Grey Hair: What a 2025 Study Suggests About DNA Damage and Pigment Loss

Grey hair does not appear simply because strands “fade” as the years pass. A study published in 2025 indicated that, when certain types of DNA damage occur, the cells responsible for pigmentation may stop renewing themselves and disappear from the follicle-preventing compromised cells from continuing to multiply.

Why does hair lose its colour with ageing?

A strand’s shade is determined by melanin made by melanocytes during the hair growth phase. These melanocytes are replenished by stem cells housed in the follicle, but with age that reserve can shrink or fail to work properly.

• Melanocytes produce the pigments that give hair its colour;
• Stem cells replace these cells in each hair cycle;
• Ageing can reduce the available reserve;
• Genetic damage can halt the ability to self-renew;
• Without enough melanin, the new strand grows in grey or white.

What did the research find about white strands?

To investigate where grey hair comes from, researchers tracked melanocyte stem cells in mice exposed to different kinds of genetic stress. When severe breaks occurred in DNA, some of these cells became permanently mature and no longer renewed themselves.

As this reserve was lost, the follicle stopped producing new pigmented melanocytes and subsequent hairs emerged without colour. Whitening therefore appeared as a visible outcome of removing potentially compromised cells-rather than as a defence created by the white hair itself.

How can this mechanism protect tissue?

The process was termed senescence-associated differentiation. Instead of remaining in the follicle and continuing to divide with damaged DNA, melanocyte stem cells lose their renewal role and are gradually eliminated.

• DNA damage triggers internal control signals;
• The compromised cell exits the stem-cell state;
• It matures and stops generating new pigment-producing cells;
• The follicle’s melanocyte reserve decreases;
• Colour is lost, but the tissue clears a damaged lineage.

What is the link between grey hair and melanoma?

The researchers noted that certain carcinogenic agents could switch off this response. Even when damaged, some cells stayed capable of self-renewal and formed cell clusters with greater potential to contribute to melanoma development.

The study published in Nature Cell Biology described whitening and the expansion of higher-risk cells as opposite outcomes under stress. This does not mean that having white strands prevents cancer, but rather that pigment loss may accompany a cell-protection mechanism under certain conditions.

What does this discovery change in hair care?

The findings were obtained mainly in mice and do not account for every case of greying in humans. Genetics, ageing, oxidative stress, smoking, health conditions and possible nutritional deficiencies may also influence when hair starts to lose pigmentation.

The research also did not produce a treatment able to prevent or reverse grey hair. Its main contribution was to show that whitening may be the visible cost of a cellular decision: giving up pigment production capacity to stop certain damaged cells from remaining active in the tissue.