Chronic stress has been linked to hair loss for years, but now researchers are understanding how.
Hair growth happens in a cycle consisting of several different stages. At any one-time, different hairs on a person’s head are in different phases. There are four distinct phases, according to a 2017 study in the journal Clinical, Cosmetic and Investigational Dermatology.
- Anagen — the growth phase: 90% of follicles are in this stage at any one time, and it can last as long as six years on the scalp before entering the next stage. In this phase, hair follicles continually push out new hairs that continue to grow until they’re cut or fall out.
- Catagen — the transition phase: This short, 10-day stage sees the hair follicles shrink as blood supply to the cells is cut, slowing down hair growth. Around 1% of follicles are in this stage.
- Telogen — the resting phase: Around 9% of follicles are in this stage at any one time, and it lasts around three months. During this phase, the hair follicles remain inactive.
- Exogen — the shedding phase: This is the final stage in which individual hairs fall out.
When stress causes disruption to this cycle, more hairs move into the telogen phase, causing an increase in hair shedding and overall thinning, said Eva Proudman, a consultant trichologist, or specialist in hair-related diseases.
Proudman also talked about how chronic stress has been linked to hair loss for years and commented on the 2021 study in mice, published in the journal Nature, that found a potential mechanism.
In the Nature study, researchers subjected mice to stress, which increased the animals’ levels of cortisol, the body’s stress hormone. Higher levels of cortisol meant the mice’s hair follicles remained in an extended resting stage, where the follicles remained inactive. When hair follicles are inactive, hair doesn’t grow, yet the mice continued to shed hair at their normal rate. Increased cortisol also prevented the cells beneath the hair follicle (dermal papilla) from secreting a molecule called GA56. GA56 activates hair follicle stem cells, encouraging new growth.
Because the Nature study was in mice, it’s not clear if the same mechanisms explain why stress may lead to hair loss in humans. “But it’s clear there is a link between stress and hair loss”, said the specialist in hair-related diseases
According to the Mayo Clinic, if a person experiences high stress levels, the person may notice that more hair is falling out or that fewer hairs are growing back. Both men and women can be affected with the stress-related hair loss.
The Mayo Clinic described the types of hair loss associated with high stress levels as:
In telogen effluvium (TEL-o-jun uh-FLOO-vee-um), significant stress pushes large numbers of hair follicles into a resting phase. Within a few months, affected hairs might fall out suddenly when simply combing or washing your hair.
Trichotillomania (trik-o-til-o-MAY-nee-uh) is an irresistible urge to pull out hair from your scalp, eyebrows or other areas of your body. Hair pulling can be a way of dealing with negative or uncomfortable feelings, such as stress, tension, loneliness, boredom, or frustration.
A variety of factors are thought to cause alopecia areata (al-o-PEE-she-uh ar-e-A-tuh), possibly including severe stress. With alopecia areata, the body’s immune system attacks the hair follicles — causing hair loss.
Stress and hair loss don’t have to be permanent and if you get your stress under control, your hair might grow back!
#MNHD Editorial Staff