Bleaching hair is a chemical process using an alkaline agent, typically ammonia, and an oxidizer like hydrogen peroxide to lighten the hair’s natural pigment. While effective at removing color, this process primarily damages the hair shaft, leading to breakage and thinning. True, permanent baldness is a rare outcome, occurring only when the chemical mixture causes a severe burn to the scalp. Most hair loss concerns after bleaching are actually a result of hair strands snapping off close to the root.
How Bleaching Damages Hair and Causes Thinning
The lightening process requires the bleach mixture to penetrate the hair shaft. This is achieved when the alkaline agent raises the hair’s protective outer layer, the cuticle. Once inside, hydrogen peroxide begins the oxidation process, dissolving the melanin granules that provide natural color. This chemical reaction also attacks the hair’s internal protein structure, which is mainly composed of keratin.
The oxidative process breaks down the protein chains and fatty acids within the hair’s inner core, the cortex. This degradation makes the hair fiber weaker and more porous, causing it to lose moisture rapidly and become brittle. Repeated bleaching sessions compound this damage, reducing the hair’s resilience and making it susceptible to snapping. When breakage occurs near the scalp, the resulting short, uneven strands create the appearance of significant hair thinning or loss.
The Difference Between Breakage and Permanent Baldness
The distinction between hair breakage and permanent baldness lies in whether the damage affects the hair shaft or the hair follicle. Hair breakage is damage to the non-living hair strand above the scalp. This is a temporary issue because the hair follicle remains healthy and continues to produce new hair, even if the strand snaps off right at the scalp line.
True, permanent baldness only occurs if the bleach causes a severe chemical burn that damages or destroys the hair follicle beneath the skin’s surface. This rare event typically results from leaving a high-concentration bleach mixture on the scalp for too long or using an excessively high-volume developer. If the burn causes scarring on the scalp, the follicle is permanently disabled and cannot grow hair again in that area. Temporary hair loss can also occur from less severe chemical trauma that inflames the follicle, but the hair usually grows back once the scalp heals.
Safe Bleaching Practices and Damage Recovery
Minimizing damage begins with careful application, such as using a lower volume developer, like 10 or 20 volume. This lightens hair more slowly but with less intensity than higher volumes. Avoid overlapping the bleach onto hair that has already been processed, as this causes cumulative damage and is a primary cause of breakage. Applying the bleach mixture to dry, unwashed hair and keeping it off the scalp helps protect the skin from irritation and potential burns.
To treat hair that is already damaged, a consistent routine of restorative care is necessary. Deep conditioning masks replenish the moisture that porous, bleached hair has lost. Protein treatments, often called bond-building treatments, strengthen the weakened keratin structure and improve elasticity, making hair less prone to snapping. Avoiding heat styling and getting regular trims also prevent further stress on the fragile strands. If a person experiences severe scalp pain, blistering, or persistent, patchy hair loss, they should consult a dermatologist immediately, as these symptoms indicate a chemical burn requiring medical attention.