Shampoo

Fat mainly comes from the scalp

The sebaceous glands of the scalp produce sebum, which is then distributed over the fibers. Visible hair does not produce this fat itself. By accumulating, sebum can group the fibers into strands, flatten the roots and change their shine. The oily appearance therefore depends as much on its distribution as on the shape and fineness of the hair.

Washing removes part of this deposit, to which are added products and particles from the environment.

Surfactants allow rinsing of fatty substances

Water alone does not mix well with sebum. Surfactants have parts that interact with water and fatty substances; they facilitate the detachment and dispersion of residues, which can then be washed away when rinsing. The massage is mainly used to put the formula in contact with the different areas, not to mechanically strip the skin.

Foam corresponds to air dispersed in the liquid and stabilized by the formula. It accompanies washing but does not directly measure its effectiveness. A low foaming product can clean, and a second very foamy pass does not prove that it was essential. The result and comfort after rinsing are more useful criteria.

Sulfates do not judge a formula on their own

Some shampoos use sulfated surfactants, others use different systems. Their effect depends on their nature, their concentration and their association with other ingredients. A formula containing sulfates may be suitable for an oily scalp; a formula without sulfates can still irritate or leave an unpleasant feel.

The information on the bottle therefore does not replace observation. If the hair remains heavy and full, cleaning may be insufficient; if they become rough and the skin feels tight, the formula or frequency may be poorly suited. Change one setting at a time to understand what really improves your routine.

Spacing out washes does not guarantee less sebum

There is a lack of solid evidence to support that voluntarily keeping oily hair teaches the sebaceous glands to produce less. The frequency can be adjusted for length comfort, but this is not the same as demonstrated regulation of production. You don't have to endure several days of discomfort to hope to turn a corner.

A 2021 publication combined an observational study and a controlled washing study, with results favoring more frequent washings in the populations studied. It has industry links and does not represent all hair textures. Above all, it invites us to avoid an overly simple rule: washing often is not automatically bad, and washing rarely is not automatically preferable.

pH and care also influence touch

The pH affects the surface properties of the hair. Very alkaline conditions can promote swelling of the fiber and increase friction; This helps to understand why a regular soap does not behave like a shampoo formulated for hair. pH nevertheless remains one parameter among others, not a universal classification of softness.

Conditioning agents applied by a treatment can reduce friction and make detangling easier. The objective of the shampoo and treatment duo is simple: to remove what accumulates at the roots while leaving the lengths soft enough to be handled without forcing.