The shampoo cleanses by separating the sebum from the hair. Sebum is an oil secreted by the sebaceous glands that, in turn, is expelled to the outside by the hair follicles (invaginations in the dermis). The sebum is easily absorbed by the hair, forming a protective layer. Sebum protects the hair’s protein structure from external damage, but in reality it tends to trap dirt, scalp scales and products that are usually added to the hair (perfumes, fixatives, gels, etc.). The surfactants in the shampoo separate the sebum from the hair, washing the dirt with it.
Although both soap and shampoo contain surfactants, soap mixes with grease with too much affinity, so if it is used to wash hair, it removes too much sebum. The shampoo uses more balanced surfactants so as not to remove too much sebum.
The chemical mechanism that makes shampoo work is the same as that of soap. Healthy hair has a hydrophobic surface to which lipids adhere, but which repels water. Fat is not washed away, so you cannot wash your hair with water alone. When shampoo is applied to wet hair, it is absorbed into the surface between the hair and the sebum, and the surfactants in the shampoo help separate the sebum from the hair. The fat is emulsified with the shampoo and water, and this is washed away in the rinse.
The composition of the shampoo
Shampoo formulations seek to maximize the following qualities:
- Easy rinsing
- Good finish after washing hair
- Minimal skin and eye irritation
- Do not damage the hair
- Low toxicity
- Slightly acidic pH (to avoid hair thinning)
Anti-hair loss shampoos, are they effective?
Today, the market offers many products, such as shampoos, lotions, and oils that claim to be successful in preventing hair loss.
It is recommended, as a general rule, that the moment hair loss is detected, a consultation with a hair medicine specialist is consulted to identify the reason or cause of the hair loss or the state of alopecia in case of it being presented.
The follicular root is a structure of the hair follicle that is located 3-4 mm below the skin of the scalp. The external application of any cosmetic (shampoo, hairspray, dye, gel, etc.) does not penetrate far enough to the follicular root to exert the effect. Therefore, anti-hair loss shampoos do not work to stop hair loss, unless alopecia is associated with excess seborrhea or the presence of dandruff. In these cases, the special shampoo would act to clean and oxygenate the scalp, locally, and collaborate with the anti-hair loss medical treatment prescribed by the hair medicine specialist.