What Are White Hairs Called? The Science and Facts Behind Gray and White Strands

It's a common sight as we age: strands of hair that have transitioned from their original color to shades of gray and eventually, pure white. Many of us casually refer to them as "gray hairs" or simply "white hairs." But is there a more specific scientific or even common terminology for these changes in hair pigmentation? Let's dive into the fascinating science behind why our hair turns white and what these hairs are technically called.

The Science of Hair Color: Melanin is Key

To understand why hair turns white, we first need to understand how it gets its color in the first place. Hair color is determined by a pigment called melanin. There are two main types of melanin that contribute to hair color:

Eumelanin: This type of melanin is responsible for brown and black hair colors. The more eumelanin present, the darker the hair.
Pheomelanin: This pigment is responsible for red and blonde hair colors.

These melanin pigments are produced by specialized cells called melanocytes, which are located within hair follicles. As new hair cells grow, they incorporate melanin from the melanocytes, giving the hair its characteristic color.

Why Does Hair Turn Gray or White?

The process of hair graying and whitening is primarily due to the natural decline in the activity of melanocytes over time. As we age, these pigment-producing cells begin to produce less melanin, and eventually, they may stop producing melanin altogether. This leads to hair strands growing with reduced pigment, resulting in:

Gray Hair: This occurs when melanocytes are still producing some melanin, but at a reduced rate. The hair shaft becomes a mix of pigmented and unpigmented (white) hairs, creating the appearance of gray. The more unpigmented hairs that appear, the lighter the overall gray shade.
White Hair: This happens when melanocytes completely stop producing melanin. The hair follicle then produces hair strands that are devoid of pigment, appearing pure white. It's important to note that truly white hair is essentially colorless hair that reflects light, making it appear white.

What Are White Hairs Called?

While we commonly use the terms "gray hair" and "white hair," there isn't a single, distinct scientific or colloquial term that specifically differentiates between a fully white strand and a very light gray strand in everyday language. Both are the result of reduced or absent melanin production.

However, in scientific contexts, the phenomenon is referred to as canities. Canities is the medical term for the graying or whitening of hair.

So, when someone refers to their "white hairs," they are generally speaking about strands that have lost all or nearly all of their pigment, appearing white or a very light, almost translucent gray. Similarly, "gray hairs" encompass the spectrum from salt-and-pepper shades to a more uniform light gray.

Factors Influencing Graying and Whitening

While aging is the most common cause of hair graying and whitening, other factors can also contribute:

Genetics: Your genetic predisposition plays a significant role in determining when and how quickly your hair will turn gray or white. If your parents or grandparents grayed early, you are more likely to as well.
Stress: While the direct link is still debated and researched, severe or chronic stress has been anecdotally linked to accelerated graying. The theory is that stress hormones might impact melanocyte stem cells.
Nutritional Deficiencies: Deficiencies in certain vitamins, such as B12, and minerals like copper and iron, can sometimes affect melanin production.
Medical Conditions: Certain medical conditions, like autoimmune diseases (e.g., vitiligo, alopecia areata) and thyroid disorders, can sometimes lead to premature graying or whitening of hair.
Smoking: Studies have suggested a link between smoking and premature graying of hair.

The Appearance of White vs. Gray Hair

It's often a gradual process. You might first notice a few scattered white hairs amongst your colored ones, which appear as "gray." As more melanocytes become inactive, the proportion of unpigmented hairs increases, leading to a more pronounced gray look. Eventually, if all melanocytes in a particular follicle cease melanin production, you'll see a fully white hair.

It's important to understand that hair doesn't actually turn gray; rather, new hair grows in without pigment. The existing colored hair remains colored until it sheds and is replaced by a new, less pigmented strand.

In essence, what we call "white hairs" are simply hairs that have completely lost their melanin pigment, while "gray hairs" are a mixture of pigmented and unpigmented hairs, or hairs with significantly reduced pigment.

Frequently Asked Questions (FAQ)

How does stress cause white hair?

The exact mechanism is still being researched, but a leading theory suggests that severe stress can trigger a response where the body's immune system attacks the melanocyte stem cells in hair follicles. This damage can then lead to a depletion of melanocytes, resulting in hair growing without pigment.

Why do some people go completely white while others stay gray?

This is largely due to genetics and the individual rate at which melanocytes in different hair follicles stop producing melanin. Some individuals might experience a complete shutdown of melanin production in all their follicles simultaneously or in close succession, leading to all-white hair. Others might have a more gradual or uneven loss of pigment, resulting in a gray appearance.

Can gray hair turn back to its original color?

Generally, no. Once melanocytes have stopped producing melanin due to aging or damage, their function is often irreversible. However, in some cases, graying caused by temporary factors like severe stress or nutritional deficiencies might be reversible if the underlying cause is addressed promptly.

Are white hairs stronger or weaker than colored hairs?

There is no scientific evidence to suggest that white or gray hairs are inherently stronger or weaker than pigmented hairs. The structural integrity of the hair shaft is determined by factors like protein content and cuticle health, not by the presence or absence of melanin.