Can grey hair be turned back?

If fortune favors us, we are all destined for the fate of graying hair. However, there exist individuals who do not experience this phenomenon, known as gray goddesses and silver foxes. For those who are interested, researchers have discovered a few leads on how to prevent and even reverse age-related graying. It is possible that some of these options have been available for decades.

If an individual is over the age of 30 and has not yet experienced graying hair, it may be due to their genes. In identical twins, it is uncommon for one twin to have gray hair while the other does not. However, if one lives a long life, they will eventually earn the silver medal of gray hair. Unless, of course, they preempt the graying process by keeping the melanocytes, the cells that color hair, alive and well. The death of melanocytes is one of the factors that causes hair to turn gray as one ages. The entire hair follicle is damaged by a process called oxidative stress, and anything with the word "stress" in its name cannot be beneficial.

Melanocytes produce melanin pigment to keep hair dark, but they also produce hydrogen peroxide as a byproduct. While having hydrogen peroxide in one's hair is acceptable when young, as one ages, they produce fewer antioxidants to neutralize it. Consequently, the large amount of hydrogen peroxide in hair mutates DNA and damages cells, leading to gray hair. The byproduct of making melanin destroys the very cells that create it. Researchers in the United Kingdom and Germany are working on ways to prevent hydrogen peroxide buildup around these cells. Their interventions currently work in a petri dish, but their goal is to break down hydrogen peroxide and prevent oxidative stress from damaging hair cells. They have discovered an amino acid, L-methionine, that does precisely that. Exposing hair cells to L-methionine works as long as it exceeds the amount of hydrogen peroxide floating around. In the future, with the approval of a healthcare professional, individuals may be able to take L-methionine pills to maintain their hair color.

If an individual is already gray, there may still be a way to reverse it. This time, it is not about keeping melanocytes alive, but rather keeping them moving. Melanocytes begin as stem cells that move back and forth inside each strand of hair across the bulb, the follicle, and the bulge right above it. The location of melanocytes determines if they can produce color or not. Chemical signals help melanocyte stem cells turn into color-producing melanocytes, and melanocytes only come into contact with these signals in certain parts of each strand of hair, such as the bulb. When melanocytes travel down to the bulb, they become color-producing cells. Then these cells travel back to the bulge to regenerate, losing their color and starting the process all over again. However, as one ages, melanocytes do not move around as much as they used to. They get stuck in the bulge, so they cannot access the proteins that would otherwise activate them to create pigment, leading to gray hair. Researchers have discovered that dislodging melanocyte stem cells from their rut may help them differentiate into pigmented melanocytes, potentially reversing graying.

Melanocyte differentiation has been considered as a way to add color back to hair before. In 1986, a study was published inspired by treatments for patients with vitiligo, a depigmentation of the skin and hair that is not necessarily from advanced age. One vitiligo treatment, called PUVAsol, uses UV light and chemical therapy to restore pigment. The chemical part can be consumed two hours before noon, and then, when midday comes along, patients soak up the sun's rays for 10-15 minutes. While researchers are not entirely sure how this treatment restores color, one hypothesis is that it has to do with helping melanocytes move around, which makes sense given the more recent information we have about how important melanocyte movement is for pigmentation. PUVAsol was initially used as an effective treatment to add color back to the skin and hair of vitiligo patients. Years later, the treatment was extended to people who did not have vitiligo to see if it could add color to hair that had lost pigment for other reasons. It worked for most participants, including those with and without vitiligo diagnoses, and the results persisted for months.

More research is necessary to understand why PUVAsol does not work the same way for everyone. However, with the progress being made in our understanding of melanocyte longevity and movement, it may just be a matter of time.