Believe it or not, few people actually enjoy having white hair. Especially for many middle-aged individuals and young people who prematurely turn gray, they often complain about the impact of white hair on their personal image, feeling quite troubled by it. Even if it's just a few strands, white hair seems particularly noticeable on the head.
Many people can't help but wonder, can hair turn black again after turning white?
In a simple answer, yes—it can turn black again, for example, through dyeing.
However, many may find this "smart aleck" answer unsatisfactory and seek to learn more about treatment methods. So today, let's delve into the matters of hair turning black or white.
The Principle of Hair Color Change
The color of hair is determined by pigments inside the hair, mainly melanin. Black hair has more melanin, white hair has less or none, and gray hair falls in between.
Black hair (left) and white hair (right) (from reference material)
The process of melanin production is like a complex assembly line, influenced by various factors such as race, genetics, individual differences, diseases, and age.
So, why does hair turn from black to white? In a nutshell, the fundamental reason lies in the dysfunction and death of melanocytes, the melanin-producing cells, within the hair follicle pigment unit.
Specific melanocytes experience malfunctions or die directly, akin to a chicken falling ill or dying, resulting in no eggs being produced.
Many other cells play crucial roles in this process, especially melanocyte stem cells, which have the ability to create something from nothing, differentiating and transforming into new melanocytes. With factors like aging, these stem cells become "lazy," their transformation ability decreases, leading to an increase in white hair. If these stem cells are completely lost, the white hair can never turn black again.
Additionally, epithelial stem cells within the hair follicle also play a role. Their descendant cells provide a nurturing environment for the stem cells that cultivate melanocytes. If these descendant cells deplete due to certain reasons, white hair can appear.
Apart from the influence of stem cells, there are also complex mechanisms at the molecular level.
What causes hair to turn white?
Understanding the basic principles of hair color changes, let's delve into why some people experience premature graying despite their young age. From a causative perspective, there are essentially two main categories:
Physiological reasons: such as aging and genetic factors;
Pathological reasons: such as skin and hair diseases, and medication effects.
The population with white hair can be categorized into "normal white hair" and "premature white hair." Asians typically start developing white hair in their 30s, which falls under "normal white hair," with many individuals having half-white hair by the age of 50. Normal white hair is generally a normal sign of aging. On the other hand, "premature white hair" refers to white hair appearing before the age of 25, which is 10 years or more earlier than normal white hair.
For most individuals (including those with premature graying), the primary reason for white hair is physiological. An analysis of data from 467 individuals with premature graying (354 females, 113 males) spanning ages 18 to 77 revealed:
Premature graying is closely linked to family history, whether it's from the father, mother, grandparents, or siblings, indicating a strong genetic influence;
Iron deficiency can also lead to white hair;
In males, oral biotin supplements can increase the likelihood of white hair.
Furthermore, research has shown that premature graying is not significantly associated with factors like obesity, alcohol consumption, coffee intake, stress, mood disorders, or autoimmune diseases.
It must be noted that this research yielded several counterintuitive results. For instance, while it's commonly believed that emotional stress causes graying, there is currently no definitive research establishing a causal relationship between stress and white hair.
Moreover, some individuals may believe that using supplements or enhancing their nutrition can improve hair condition. However, using such products blindly and without evidence may have adverse effects. As mentioned earlier, oral biotin supplements in males can actually increase the likelihood of white hair.
So, how can one determine if their white hair is pathological?
If you are around 30 years old or older, and a few strands of white hair sporadically appear along with changes in facial texture, skin quality, or pigmentation, there's generally no need to worry about other issues.
However, if a significant portion of your hair turns white within a short period, accompanied by symptoms like hair loss, scalp whitening, or other skin manifestations, it could be due to an underlying disease. In such cases, it's advisable to seek medical advice offline to rule out any other problems. These manifestations could be indicative of conditions like alopecia areata, telogen effluvium, vitiligo, internal diseases, or drug reactions.
How can white hair be turned black?
Are there methods to turn white hair black? Here are some practical approaches:
While dyeing hair is not a medical treatment, it is an effective way to darken hair with immediate results. Scientists have discovered some promising drugs for treatment, but as of now, there are no approved medications specifically for reversing graying.
Theoretically, plucking white hair can remove it, and you don't have to worry about multiple hairs growing in its place. However, this method carries the risk of damaging the hair follicles and increasing the chance of infection.
Trimming white hair at the root is a safer option as it doesn't harm the follicles. The downside is that this is a temporary solution, as the white hair will grow back over time.
If white hair is caused by an underlying condition like alopecia areata or vitiligo, focusing on treating the primary disease can potentially improve the white hair condition once the illness is resolved.
References
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[2] The depigmentation of white hair. Link
[3] Yale K, Juhasz M, Atanaskova Mesinkovska N. Medication-induced repigmentation of gray hair: a systematic review. Skin Appendage Disord. 2020; 6(1): 1-10.
[4] Feng Z, Qin Y, Jiang G. Reversing gray hair: Inspiring the development of new therapies through research on hair pigmentation and repigmentation progress. Int J Biol Sci. 2023; 19(14): 4588.
[5] Thompson KG, Marchitto MC, Ly BCK, et al. Evaluation of physiological, psychological, and lifestyle factors associated with premature hair graying. Int J Trichology. 2019; 11(4): 153.
[6] Webmd. Facts About Gray Hair. Link. Nov 15, 2021.
[7] Kumar AB, Shamim H, Nagaraju U. Premature graying of hair: Review with updates. Int J Trichology. 2018; 10(5): 198-203.
[8] Kaur K, Kaur R, Bala I. Therapeutics of premature hair graying: A long journey ahead. J Cosmet Dermatol. 2019. Epub ahead of print.
[9] Leerunyakul K, Suchonwanit P. Asian hair: A review of structures, properties, and distinctive disorders. Clin Cosmet Investig Dermatol. 2020; 13: 309-318.
