that can cause severe corrosive burns to the skin and can permanently damage internal organs or even lead to death when swallowed.


When done correctly, the process of saponification sees lye combine with other chemicals to become soap that should, in theory at least, be totally harmless - especially when those other ingredients consist of natural oils, fats and butters rather than synthetic chemicals.


In practice, it doesn’t always work out that way.


While soap is an effective way to clean things and may not be dangerous per se, it can still strip your skin of moisture and for those with sensitive skin, even natural soaps can be a total nightmare.


And that’s before we even start talking about some of the stuff they throw into the most popular soap brands, cosmetics and other personal care products…


Harmful chemicals in soap


1) Sodium Lauryl Sulfate (SLS)


 Hands with foam that is created by adding surfactants such as SLS and other harmful ingredients to soap

The foam in most common cleaning products is created by adding surfactants such as SLS and other harmful chemicals.


SLS is an extremely common surfactant found in many soaps and other cleaning products for body and home. Surfactants serve a dual purpose, acting as both a foaming agent and a detergent that removes fat, oil and grease.


Also known as Sodium Laureth Sulfate, and not to be confused with the gentle Sodium Lauryl Sulfoacetate, SLS has been linked to skin irritations and allergic reactions such as eczematous dermatitis.


It bonds with other common soap ingredients, resulting in carcinogenic nitrosamines - chemicals that feature in California’s Proposition 65 list of known human carcinogens and endocrine disruptors.


Most soaps on the market today contain SLS and this is one of the main reasons why they leave even mildly sensitive skin damaged and irritated.


SLS is also found in almost all off-the-shelf toothpaste brands and a range of other hygiene and cosmetics products, meaning it should be one of the first ingredients you look out for if your goal is to avoid the harmful chemicals in soap.



2) 1,4 Dioxane



Another common contaminant found in many cosmetics and products meant for personal care, as well as good old Prop 65, is 1,4 Dioxane.


This compound is listed as a probable human carcinogen and an animal carcinogen. Research has shown that it easily penetrates the skin and excessive exposure has been linked to organ toxicity.


The worst part about this common soap chemical is that you won’t see it on any labels. That’s because the FDA does not require 1,4 Dioxane to be listed on labels as it is a byproduct of the manufacturing process rather than an ingredient in and of itself.


It can occur when chemicals such as SLS, PEG compounds, and others that include the clauses xynol, ceteareth and oleth are combined using a process called ethoxylation.


Looking out for ingredients with the above-mentioned clauses in their names is one way to avoid 1,4 Dioxane. The best way, in our humble opinion, is to stick to natural and/or dermatologically tested products for all your self-care needs!


Proposition 65 warning label: WARNING This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.


3) Parabens


Parabens in soap serve as preservatives that extend the shelf life of the product. They are common in soap, shampoo, cosmetics and shaving products, as well as a host of processed foods and pharmaceuticals.


The FDA lists propylparaben, butylparaben and methylparaben as the most common forms of this chemical, but any ingredient with the clause ‘paraben’ attached to it, as well as the name parahydroxybenzoate, should set alarm bells ringing.


Studies suggest that parabens can disrupt hormones and negatively affect fertility and reproductive organs, as well as harm birth outcomes and increase the risks of developing certain types of cancer. Even if you manage to avoid those ghastly worst-case scenarios, parabens are also a common cause of skin irritation.


According to the CDC, scientists found methylparaben and propylparaben in the urine of most of the people they tested, with women showing much higher levels than men - most likely down to their greater use of cosmetics and personal care products.


 Close up of a face with irritated skin, which can be caused by common soap ingredients such as parabens

Parabens and other soap chemicals can cause skin irritation or worse.


Luckily, it’s super easy to find paraben free soap and other personal care products with nothing but a quick Google search. Easier yet, simply head over to our Tree to Tub collections, where you’ll find products made with soothing botanicals rather than the nasty soap chemicals on this list!


4) Triclosan


Triclosan is a pesticide with antibacterial and antifungal properties. It has a hazard rating of 7 in EWG’s Skin Deep Cosmetics Database and even in low concentrations has been linked with changes in thyroid hormone concentrations and disruption of the endocrine system. It is also classified as a skin, eye and lung irritant.


Triclosan was banned as an ingredient for antifungal or antibacterial soap in 2016. Yet, for some reason that we mere mortals will probably never understand, it is still permitted for use in other everyday products ranging from shampoos to deodorants and toothpaste.


5) Ureas & Other Formaldehyde Releasers


Ureas like Diazolidinyl urea and chemicals like quaternium-15 (to name just a few of the bond villain worthy names given to these compounds) are relatively dangerous by themselves, but it’s when they release the highly toxic chemical formaldehyde that they really become a problem.


With the maximum EWG hazard rating of 10, formaldehyde is obviously something you want to stay away from. It is a known human carcinogen, human respiratory toxicant, skin irritant and environmental toxin.


Found in everything from soap (including baby soaps) and shampoo to nail polish, hair gel and color cosmetics, formaldehyde-releasing preservatives are a serious and under-addressed public health risk.


If you still needed any more reasons to carefully check the ingredients on your next soap purchase, you probably don’t anymore.


Tiny balls of chemical fertilizer, which can contain ureas and other common soap ingredients.

The most common use for ureas is actually chemical fertilizers, some of which also contain other common soap ingredients.


6) Synthetic Fragrances


The term fragrance refers to anything that is added to a product to alter its smell, and there can be dozens of such substances on a single product label. As you would imagine, unless you’re shopping in a store that only sells natural products (and even sometimes in that case), most fragrances you encounter will be made from synthetic chemicals.


Aside from soap, you’ll find synthetic fragrances in everything from household cleaning products and air fresheners to hand creams, candles, incense, and even whiteboard markers.


Most of the synthetic chemicals used in fragrances are petroleum-based and are known to be detrimental to human health. They include the near-ubiquitous and increasingly worrisome family of chemicals including phthalates and DEHP, as well as known endocrine disruptors and carcinogens benzophenone and styrene. People with sensitive skin, including children, are at higher risk of developing allergic reactions to synthetic fragrance chemicals.


7) DEA & Other Ethanolamines


Like many of the other chemicals in this list, ethanolamines can be found in a dizzying variety of consumer products ranging from personal care and cosmetics to household cleaning products and candle wax.


The most well-known compound in this group is diethanolamine (DEA), which is banned for use in self-care products and cosmetics in the European Union. This is because it and related chemicals such as MEA, TEA, and others are known to increase the risk of exposure to carcinogenic nitrosamines and cause organ toxicity, as well as causing environmental damage.


Woman checking ingredients on a bottle

It's always a good idea to read ingredient lists on soap and other products, but you need to know what you're looking at!


Soap alternatives


What if you’ve already tried every natural soap brand and still experience skin issues?


While not all off-the-shelf soaps contain one or all of the chemicals mentioned above, it seems fairly obvious that the easiest way to avoid the most harmful chemicals in soap is to simply skip the stuff altogether.


But is there anything out there that can do the job that soap does without actually being soap?


Of course there is! It’s the 2020s - there are hundreds of alternatives to everything, many of them natural!


Between natural soap alternatives and dermatologically tested skincare products, there is no reason that you should expose yourself and your family to another day of harsh and potentially dangerous chemicals.


Best soap alternatives


Soapberries growing on a tree 




Yes, you read that title right. Not only does nature have some great soap alternatives, but one of them is so close to actual soap that it was named after it! 


If you’ve never heard of them, soapberries (AKA soapnuts) are the fruit from a genus of small trees and shrubs with the scientific name

Sapindus. There are around 12 species in this group, all of which grow in warmish temperate to tropical regions. There are both old world and new world species that have been used by various cultures around the world.


Soapberries contain a natural, low-sudsing detergent known as saponin. This gentle cleanser is not only perfect for sensitive skin but also a great soap alternative for anyone that prefers natural products to those continuing potentially harmful chemicals!


 Closeup of dried soapberries, Mother Nature's soap alternative

Soapberries are Mother Nature's soap alternative and can be found all over the world!


How to use soapberries


The easiest way to use this all-natural soap alternative is simply to break them open and rub them in your hands with a little bit of water. The resulting lather is an amazingly gentle cleanser that has been used by various cultures from around the world for thousands of years.


You may be surprised to see the foamy lather that they create, but also don’t expect the equivalent of a foam party in your hands - like what happens when you use products that contain SLS and other chemical foaming agents. 


You can easily buy soapberries online and like true soap, they are a multi-purpose cleaner that can be used as a laundry detergent, body wash, shampoo, natural baby soap, or for just about any other cleaning purpose. If you’re a proper DIYer, you may even prefer to grow your own soapberry tree in your garden!


Person washing their hands with soapberries


Tree to Tub soapberry products


If you’re not quite ready to go full primitive survival mode and lather yourself with raw soapberry juice, don’t fancy waiting 9-10 years for your own tree to grow, or simply prefer your self-care products slightly more refined, we’ve got you covered.


You see, Tree to Tub was founded to solve just the problem that you’ve encountered.


When we opened up shop there was not a single brand on the market that used soapberries or other natural soap alternatives as their core ingredient.


The few people in the western world who did were simply DIYing it, with a few opening mom & pop stores that had no real market penetration or effect on the wider conversation about soap alternatives.


In fact, even today this is still the way that many people prefer to do it, and we’re all for it! Making your own soap (and all your other hygiene and household products for that matter) is a great way to ensure that they are truly all-natural, as well as a really fun hobby.


But let’s be honest, not everyone has the time and/or motivation to truly see this kind of endeavor through, quite literally, from tree to tub. It can also be pricey if you’re not doing it at scale or funding it through sales on the side.


That’s where we come in.


Wherever possible, our products include natural and certified organic ingredients.


The star of the show, as you might imagine, is the humble little soapberry. For the most sensitive skin types, we offer fragrance free, PH balanced soapberry products combined with other nourishing natural ingredients such as aloe vera and coconut that are great for soothing and moisturizing the skin. Even our products for all skin types get their smell from essential oils instead of synthetic fragrances.


In short, they’re pretty awesome.


Of course, we don’t expect you to take our word for it. Order your free samples today by scrolling down to the bottom of our homepage and inputting your email into the relevant field (you only pay for shipping) or check out our thousands of *almost all 5-star* customer reviews on Amazon, Grove, iHerb, Google, Judge Me, etc.

 Tree to Tub raw, unscented and PH-balanced body wash


Other soap alternatives


While we truly don’t believe you’ll ever need to search for another soap alternative after trying soapberries or using our products, we’re more than happy to fill you in on some other soap alternatives (our competitors) anyway.


Brands like Cetaphil, Cerave, and others offer soap-free cleaners and cleansers, although most of them do contain synthetic chemicals (normally approved by dermatologists) of some kind.


In terms of other natural soap alternatives, Soapwort, or Saponaria, is also an excellent gentle cleaner that can be used on the body and even to clean your house if you can get your hands on a sufficiently concentrated solution.


Glycerin soap (while still soap) is also a decent alternative. It’s a more gentle soap that can be made with completely natural ingredients. Because of this, glycerin soap can be beneficial for people who have mildly sensitive skin or as an alternative for anyone wishing to avoid the most harmful chemicals in soap.


If you’re someone who doesn’t mind your friends and family thinking you’re totally out of your mind, you can use things such as clay, full-fat yogurt, whole wheat flour, or even mashed vegetables to cleanse yourself naturally - although we can’t personally vouch for these methods as we already have our own trusty natural solutions.


 Two bars of glycerin soap

While still technically soap, Glycerin soap is a more gentle alternative to most common brands.




Is soap toxic? Not exactly, but most off-the-shelf options, from bar soaps to bodywashes and shampoos, contain at least some potentially harmful ingredients, and even the most natural soaps can cause issues for those with sensitive skin because of the caustic chemicals used in soap making.


In other words, whether you suffer from a severe skin condition such as eczema or psoriasis, have above-average skin sensitivity, or simply want to avoid exposing yourself and your loved ones to harmful toxins, some of the main soap ingredients to avoid include Sodium Lauryl Sulfate, parabens, 1,4 Dioxane, and the others mentioned in this article.


To be truly sure that you’re doing that, the best solution is to simply stick to natural soap-free products and ingredients such as aloe vera, coconut oil, etc. At the very least, try to use gentle soaps like glycerin soap, those made with all-natural ingredients.



Thanks for the information it’s been very good and useful

Abhishek Chenwala

To the owner, Your posts are always well-received by the community.

Crystle Puig

This information really helped me. Thanks 🙌🏼❤️

Yame'o Waki

Leave a comment

Please note, comments must be approved before they are published

Back to the Blog