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Using Liquid Castile Soap for Shampoo

Welcome back to our new series: “The Many Ways To Use Castile Soap”!

In our last blog post, we discussed how to use liquid castile soap as a body wash.

Another one of our favorite uses for liquid castile soap is as a shampoo. Castile soap’s unique properties mean it is very effective at providing a deep clean without stripping your hair’s beneficial natural oils. However, the one exception is for people with color-treated hair. Typically using castile soap is not recommended for those with color-treated hair as the soap can strip the hair of artificial color (here [] is an all-natural shampoo option that is safe for color-treated hair). But if you do not have color-treated hair, or if you are not concerned with pigment loss, then liquid castile soap may be the shampoo for you.

As with most liquid castile soap applications, using it as a shampoo does require a bit of instruction. Keep reading to learn our favorite tips and tricks for using liquid castile soap as a shampoo.

How to Use Liquid Castile Soap as Shampoo:

castile soap as shampooOptional preparatory step:

Similar to when using liquid castile soap as a body wash, liquid castile soap as shampoo works best in different concentrations for different people, depending upon your hair’s density, texture, and natural oiliness or dryness of your scalp.

Many people enjoy using full-strength liquid castile soap to cleanse their hair and scalp, and it is absolutely safe to do so. If you choose to use full-strength liquid castile soap, you do not need to undertake any preparatory steps. However, because castile soap is much more alkaline than traditional shampoos, you may find that using it full-strength disrupts the pH balance of your hair, leaving it feeling greasy, waxy, tangly, or unmanageable. Undiluted liquid castile soap is also very concentrated and may be too difficult to evenly distribute and rinse fully. If this is the case, then you may find you have better results by diluting your liquid castile soap prior to using it as a shampoo.

If you choose to dilute your liquid castile soap, we highly recommend using distilled or filtered water. Liquid castile soap can react with hard water causing an excess build-up of minerals that become especially noticeable when using it to wash the hair. (For this reason, some people also choose to invest in a water-softening shower head.)

To use diluted liquid castile soap as shampoo, we recommend beginning by combining one-half tablespoon of liquid castile soap with one-half cup of filtered or distilled water in any container (with a lid) that you are comfortable using in the bath or shower. Take care when using glass containers as they can be slippery when wet – however, wrapping a couple of rubber bands around glass containers can help provide some additional grip. Some of our friends also report having great success using bottles fit with nozzles, such as those used for condiments or hair dye application (this can also be a great way to recycle old plastic bottles!). Of course, any bottle, jar, or cup with a lid will work, as well. Simply shake up your soap and water mixture before use.

REMINDER: If transferring your full-strength or diluted Castile to a separate container, make sure to choose a container that does not use pressurized dispensing (ex: a container with a pump). Since liquid castile soap will solidify at room temperature, choose a container that will allow you to avoid dangerous clogs and exercise more control when you pour or squirt the soap. We also do not recommend making your shampoo mixture in advance or keeping pre-mixed shampoo in a container for an extended period of time. Our soaps need no preservatives when they are stored at full strength, however adding water to the soap changes its pH, which can encourage bacterial growth and mold formation inside the container. To avoid this type of contamination, make sure that you are mixing the liquid castile soap and water immediately prior to use, and do not allow the pre-mixed solution to sit and become stagnant.

Step 1:

Detangle your hair and brush or comb it through to help remove any loose hairs. This will help with preventing tangling and matting after washing. Dispense a small amount of full-strength or diluted liquid castile soap into your palm, and apply it to your scalp the same as with traditional shampoo. If you are using a bottle with a nozzle, you can apply the soap directly to your scalp.

Step 2:

Gently but thoroughly massage your scalp with your fingertips, building the soap into a generous lather. Do not scratch your scalp with your fingernails, as this causes hair breakage. Also avoid piling your hair on top of your head when washing, as this will contribute to tangles and eventual breakage. Make sure to concentrate the soap on the roots of your hair, which tend to be oiler compared to the ends, and work the shampoo down the length of your hair as you rinse.

Step 3:

Rinse thoroughly!! This step is usually when you will be able to determine if you need to make adjustments to your Castile shampoo recipe. If your hair is especially thick or textured, you may find that it is difficult to evenly distribute undiluted liquid Castile, which due to the concentrated nature of the soap, can then make it very difficult to rinse out completely. Make sure that you are rinsing your hair until the water runs clear and your hair no longer builds a lather. Tipping your head side-to-side and upside-down under the running water can be especially helpful in ensuring your hair is rinsed fully.

Sometimes-optional Step 4:

Just as our bodies are unique, so is our hair. Some people will find that they love the way their hair feels after washing with castile soap and will require no further steps to achieve their desired end result. However, due to a number of variables ranging from the mineral composition of your water to the structure of your hair cuticle, some people may find that washing their hair with castile soap leaves it feeling “dirty” or “waxy”, or matted or unruly.

Typically, these results are due to the alkalinity of the Castile shampoo, which is good news because the solution couldn’t be simpler. If your hair feels icky after washing with castile soap, bring it back into balance by following with an acidic rinse, such as lemon juice or apple cider vinegar. Think of this step as similar to applying conditioner after washing with traditional shampoo.

If you are still struggling with dry hair after trying an acidic rinse, another solution is to try diluting your castile soap with coconut milk prior to use. For people with exceptionally dry or curly hair, it can also be helpful to use a deep conditioning treatment before and/or after shampooing. Some excellent all-natural DIY deep conditioners can be made from many household staples, such as avocado, banana, honey, aloe, and olive and coconut oils.

Transitioning to using castile soap as shampoo is just that: a transition. It is very normal for your hair to go through several different stages over the first few weeks of your new routine. Most people consider this to be their hair’s way of “detoxing” after (usually) years of dependence on chemical cleansers. If you are noticing an abundance of product build-up, try clarifying your scalp with a baking soda scrub, or doing an apple cider vinegar rinse before you shampoo. And give your hair time to adjust. Remember to be patient and kind to yourself as you adjust to your new routine and adapt it to suit your personal needs.

Using liquid castile soap as shampoo can be a wonderful option for almost anyone, but it has some additional benefits for those who are struggling with scalp issues such as dermatitis, psoriasis, and dandruff, because of its moisturizing oil base and lack of sulfates. It can also be a good option for people with allergies or sensitivities to chemical ingredients found in most commercial shampoos.

Check out our brand new Liquid Castile Soap in the Soap + Shampoo Bars section of our Growing Organic Shop. This is the latest addition to our Lactosoapcillus line of all-natural probiotic and vegan soaps, and you can count on it to deliver all of the same skin-loving probiotic benefits that you have come to love. We are happy to offer four customer-favorite, all-natural scents of liquid castile soap, including “Frankincense, Tea Tree & Lavender” “Lavender”, “Patchouli”, and “Peppermint and Eucalyptus”, as well as an “Unscented” option.

If you have any questions, suggestions, or feedback, as always please don’t hesitate to reach out to us.

Happy Washing!


  1. Informative insights on the usage of liquid castile soap as a shampoo.. Good read

  2. I am interested in your product.

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