An effective shampoo should:
Cleanse the hair: Shampoo helps to remove dirt and soil from the hair and scalp. Sebum, dust and styling products build up on hair over time, and shampoo is needed to remove them, without being too harsh and removing beneficial lipids on the hair.
Close the cuticle: The cuticle is the outermost layer of the hair and resembles roof tiles. A good shampoo will make sure that cells of the cuticle are laid flat, thus protecting the underneath layers from damage.
Balance pH of hair: Hair needs a slightly acidic pH in order for the cuticle to be closed down, and to decrease the static electricity which causes tangles and damage to the hair. It’ a good idea to use PH strips to test product acidity levels. Body soaps have alkaline PH however, hair soaps should have a more acid or neutral PH.
Contain a preservative: If a homemade mixture is left at room temperature for more than a few days, it is very likely to show microbial growth in it. You can use rosemary or tea tree essential oils as natural preservative or try Germall Plus or Optiphen Plus which are broad-spectrum and water-soluble if you are concerned or need the product to last longer. Bar soaps typically don’t need a preservative since the pH is too high for bacteria to grow.
Include an emulsifier or solubilizer or surfacant: If mixing oil and water – two ingredients that are incompatible without an emulsifier or solubilizer or surfactant. Without these additions, it will leave your hair feeling (and looking) rather oily after using it. It’s best to get silicon free and paraben free ones if possible.
DIY haircare recipes are commonly based around the following ingredients:
- Castile soap
- Coconut milk
- Cold process soap bars
- Baking soda
These ingredients should be used with care. If a DIY recipe is not preserved or stored correctly, it can lead to bacteria, yeast and mould proliferating in them causing infections.
Castile soap will definitely cleanse the hair, but the pH of castile soap is very high (or alkaline – the opposite of acidic), around 9 -10, which is completely unsuitable for hair. When hair is treated with an alkaline product, it will leave the cuticle cells open and prone to damage. Hair with an imbalanced pH will also be a lot more prone to breaking and tangling. Offset this with a nourishing hair oil or D Panthenol added.
Coconut milk on its own, (without soap added), will not cleanse the hair. The pH of coconut milk is close to neutral (around 6.0-7.0), which is too high for the hair. Coconut milk will provide some vitamins and moisturization to the hair, but it won’t close the cuticle or balance the pH of the hair. Consider using coconut soap base instead.
Baking Soda: Baking soda can act as a degreaser, so it will remove some of the oils from the hair, but it won’t do it very gently. A solution of baking soda in water has a very high pH, (about 9.5), which is too high for the hair, and can irritate your scalp. It will not close the cuticle and will eventually leave your hair brittle and prone to breakage. Citric acid can be used as a PH balancer.
Body soap bars: Soap bars are very similar to liquid castile soap, but they have a solid form. The chemistry behind these two products is the same and they both have a pH which is way too high for the hair. Soap bars will clean the hair effectively, but since they won’t close the cuticle down, or balance the pH of the hair, it will leave the hair dry, tangled and prone to further damage.
Selecting Natural Oil Ingredients
When it comes to choosing natural oils, there are hundreds of options. The right oil will largely depend on what your hair type needs. Start by identifying what type of hair you have and any specific hair needs such as increased moisture, less oil, or colour protection.
Coconut oil results in harder soap bars than olive oil, but olive oil tends to be more nourishing making it ideal for dry hair or damaged hair. Sweet almond oil is great for colour-treated hair thanks to its natural colour-staying properties.
Avocado oil helps tame flyaways and is particularly suited for curly hair. Jojoba oil is known to mimic the production of sebum. Using this oil in your homemade shampoo bar can help minimize oil production for people who have oily hair.
Most shampoo bars also incorporate castor oil because it helps increase lather. Since this oil can cause sticky build-up, it’s best to keep the concentration to below 10 percent of your total ingredients.
Tallow oil, or the vegan-friendly alternative of palm oil, both have a long shelf life that makes them suitable for soap and shampoo bars. These oils help prevent decomposition and preserve the integrity of your shampoo bar so you can use it longer than alternatives. For our shampoo bar recipe, we’ll use a combination of these natural oils.