March 4, 2025, 2:02 pm | Read time: 6 minutes
While some people find gray hair attractive, for many, it is an undesirable sign of aging. But why do some people turn gray at the age of 20 or 30? Research now shows that, in addition to genetics, oxidative stress also plays a key role. Does this finding open up new therapeutic perspectives?
Gray hair is often seen as a sign of aging. However, the causes are more complex than you might think. In addition to genetic factors and age-related changes, research is now also focusing on immune processes. Several studies are providing insights into how our body reacts to stress and infections — and what role the immune system plays in this. For example, can a simple viral infection actually lead to premature greying? FITBOOK has looked at various study results.
Overview
How Gray Hair Occurs
Generally speaking, hair graying is often a sign of aging that becomes noticeable with increasing age. The pigment eumelanin, which is usually formed in the hair roots, forms the basis for a dark hair color. This is produced by an enzymatic conversion of the amino acid tyrosine, which also serves as a building block for adrenaline.
However, the activity of melanocytes, i.e., melanin-producing cells, decreases with advancing age. As a result, less tyrosine is converted into melanin, which leads to a lack of melanin in the hair. As a result, not enough color pigments are deposited in the stratum corneum, and the hair appears grey. The process usually starts between the ages of 30 and 50 but can also begin earlier. If gray hair appears before the age of 20, it is referred to as premature graying.1
The graying of hair is surrounded by numerous superstitions and myths. While in some cultures, it is perceived as a sign of wisdom and experience, in others, it is seen as a sign of physical decline and a harbinger of aging. The origin of these assumptions often lies in old tales or legends that have been passed down through the generations. For example, it was once believed that a sudden shock or traumatic event could cause someone to turn gray overnight. This superstition was reinforced by stories such as that of Marie Antoinette, whose hair supposedly turned white the night before her execution.2
What Causes Melanocytes to Die?
As already mentioned, melanocytes, which are pigment cells, are responsible for giving hair its individual color. However, if melanocytes die off, pigments can no longer be produced, and the hair that grows back appears gray. In 2018, researchers at the University of Alabama at Birmingham investigated the question of what causes melanocytes to die off. The scientists carried out genetic experiments on mice with a predisposition to gray hair.
Gray Hair Due to the Immune System? Study with Mice Provides Clues
A central aspect of the study was the so-called MITF gene (microphthalmia-associated transcription factor). This transcription factor is a protein that plays an important role in melanocytes (the pigment-forming cells of the skin). It influences the production of certain enzymes and how different cell types develop.3 Earlier assumptions were that the loss of pigmentation in the hair — i.e., graying — was caused by the aging process and reduced melanin production. The American study, on the other hand, investigated the influence of the immune system on the pigmentation process.
To investigate the role of MITF and the innate immune system, the researchers used genetically modified mice. The researchers found that mice with a heterozygous form of the MITF gene, i.e., those that had inherited two different variants of the gene from their parents, showed an altered response to the immune system. As they produced less MITF protein, they developed gray hair more quickly — especially when their immune system was activated by experimental stimulation.4
The study thus provides evidence that the innate immune system, in particular, could play a key role in the development of gray hair. An imbalance in the immune system could cause the melanocyte stem cells to lose their function, leading to a loss of hair pigmentation — and thus to graying.
Can the Phenomenon Also be Transferred to Humans?
Although this phenomenon has only been studied in mice so far, the researchers assume that it could also occur in humans. “In a healthy person with a predisposition to graying, a viral infection could possibly be enough to trigger a decrease in melanocytes — and thus cause premature graying,” explains Melissa Harris, one of the scientists responsible, in a press release from the University of Alabama at Birmingham.5
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What Other Factors Play a Role in Gray Hair — Further Studies
However, this explanation is only one of many for the development of gray hair — and the process cannot yet be specifically influenced. In this respect, greying remains an individual factor of appearance that does not necessarily indicate old age.
Genetic factors also play a role, and external influences can accelerate the first appearance of gray hair — for example, hormonal diseases or a severe lack of nutrients due to an unbalanced diet. Stress can also have a significant influence.
Connection with Genetic Factors
A mouse study investigated the mechanisms of graying, focusing in particular on the maintenance and function of melanocyte stem cells in the hair follicle. The results showed:
- Incomplete maintenance of melanocyte stem cells: This leads to reduced melanin production and, therefore, graying.
- Deficiency in the Bcl2 gene: The Bcl2 gene (B-cell lymphoma 2) plays an important role in cell survival mechanisms, as it prevents programmed cell death (apoptosis).6 A lack of this gene can cause melanocyte stem cells to die prematurely, which accelerates the graying process.
- Mutations in the MITF gene: As already mentioned, the MITF gene codes for a central transcription factor that is crucial for the regulation of melanocytes. Mutations in this gene can influence differentiation and pigmentation within the stem cell niche and thus contribute to graying.7
Autoimmune Diseases
A review study examined various biological processes that can cause hair to turn gray earlier than usual. These include genetic factors, an imbalance between harmful and protective molecules in the body (oxidative stress), a lack of important nutrients, and possible links to certain diseases.
The results suggest that premature graying is based on a combination of several factors. While some studies consider autoimmune reactions as a potential trigger, there is as yet no clear evidence of a direct link.8
The Association Between Premature Graying and Cardiovascular Health
As part of a cross-sectional study, 6,390 men under the age of 30 were asked about their hair status and various socio-demographic and clinical characteristics using questionnaires. The results of the study indicate that the following factors may contribute significantly to premature graying.
- Smoking: Active smoking was identified as a significant risk factor.
- Genetic predisposition: A familial clustering of premature graying indicates a genetic component.
- Obesity: A high body mass index (BMI) has also been associated with an increased risk of premature graying.9