What can cause hair to become porous?

Hair porosity refers to the hair's ability to absorb moisture and can be affected by various factors. Chemical processes such as coloring, perming, or relaxers are significant contributors to hair becoming porous. These processes involve altering the hair's molecular structure, which can compromise the cuticle—the outer protective layer of the hair shaft. When the cuticle is damaged or lifted, it allows for increased absorption of moisture but decreases the hair's ability to retain it, leading to porous hair.

Coloring treatments, for example, often use strong chemicals to open up the hair cuticle to allow color to penetrate. Similarly, perming and relaxing involve the use of chemicals that reshape the hair structure. This can lead to weakened or compromised cuticles, making hair more porous and susceptible to damage, dryness, and frizz.

In contrast, while excessive shampooing, environmental exposure, and certain hairdrying techniques can affect hair health, they do not specifically alter the structural integrity of the hair to the same extent that chemical processes do.