Castile soap is a very popular choice for personal care and cleaning. Be aware of these tips to know what to buy and to avoid low-quality brands with unnecessary and potentially toxic additives.
The first time you browse the personal care aisles of a health food store, it’s hard not to immediately notice the numerous, colorful bottles and bars of Castile soap on display.
These brands are obviously good sellers, which is why retailers allocate them prime shelf space.
Just because an item is popular and sits on the shelf of a health food store, however, doesn’t necessarily make it a healthy nor even a green choice.
Any veteran foodie or greenie knows this to be true!
So what’s the real story behind Castile soap?
Is this product truly worth your budget dollars to purchase? Is it a safe personal care item for your family to be using?
Or, is it just another product that has been twisted by manufacturers into a modern-day version of its historical self that has little resemblance chemically or otherwise to its traditional roots?
History of Castile Soap
Castile soap, pronounced “kas-teel”, is rooted in the traditions of the Eastern Mediterranean where Aleppo soap makers made hard cleansing bars out of laurel oil and lye.
Laurel oil is derived from the aromatic Laurus nobilis, an evergreen tree or large shrub with green, glossy leaves and is native to Syria.
To this day, the origins of Aleppo soap remain unclear. Claims that the Egyptian Queen Cleopatra and Queen Zenobia of Syria used Aleppo soap abound but have yet to be verified.
As of this writing, we only know for sure that this important precursor to Castile soap cleansed the skin and hair of humankind for millennia.
The common belief is that the Crusaders brought Aleppo soap back to Europe with them during the 11th century.
Since laurel oil was not available in this part of the world, it was replaced with olive oil in the Castile region of Spain.
Castile soap was born!
Castile soap is known today as any vegetable oil-based soap. This distinguishes it from soaps made with animal fat such as tallow, lard, or goat milk.
Hence, the Castile soaps of today are commonly made with olive oil, coconut oil, palm oil, and others.
Castile Soap-Making
Traditional Castile soap is made by blending olive oil and lye. Lye, also called caustic soda, is the common name for sodium hydroxide or potassium hydroxide. Both are highly alkaline, liquid compounds.
They are also very caustic. Food grade lye is used to cure a wide variety of foods with lower grades of lye used in drain de-cloggers and oven cleaners.
Both the sodium hydroxide and potassium hydroxide forms of lye are used in making soap. Sodium hydroxide is favored for making solid Castile soap with potassium hydroxide used for liquid soaps.
They are not interchangeable, however. Potassium hydroxide-derived Castile soaps are more easily dissolved and diluted in water and are hence favored for liquid soap production for this reason.
The typical cold process method for making Castile soap is as follows:
- Lye is mixed with water.
- Vegetable oils and fragrances blended into the lye mixture.
- The gradual chemical reaction between the lye and the fats produces a solid soap as the mixture ages or “cures” over a period of several months.
While the cold process method is very straightforward, the hot process method for making Castile soap is actually far more popular.
It significantly reduces cure time from months to a few weeks and requires a smaller amount of essential oils to scent.
Hot process Castile soap is made using either the stovetop, a crockpot, or even in the oven. Only olive oil, distilled water, and lye are needed. (1)
Commercial Brands
Due to the long curing time required to make traditional castile soap, consumers have flocked to commercial preparations.
The good news is that some truly traditional, green Castile soaps are available. The bad news is that consumers would do well to avoid some brands that include unnecessary, even toxic, additives.
What should you look for as an educated consumer?
First of all, the old rule of thumb “the fewer ingredients the better” definitely applies to Castile-based soaps. Ideally, a liquid or bar should contain just three ingredients: oil, distilled water, and lye (either potassium or sodium hydroxide).
All of these ingredients are considered safe, certainly in the dilute amounts found in Castile soap.
Even at full strength, the Environmental Working Group (EWG) identifies lye as a low health risk with skin, eye, or lung irritation possible only when precautions are not taken. (2)
This is why rubber gloves and protective eyewear is necessary when making Castile soap yourself at home.
As a result, buying Castile soap either in bar or liquid form from the store is definitely a green choice when the manufacturers use just a few simple ingredients.
Which Oil is Best?
Olive oil is the most traditional oil for authentic Castile soap. However, any healthy fat will do the job. Coconut oil and palm oil are other excellent choices from when sustainable sources that are ideally organic.
Avoid soy or canola-based Castile soap as these are likely GMO unless certified organic.
A GMO-based soap would likely contain pesticide residues and be an unsustainable choice from an environmental point of view.
Watch out for Toxic Additives
Additional ingredients beyond the three basic ones described above are not necessarily a problem.
As a savvy consumer, be sure to read Castile soap labels and be aware that some non-green, unhealthy additives are possible that you need to watch out for.
Some common additives to commercial brands of Castile soap include:
- Fragrance
- Citric acid
- Glycerin
- Ethanol
- Calcium Carbonate
- Tocopherol (Vitamin E)
- Menthol
- Xanthan gum
- Potassium Cocoate
- Baking soda
- Silica
- Sodium Chloride (salt)
- Variety of essential oils and herbal extracts
The three ingredients marked in red above are the ones that are cause for concern.
Glycerin and citric acid, while generally nontoxic according to the EWG Skin Deep database, could be of GMO origin (either corn for citric acid or soy oil for glycerin). Be sure to check with the manufacturer of the Castile soap brand you prefer to be sure of nonGMO ingredients.
The ingredient with the biggest risk in Castile soap is fragrance. It has as a high hazard (8 on a scale of 10) by EWG. Castile soap or any personal care product that contains it has these health risks:
The word “fragrance” or “parfum” on the product label represents an undisclosed mixture of various scent chemicals and ingredients used as fragrance dispersants such as diethyl phthalate. Fragrance mixes have been associated with allergies, dermatitis, respiratory distress and potential effects on the reproductive system. (3)
Safest Ingredients
In sum, if you purchase Castile soap in either liquid or bar form, ensure that the label lists only basic ingredients such as nonGMO vegetable oil(s), distilled water, and lye (such as this brand).
A natural preservative such as tocopherol (Vitamin E) is fine too.
If you really prefer scented versions of Castile soap, be sure to purchase only those that use essential oils or herbal extracts.
Avoid brands that contain the word “fragrance” on the label. This ingredient is not a green and healthy option for you or your family.
Synthetic fragrances can negatively affect hormone health among other risks.
Be aware that some brands market Castile soaps that are healthy and others that are not.
Yes, even within the same brand, you must double-check ingredients to be sure the one you buy is truly green!
If you are unsure about the brand you use, be sure to check it in the Skin Deep database for peace of mind! (4)
Most Popular Uses
The savvy consumer can find dozens of uses for Castile soap around the home. The top 10 most popular uses include:
- Bathing (including washing hands – MUCH healthier and greener option than probiotic-stripping anti-bacterial soaps!)
- Shaving
- Brushing teeth and gums
- Washing produce
- Washing dishes
- Laundry
- Mopping floors
- Bathing pets
- DIY pest control in and around the home and garden
Do you use Castile soap? If so, do you make it yourself or purchase from the store? What are your favorite ways to use this green cleaner around your home?
(1) Hot Process Method for Making Castile Soap
(2) Sodium Hydroxide (Lye)
(3) Fragrance
(4) Environmental Working Group Product Database
i totally agree!
Where can I get that soap dispenser?
I am amazed at the number of articles that include Dr. Bronner’s soaps as “GREEN” which include ‘PALM OIL’ as an ingredient which, if you investigate the extreme negative impact on the rain forests that the cultivation of palm trees for the oil is having. Millions of acres of rain forests have been burned and cleared just for the agriculture of palm tree oil. I, for one, would never consider this practice on the scale that’s being done as ‘GREEN’ and would not include products that contain palm oil in a class of products which you speak about. Organic or not, a DECREASE in the consumption (internally and externally) of palm oil would be ‘GREEN’. Arid areas would be better to cultivate palm trees for it’s oil than the destruction of the rain forests, and until this cultivation practice is utilized, I do NOT consider Dr. Bronner’s products worthy of this list.
I think a lot of the confusion stems from producers using the wrong terms for their soap and creating confusion. Just like Aleppo soap must contain bay laurel and olive oils, a Castile soap is specifically one made with primarily olive oil. A soap made from 100% coconut oil, or sunflower oil, or lard, or hemp, etc is going to have very different cleaning and moisturizing properties than a Castile soap, and a different environmental impact too. Unfortunately it seems like the term Castile isn’t legally-protected, or its protection isn’t well-enforced, so many producers are taking advantage of that and selling their miscellaneous soaps as Castile because of its name recognition and good reputation.
As a soapmaker I would recommend that people not look for the name “Castile” and instead look at the ingredients. Soap ingredient labels sometimes list what ingredients went in (“olive oil”, “coconut oil”, “sodium hydroxide”) and sometimes list what’s currently in the soap (“sodium olivate”, “sodium cocoate”). I don’t buy any soap that doesn’t list the ingredients, or that omits obvious ingredients from the ingredient list. If the label doesn’t have at least one of “sodium/potassium X-ate”, “saponified X oil”, “lye”, “sodium hydroxide”, or “potassium hydroxide”, then they are lying about what’s in the soap and omitting any ingredient they think sounds “scary”, which might mean they’re omitting just the lye, but often means they’re omitting fragrances, dyes, and other mystery additives. There is no such thing as a lye-free soap so if someone is trying to sell you one, they are simply not telling the truth.
I also pay attention to which oils are used in the soap. Most soaps that are made with 100% of one oil are actually not super great. Lard soap I love, but coconut oil soap will dry out your skin on its own (yes, even if superfatted — in that case you’re stripping off all your natural oils and then replacing them with coconut oil). True Castile soaps made by most small soapmakers tend to be a bit slimy (as it’s one of the more difficult soaps to make well on a small scale). If I can’t find lard soap from an ethical producer, I would go for a soap that has a good balance of 2-4 different oils. Coconut and olive oil is a very common basic recipe and the two oils balance each other out well.
+ Michelle M, and anyone else who finds commercial Castile soaps drying: sometimes these Castile soaps are made with a high proportion of either palm or coconut oil. If not sufficiently superfatted (a percentage of the oil is left unsaponified, or not turned into soap) both of the oils will cause the soap to to be excessively drying.
My suggestion would be to find an artisanal soap maker in your community, or Etsy, that sells their best vegan soaps for those work sensitive skin.
6, for one, decided to make my own soap when I found that no matter how gentle a soap claimed to be, including Dr.Bronner’s, it made my skin so dry it itched and burned.
My soaps are no less than 45% olive oil, about 30% palm, no more than 12% coconut oil, plus I add at least 5% castor oil to the mix. The difference is sometimes sweet almond oil or lard or tallow from local sources. I’m NOT vegan or vegetarian, plus both lard and tallow make a very mild and hard bar of soap.
Despite how scary working with lye sounds, making soap is relatively easy and LOTS of fun! If you follow the best practices guidelines, and watch Soaping101.com YouTube videos, you’ll find yourself with some of the BEST soaps you couldn’t afford otherwise.
Hi first time using Castile soap. Have you heard of or have any opinion on Green Beaver Castile Soap.? It’s 3 ingredients but mostly sunflower.
What do your recommend Dr. Bronner’s Pure-Castile Liquid Soap – Baby Unscented, 32oz.
It contains Citric acid and this is one of the ingredients you do not recommend.
Here are the ingredients listed on their website:
Ingredients:
(INCI): Aqua, Potassium Cocoate (Saponified Coconut Oil*‡), Potassium Palm Kernelate (Saponified Palm Kernel Oil*‡), Potassium Olivate (Saponified Olive Oil*‡), Glycerin*, Potassium Hempseedate (Saponified Hemp Oil*), Simmondsia Chinensis (Jojoba seed oil*), Citric Acid, Tocopherol (Vitamin E), Helianthus Annuus Seed Oil (Sunflower Oil).
Very confusing, would appreciate some clarity.
Regards,
Sandrine
This organic castile soap is excellent. https://amzn.to/2So9HYQ
Citric acid is worse when you ingest it via processed foods … on the skin is not ideal but definitely not as serious a situation.
Hi Sarah
Is Naissance a reputable company for natural products?
I have not looked into that brand.
Extremely drying, when I use this soap my skin turns very ashy and it flakes off. What can I do about this? I am prone to dry skin on my body and oily skin on my face.
I love my Castile! I always have a bar in my medical kit at my horse farm. Its great as a surgical scrub for cuts and irritations etc. We also use it to clean the delicate sheathes of male horses. It doesnt burn or irritate them