Your hair color is basically determined by genetics, but the environment plays a role. Different genes turn on and off as you age impacting your hair color and also the age at which your hair starts to turn grey or white. Exterior influences on hair color include diet, weather, and toxins. Severe malnutrition will make your hair lighter. The sun makes hair lighter while it makes your skin darker. One anti-cancer drug, imatinib, has been found to reverse the hair greying process. The mechanism for why imatinib does this is not well understood, and the drug has so many serious side effects that it’s not practical to consider using it as a treatment for greying hair.
Grey and white hair happen when the melanocytes in your follicles produce less and less melanin and then stop altogether. We don’t know why your follicles decide to stop producing melanin or why some follicles stop but adjacent follicles don’t stop. Some people have hair that starts to turn grey very late in their seventies or eighties while other turn prematurely grey before the age of 25.
While hair color ranges from the whitest white found in albinos to the blackest blue-black, people have been also trying to change their hair color for thousands of years. There is evidence of Ancient Greeks using all kinds of lotions and potions to lighten their hair. Hair color, historically, could denote status, rank, lineage, job, and a host of other things in the same way that hair styles had and have cultural significance.
There is still a lot we don’t know about hair, but fortunately, we at least know enough to treat hair loss in a meaningful way.
This concludes Part 3. In Part 4, we will start discussing hair replacement therapies and how we can help you with hair loss.