We know that stress is part of our lives. But when it becomes chronic, it stops being a simple psychological inconvenience and becomes a real biological disruptor. Among its primary targets: our hair. If you feel like you're losing handfuls of hair after an intense period of rush or emotional shock, it's not a coincidence. It's the result of a silent biochemical war where one hormone plays the role of the main suspect: cortisol.

Understanding this mechanism is the first step to reversing the trend. A deep dive into your hair follicles.

The hair cycle: a precise biological clock:

To understand the impact of stress, we must first remember that our hair does not grow continuously. It follows an immutable cycle, divided into three main phases:

1. The anagen phase: This is the period of active growth. It lasts several years and concerns about 85% of our hair at any given moment.

2. The catagen phase: A short transition phase (a few weeks) during which hair stops growing.

3. The telogen phase: The resting phase, lasting a few months, at the end of which the hair naturally falls out to make way for a new cycle.

Normally, this rotation is perfectly orchestrated. But chronic stress sabotages this entire organization.

Cortisol: the shadow saboteur:

In a stressful situation, our body secretes cortisol, often called the "stress hormone". In small doses, it helps us react. In constant excess, it becomes toxic for the body, and particularly for the scalp.

Cortisol acts as a permanent alarm signal. For the body, survival becomes a priority, and survival does not depend on the beauty of the hair. The metabolism will therefore cut off resources to functions deemed secondary.

Forced standby: Excess cortisol prematurely pushes a large number of hair follicles from the growth phase (anagen) to the resting phase (telogen). This is called telogen effluvium. Three to four months after the peak of stress, all these hairs fall out at the same time.

Tissue degradation: Cortisol alters the production of essential proteins such as collagen and elastin around the bulb. The result? The follicle suffocates and weakens.

Nutrient restriction: Under stress, blood vessels constrict (vasoconstriction). Nutrients and oxygen essential for keratin production no longer reach the root.

Breaking the vicious cycle:

Stress-related hair loss is particularly insidious because it creates a second level of anxiety. We stress about losing our hair, which releases even more cortisol, which aggravates alopecia.

Fortunately, this process is not irreversible. Unlike androgenetic alopecia (which is hereditary), telogen effluvium related to stress is a transient state. The follicle is not dead; it is simply "dormant".

To restart the machine, the approach must be twofold:

On the one hand, it is essential to lower overall cortisol levels (through sleep, micro-nutrition, or daily stress management). On the other hand, it is necessary to stimulate the scalp locally to awaken dormant bulbs, recreate a healthy environment, and boost microcirculation so that the hair regains all the energy necessary for its reconstruction.

Taking care of your hair often begins by listening to what our body is trying to tell us.