Guru Kate: Where does gray hair come from?

Midterms! Well, the stress that they produce anyway. This stress leads to oxidative stress, the primary cause of graying hair. Hair without oxidative stress or artificial dyes is colored by concentrations of melanin, the pigmented compound in your skin that protects it from UV light. The type and amount of melanin determines if you have blond, red or brown hair.

Cells called “melanocytes” generate melanin. A study published in 2006 in the Journal of the Federation of American Societies for Experimental Biology (FASEB) identified four main factors in gray hair production.

Brace yourself, this part involves some scientific jargon, but we can make it through this together.

1) Oxidative stress — this is the primary cause of graying hair. It essentially means that there are reactive compounds (reactive oxygen species, or ROS) that bounce around the DNA in your hair like a pinball. This disturbs the DNA bonds and renders the melanocytes useless. Without melanocytes, we have no melanin, and therefore no color in the hair.

2) Fewer melanocyte growth factors and oxidative stress-protectors — if your hair stops producing melanocytes to begin with, those cells can’t produce melanin. Boom.

Now about those oxidative stress-protectors. As organisms that breathe oxygen, we have to be ready to detoxify the ROS compounds that come with the whole oxygen package. For that, we have oxidative stress-protection pathways. However, if these pathways break down or slow down, the oxidative stress pops right back up. These pathways stray when we stress or age.

3) Mitochondrial DNA damage, especially in previously dyed hair — mitochondrial DNA is not as well protected as regular cellular DNA contained in a nucleus, so it is more vulnerable to chemical damage. Specifically, this damage can occur after someone has dyed their hair. As you may remember from high school biology, mitochondria are responsible for generating energy for the cell. So, if melanocytes can’t generate energy, they can’t produce melanin.

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4) Susceptibility of the pigmentary unit to exogenous oxidative damage — exogenous means “outside.” So while the other factors had to do with how you treated your body in a perfect environment, exogenous oxidative damage considers the type of pollutants your expose your hair to on a daily basis. An example of an exogenous oxidative agent is cigarette smoke.

Cigarette smoke is also an endogenous (inside the body) oxidative agent as it stresses many systems in the human body. Yet another reason to quit that habit.

All four of these things occur with two inevitable factors of life: stress and aging. During exams, make time for yourself to relax and enjoy life. While gray hair may seem like just a cosmetic problem, it can signal a need to think about your physical and mental health and life choices.