The pH of the scalp and its natural protection
Our scalp is a special type of skin, with sebaceous and sweat glands covered in hair. The sebum and sweat secreted by these glands create a protective mantle called the "protective acid mantle," with an acidic pH of approximately 5.5. This mantle acts as a protective layer on the outside of the epidermis and serves as a barrier against bacteria, viruses, and other potential contaminants ( Schmid - Wendtner and Korting, 2006).
It is therefore important to maintain the balance of this protective layer. Many factors can interfere with the delicate balance of this protective acid mantle, such as products that come into direct contact with the scalp, such as solid shampoo.
It is important to use a solid shampoo with the same pH as our scalp, that is, a pH lower than 5.5 ( D'Souza & Rat hi , 2015, Gavazzoni Dias, de Almeida, Cecato, Adriano, & Pichl er , 2014).
The different types of hair x
When it comes to hair, it is negatively charged. It is recommended to have an isoionic point for hair when washing with a solid shampoo. And this isoionic point is reached at a pH value of 5.5 ( Robbin s 2002).
If we want to respect the scalp and hair, it is recommended that the solid shampoo have a pH between 4.5 and 5.5, according to dermatologists and scientific studies. The pH of the solid shampoo can vary slightly depending on the hair treatment and hair type. For example, it is ideal to have a pH of 4.5 for colored hair, and the pH values should be adjusted depending on the extent of damage to the hair caused by the environment and other conditions.
The composition of a solid shampoo
A solid shampoo bar is primarily composed of surfactants and additives. Solid shampoo bars should not contain too many surfactants. Too much surfactant could lead to problems such as:
- Deregulation of sebum production (dry ends, oily roots for example)
- Itchy scalp
- Greasy and dull hair
