|Gray hair happens to people at some point in their lives although the first sight of it is usually met with some concern. / Photo by Roman Samborskyi via 123RF|
Gray hair happens to people at some point in their lives although the first sight of it is usually met with some concern. Most will consider it a sign of aging but the process of hair changing from a darker color to gray or white can also happen prematurely in people who are still in their 20s or 30s.
Some anecdotal evidence has associated premature hair graying to stress. How it happens or if such is true is not widely understood until a recent study from Harvard University. The scientists found evidence to support that stress does turn hair prematurely gray. They attributed it to the sympathetic nervous system that is known for activating the body’s response to danger called fight or flight.
Fight-or-Flight Response and Premature Graying
Ya-Chieh Hsu from Harvard University’s Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute explained that when a person is under stress, their sympathetic nerve becomes highly activated. Supposedly, such a survival mechanism is a good thing because it prepares the body to either flee the threat or fight in case of danger. It also represents the quick response our ancient ancestors used when they were faced with danger in their environment. The fight-or-flight response happens through the noradrenaline hormone that is responsible for raising the blood pressure, breathing rate, and heart rate. When the threat is gone, it takes another 20 to 60 minutes for the body to return to its original state.
Yet, the same noradrenaline can be bad for the melanocyte stem cells (MeSCs) found in the bulge of the hair follicle that also determines the hair color. These cells normally deplete as the person ages, thus turning hair gray or white because there is depletion of pigment. In an experiment conducted by the team using mice, excessive noradrenaline was discovered to speed up the hair graying process.
The Fast Depletion of MeSCs in Mice
During their experiment, the team put mice in three different types of stress using established standard protocols—injecting a chemical to activate the pain fiber of the mouse, making rapid changes between dark and light, and cage tilting. The scientists also observed the changes in all lab mice.
Hsu said that stress has always been associated with an increased level of the hormone cortisol in the body so they first thought that cortisol plays a role in the hair graying process. Surprisingly, the hair of the mice still turned gray despite removing the adrenal gland that helps produce cortisol. They also hypothesized that stress causes the immune system to attack the cells that produce the pigment. But this theory is also a dead end because even when mice lack immune cells, they still undergo the hair graying process. As the team eliminated the two possibilities, they focused on the sympathetic nervous system.
The team said that acute stress or the flight-or-fight response harms the body by causing permanent depletion of the stem cells. Hsu said that when they started the study, she was already expecting that stress is not good for the body but the damaging effect of stress that they discovered was beyond what she expected. All pigment-producing stem cells were lost after only a “few days.” The moment these stem cells are gone, it is impossible to regenerate the pigment anymore, causing permanent damage.
Lead author Bing Zhang also shared that to go from the highest to the smallest level of detail in their study, they collaborated with other scientists with different disciplines to help solve the biological question. One of their collaborators was Isaac Chiu, whose studies focus on the relationship between immune and nervous systems.
The researchers noted that their findings can help shed light on the broader effects of stress in the tissues and organs of the body. It can also serve as a groundwork for other researchers who want to block or modify the harmful effects of stress.
The UK’s Mental Health Foundation shared that out of 4,619 sample size, 74% of people have felt so stressed they are unable to cope or have felt overwhelmed. As to the behavioral effect, 46% reported that they ate unhealthily or too much because of stress, 29% said they started or increased their drinking, and 16% said they started or increased their smoking. As to the psychological effects, 51% reported feeling depressed, 61% anxious, 16% had self-harmed, 32% had suicidal feelings and thoughts, and 37% reported feeling lonely or stressed as a result of stress.
A Worldwide Survey of People Affected by Gray Hair
In an earlier study that appeared in the British Journal of Dermatology, researchers from cosmetics company L'Oréal assessed 4,192 healthy female and male volunteers with natural hair color. They studied the hair color according to geographical or ethnic origin, gender, and age. The result showed that 74% of people between 45 and 65 years old were affected by gray hair with a 27% mean intensity. Men concealed significantly more gray hair compared to women. African and Asian descent in the study showed less gray hair compared to participants of Caucasian ethnic or geographical origin.
Database company Statista also showed the size of the global haircare market from 2012 to 2025 (forecasted). The figure refers to the value of total sales of hair care products globally at retail selling price or the total money spent by consumers on hair care products worldwide: 2012 (US$75 billion), 2013 (US$77 billion), 2014 (US$79 billion), 2015 (US$81 billion), 2016 (US$83.36 billion), 2017 (US$85.69 billion), 2018 (US$87.91 billion), 2019 (US$90.19 billion), 2020 (US$92.52 billion), 2021 (US$94.92 billion), 2022 (US$97.38 billion), 2023 (US$99.9 billion), 2024 (US$102.49 billion), and 2025 (US$105.14 billion).
Anti-Aging Industry: Statistics
Meanwhile, the size of the anti-aging market worldwide in 2015 was US$140.3 billion and is expected to reach $216.52 billion in 2021, Statista added. The world’s leading cosmetics brand today is L'Oréal, which was valued at $13 billion in 2016 followed by Gillette with $7.2 billion annual revenue.
The amount of pressure that people experience to have a youthful appearance is everywhere and it is influential. From digital media to print, television, and movies, having a youthful and attractive physical appearance is flaunted as an important factor for success. This gives fuel to the anti-aging industry that generates billions of revenues each year. But beyond just enhancing the outer appearance, the Harvard study focuses on relieving stress to prevent premature graying of hair.