By Jc of The Natural Haven
This post comes courtesy of a reader’s question. Baking soda was for a time a popular alternative to conventional shampoos but the tide began to turn as naturals began to seek out low pH products. There are two sides to the baking soda story and here are the facts for you to weigh out
Pro: Shampoos contain surfactants which remove oil from skin and hair and cause irritation. For example a clarifying shampoo rich in SLS can be very irritating even within the ideal pH range of 4-7. Although pure baking soda has a higher pH, it may not be as irritating as it is not cleaning by removing oil. Soap and shampoo bars also have an alkaline pH and some naturals will find them gentler than shampoos.
Anti: There is a relationship between high pH and skin irritation. Although some shampoos can be irritating, switching to a different one may be a solution. Baking soda at pH 10 is likely to irritate skin in some individuals because of the pH.
2. Hair damage
Pro: Skin and hair only changes mildly when exposed to alkaline soap or baking soda. It will also normally recover back to normal unaided quite quickly within 45 minutes to 3 hours (British Journal of Dermatology, Volume 76, Issue 3, pp 122-125, 1949). Although shampoo is within the pH range of 4-7, it does contain negative charges from surfactants which may lift the cuticle. Whether you choose to use shampoo or baking soda, a hair conditioner is useful to correct this potential damage.
Anti: Outside the pH 4-9 range hair can experience structural changes (for examples cuticle lifting externally and some changes to the inner fibre) (J Soc Cosmet Chem, pp 393-405, 1981). Although no study specifically shows that this happens when baking soda is used, it is a possible outcome.