Many people use their cold process soap as a shampoo bar as well. But hair is different than skin, so you need to do a few things differently in order to have the best results. Most soap makers recommend:
- Formulating your recipe differently - both in terms of the oils chosen, but in the additives and superfat percentage
- Using a vinegar or citric acid rinse
- Knowing that some people's hair just doesn't work well with real soap - and being o.k. with going back to a standard surfactant-based shampoo. There are so many variants like the hardness of the water where you live and your particular hair type, that they just don't work for everyone.
RECIPES
First, for the best results on your hair, there are a few changes you can make to your regular soap recipe that will help your soap work better on hair. Castor oil makes great shampoo, as do the softer oils like avocado, canola and almond.
Here are three recipes to get you started. Feel free to customize them or use similar oils that you may have on hand. (For example you can easily substitute palm kernel for the coconut, or rice bran for the olive, or lard for the palm.)
I list the percentages as well as the ingredients to make a 2 lb batch of soap. They can be scaled up or down according to your needs.
Note: I've calculated the superfat/lye discount percentage at 6% for these recipes. Some people prefer a low (3% or so) superfat in their shampoo bars, others prefer a high (10-15%) superfat in their recipes. Give 6% a try and then adjust up or down depending on your preference. Be sure to always run your recipe through a lye calculator! These recipes will still all probably take at least 48 hours to harden in your soap mold.
Basic, mild shampoo recipe
- 25% coconut oil
- 25% olive oil
- 20% castor oil
- 15% canola oil
- 15% palm oil
- 5.8 ounces coconut oil
- 5.8 ounces olive oil
- 4.6 ounces castor oil
- 3.5 ounces canola oil
- 3.5 ounces palm oil
- 3.2 ounces sodium hydroxide
- 6.4 ounces water
- 3/4 tsp of salt (to make the soap get harder quicker)
- 1 tsp of sugar (to boost the lather)
- 1 ounce of fragrance or essential oil blend
- 30% coconut oil
- 25% olive oil
- 25% castor oil
- 10% palm oil
- 10% canola oil
- 6.9 ounces coconut oil
- 5.8 ounces olive oil
- 5.8 ounces castor oil
- 2.3 ounces palm oil
- 2.3 ounces canola coil
- 3.2 ounces sodium hydroxide
- 6.4 ounces water
- 3/4 tsp of salt (to make the soap get harder quicker)
- 1 tsp of sugar (to boost the lather)
- 1 ounce of fragrance or essential oil blend
- 25% coconut oil
- 20% olive oil
- 20% castor oil
- 10% canola oil
- 10% avocado oil
- 10% palm oil
- 5% jojoba
- 5.8 ounces coconut oil
- 4.6 ounces olive oil
- 4.6 ounces castor oil
- 2.3 ounces canola oil
- 2.3 ounces avocado oil
- 2.3 ounces palm oil
- 1.2 ounces jojoba
- 3.1 ounces sodium hydroxide
- 6.2 ounces water
- 3/4 tsp of salt (to make the soap get harder quicker)
- 1 tsp of sugar (to boost the lather)
- 1 ounce of fragrance or essential oil blend
You'll want to make sure to add the salt and the sugar to the lye water. The salt helps the soap to get harder quicker and the sugar helps boost the lathering ability of the soap.
RINSE
Because of the high ph of cold process soap, most people use a slightly acidic rinse on their hair after using a shampoo bar. The high ph raises the cuticle of the hair follicle - making it more prone to damage. The rinse helps lay it back down.
You can make the rinse out of either:
- 1 cup vinegar (apple cider or white) to 2 cups water or
- 1 tbsp. citric acid powder to 3 cups water


