Those gray hairs could actually have a serious silver lining—they could be a sign that your body is working to avoid a type of cancer.
It’s one of those classic first signs of getting older: that first gray hair. Whether you welcome it or resist it, the American Academy of Dermatology (AAD) says this is a common occurrence for people in their 30s or 40s, though it can happen earlier for some. “Gray hair is a normal part of aging, and there is nothing wrong with having [it],” writes the AAD. “However, if your gray hair affects your self-esteem, you can cover it using hair dye.”
But research published in the October 2025 issue of Nature Cell Biology suggests there’s a good reason to love your gray locks. Each silver strand may serve as evidence that your body has protected you against melanoma, a serious form of skin cancer, writes a team led by University of Tokyo experts in the fields of aging, dermatology, and regenerative medicine. According to the Cleveland Clinic, melanoma is “the most invasive skin cancer with the highest risk of death.”
In this animal study, the researchers used mice to better understand how hair turns gray, and which biological processes these changes signal. In particular, the study looked at special stem cells in hair follicles that make pigment, called melanocyte stem cells (McSCs). One of the study’s authors, Emi K. Nishimura, PhD, has been previously recognized for her work in discovering these cells in both mice and humans.
The study’s scientists found that when these stem cells experience a serious type of DNA damage called a double-strand break, they switch into a different kind of cell—a pigment-making cell. In a process known as “seno-differentiation,” they are then removed from the body instead of continuing to divide. When the pigment stem cells disappear, this causes hair to turn gray.
In contrast, cancer-causing chemicals can block this protective graying response. This keeps the stem cells in self-renewal mode, paving the way for the kind of unchecked cellular growth associated with cancer.
A press release from the University of Tokyo summed up the findings: “These cells, located in hair follicles, face a critical decision under genotoxic stress: either to differentiate and exit the system—leading to graying—or to continue dividing, which may eventually lead to tumor formation.”
The researchers observed this in mice lacking p53, a protein that detects damaged DNA. Though these mice kept their dark fur after radiation exposure—an environmental stressor that would normally cause grays—their damaged cells put them at greater risk of ultimately developing cancer instead.
Though the research team notes that this “does not suggest that graying hair prevents cancer,” there’s still a valuable takeaway. Yes, you may have a few more gray hairs as the years wear on, but they could be signs that your cells are working hard to potentially protect you. And don’t forget about one of the surest way to avoid skin cancer: making sunscreen a part of your daily skin routine.
For daily wellness updates, subscribe to The Healthy by Reader’s Digest newsletter and follow The Healthy on Facebook and Instagram. Keep reading:
- This Common Vaccine Might Help Your Immune System Fight Cancer, Says New Research
- Doing This for 30 Minutes a Day Can Slow Brain Aging, New Study Says
- How to Transition to Gray Hair, with Self-Assurance: “I Tried It” (Plus, Dermatologist and Stylist Tips)
- Eating Processed Food Could Raise Your Risk of This Surprising Cancer by 41%
