How To Properly Use Castile Soap

The more technologically advanced society becomes, the stronger the urge to return to simpler times seems to grow. Today's bath, body, and skincare products can come with incredibly complex ingredients and high price tags to match. Often, showers and medicine cabinets end up filled to the brim with dozens of products marketed as necessities for keeping your skin and hair fresh and clean. The backlash from the pressures of high-priced skincare and hygiene routine products has created a wave of re-popularized simple, old-world basic staples, like Castile soap.


If you've ever wished you could simplify your bath and body routine or reduce your skincare routine to the bare minimum, switching to Castile soap — a natural vegetable oil-based cleanser — might be right for you. We've discovered the most important facts about the cleanser, so you don't have to. Consider this your guide to Castile soap and all its beauty, skincare, and personal hygiene-related benefits, as well as its potential drawbacks for specific individuals.

What is Castile soap?

Traditionally, Castile soap refers to soap created in Castile, Spain, using pure Mediterranean olive oil. Today, a cleanser may be considered Castile soap as long as it is non-toxic and biodegradable vegetable oil-based. This is notable because most traditional soaps are made from a tallow base derived from animal fat. While many brands have moved away from tallow and toward synthetic ingredients, according to the Environmental Working Group, even major names like Dial and Ivory still use the ingredient in their bar soaps.


Castile soap is always plant oil-based and can be found in liquid or bar form. A modern version might feature traditional olive oil or any blend of oils like coconut, avocado, almond, and hemp. Essential oils are often added for their scent or anti-bacterial qualities. Castile soap is concentrated, meaning it must be diluted with water before use. Its natural, biodegradable nature makes Castile soap suitable for multiple hair and skincare uses and even housekeeping, laundry, and bathing your pets.

What are the benefits of using Castile soap?

Castile soap has much to offer, depending on what you want in a cleanser. The fact that it is natural, biodegradable, and plant-based is considered a significant pro to many concerned with their carbon footprint, those with allergies, asthma, or sensitive skin, and people who are morally opposed to using or consuming animal products. The concentrated nature of Castile soap also means it can be stretched to be very cost-effective.


Castile soap can be used to clean basically everything in your home — including your laundry, floors, dishes, and dog —along with your skin and hair, which is a major bonus for people who like to keep their routines simple. Imagine needing only one product for every person, place, and thing you're responsible for cleaning. It's hard not to see the upside of a product that can be used in a dozen ways while treating the planet and its inhabitants kindly.

Before you use Castile soap

Nothing in life comes without any risk potential. Despite Castile soap's positive qualities, it can present challenges for certain people. Due to the concentration level of the soap, it can be particularly drying to the skin and hair, especially if it isn't diluted enough. Some individuals may also react to various essential oils added to the soap (via the International Journal of Women's Dermatology). In addition, Castile soap is too alkaline for use on color-treated hair and will strip dye from your strands.


The alkaline nature of Castile soap also means that it should never be mixed with an acid, like lemon juice or white vinegar, both staples of natural cleaning. However, an acidic solution can be used to remove the salty film Castile soap can sometimes leave behind on surfaces due to its high concentration of minerals. These mineral deposits will be more prominent if your home has hard water and may become severe enough to change your mind about cleaning certain surfaces with Castile soap. 

Castile soap for skincare

The absence of synthetic ingredients in Castile soap can make it a preferable facial cleanser for people with sensitive skin or allergies to common skincare ingredients, according to Medical News Today. If you've struggled with adverse reactions to complicated cleansers or other skincare ingredients in the past, switching to a simple, natural cleanser like Castile soap might be precisely what you need. On the other hand, if you struggle with very dry skin, there's a chance that Castile soap will be too drying despite its oil base.


The only way to know whether or not Castile soap will work well for your unique skin is by swapping it with your usual cleanser. If your skin feels drier than average after cleansing with Castile soap, try diluting it with more water. If the dryness persists — even with proper moisturization — Castile soap may not be in the cards for your skincare routine.

Castile soap for haircare

When considering Castile soap as a shampoo substitute, be mindful of the state of your home's water. If your home has hard water, your hair could end up coated with the same kind of mineral deposit film that Castile soap can leave on counters and floors. Sticking to shampoo might be the best option unless you're willing to commit to washing your hair with bottled or filtered water.


If hard water isn't an issue, Castile soap can be a great limited-ingredient option for those who struggle with sensitive scalps or sensitivities to the harsh chemicals in traditional shampoos. However, it can be a bit drying on hair and is not color-safe. "Despite the fact that it is a gentle cleanser, it's very clarifying and can end up stripping your hair color," Puracy hair care expert April Kayganich explained to Byrdie.

Be prepared to condition your hair religiously. You will also need to experiment to find the perfect level of dilution for your hair; Castile soap should never be used on skin or hair without first diluting it with water. You may wish to follow with an acidic vinegar rinse to remove any mineral deposits left behind. 


Castile soap for body cleansing

Castile soap makes an excellent body wash for those with sensitive skin or concerns about their environmental impact. To wash your body with Castile soap, follow the same dilution procedure you would for facial or hair cleansing. You may discover that you prefer to add more or less water to the concentrated soap for each purpose. If your skin feels dry after cleansing with Castile soap, further dilute the mixture during your next bath or shower.


For most people, a simple, natural, multi-purpose product like Castile soap is worth a try for its potential health, environmental, and financial benefits. However, there is no one-size-fits-all solution for personal hygiene products. If Castile soap doesn't work for you, chalk it up to another lesson learned and find your own perfect combination of products that make you feel clean and confident in your skin.