Eyebrows lose their color when the pigment-producing cells in the hair follicle slow down or stop working. This can happen gradually with age, but if it’s happening faster than expected, a handful of common causes could be behind it, from skincare products to nutritional gaps to thyroid problems.
How Eyebrow Hair Loses Its Color
Hair color comes from melanocytes, cells that produce pigment and deposit it into each strand as it grows. These melanocytes are replenished by a pool of stem cells that live in a specific zone of the hair follicle. Research from the National Institutes of Health has shown that as hair follicles age, these stem cells gradually lose their ability to move to the right location and mature into functioning pigment producers. Instead of cycling between a resting state and an active state, they get stuck in between and can no longer generate color.
This process is the same one responsible for gray hair on your head, but it can affect eyebrows independently and sometimes earlier. Because eyebrow hairs have a much shorter growth cycle than scalp hair, changes in pigment production can become visible relatively quickly. You might notice your eyebrows looking washed out or developing individual white or pale hairs before the rest of your hair shows any signs of graying.
Skincare Products That Bleach Eyebrow Hair
One of the most overlooked causes of lighter eyebrows is something sitting on your bathroom counter. Benzoyl peroxide, a common acne treatment, is a powerful bleaching agent. If you apply it to your forehead, around your nose, or anywhere near your brow area, it can lighten your eyebrow hairs over time. Cream-based formulas are more likely to cause this than face washes because they stay on the skin longer, giving the peroxide more time to break down hair pigment.
This effect isn’t universal. It tends to happen with frequent use and generous application, but if your eyebrows have turned noticeably lighter and you’ve recently started or increased your use of a benzoyl peroxide product, that’s likely the cause. The fix is straightforward: either avoid the brow area when applying, switch products, or simply wait for new growth to come in at your natural color.
Sun Exposure Breaks Down Hair Pigment
UV radiation physically degrades melanin, the pigment molecule inside each hair strand. When sunlight hits the melanin in your eyebrow hairs, it triggers a chain of chemical reactions that produce highly reactive oxygen molecules. These molecules then attack and break apart the melanin structure itself, reducing the hair’s ability to absorb and reflect light at its original color. Over weeks and months of cumulative sun exposure, this makes eyebrow hairs appear lighter, particularly during summer or if you spend a lot of time outdoors.
Unlike scalp hair, which is often partially shielded by its own density, eyebrows are thin, sparse, and fully exposed to the sun. This makes them especially vulnerable to photobleaching. Wearing sunscreen on your face offers some protection, and hats with brims can help reduce direct UV exposure to your brow area.
Nutritional Deficiencies and Premature Graying
Several nutrient shortfalls are linked to premature loss of hair color. Vitamin B12 deficiency is the most well-documented, but low levels of iron, copper, biotin, folic acid, and pantothenic acid (vitamin B5) can all contribute to hair depigmentation. These nutrients play roles in either melanin production or the health of the cells responsible for making it.
B12 deficiency is particularly common in vegetarians, vegans, older adults, and people with digestive conditions that impair nutrient absorption. Iron deficiency is widespread among women of reproductive age. If your eyebrows are lightening alongside other symptoms like fatigue, pale skin, or brittle nails, a simple blood test can check your levels. In some cases, correcting the deficiency can restore pigment to new hair growth.
Thyroid Problems and Eyebrow Changes
An underactive thyroid can cause eyebrow hair to thin and fall out, particularly in the outer third of the brow closest to your temples. This pattern is distinctive enough that it has a clinical name: the Hertoghe sign. When your thyroid doesn’t produce enough hormones, it disrupts the normal hair growth cycle. One theory is that this hormonal imbalance leads to a buildup of certain compounds between cells, triggering inflammation that damages hair follicles and the structures around them.
The Hertoghe sign isn’t one of the most common hypothyroidism symptoms, so it’s rarely the first clue. But if your eyebrows are getting lighter or sparser on the outer edges, and you’re also experiencing weight gain, cold sensitivity, dry skin, or unusual fatigue, thyroid function is worth investigating. A thyroid panel is a routine blood test your doctor can order.
Vitiligo and Autoimmune Pigment Loss
Vitiligo is a condition where the immune system attacks melanocytes, destroying the cells that produce pigment. When this happens in hair follicles, it causes white patches of hair, a phenomenon called leukotrichia. In a study of vitiligo patients with white hair involvement, eyebrows were affected in about 8.5% of cases, making it less common than scalp involvement but far from rare.
Vitiligo-related eyebrow lightening usually appears as a distinct patch of completely white hairs rather than an overall fading. You might also notice depigmented patches on the skin underneath or elsewhere on your body. The condition is progressive in many people but not painful, and treatments exist that can help repigment both skin and hair in some cases.
What to Look For
The pattern of lightening tells you a lot about the cause. Gradual, even fading across both eyebrows is most consistent with aging, sun exposure, or nutritional factors. Lightening concentrated on the outer third points toward thyroid issues. A sharp patch of pure white hairs suggests vitiligo. And if the timing lines up with a new skincare product, benzoyl peroxide bleaching is the simplest explanation.
If you’re also losing hair from your scalp, body, or eyelashes at the same time, that pattern suggests a systemic cause like a hormonal imbalance, autoimmune condition, or nutritional deficiency rather than something purely local. A doctor evaluating eyebrow changes will typically ask about hair loss in other body areas, review your medications and skincare routine, check for skin changes, and may order blood work to screen for thyroid function and nutrient levels.
For lightening caused by external factors like sun damage or skincare products, the color returns on its own once the cause is removed and new hairs grow in. For age-related graying, the change is permanent. For medical causes, treating the underlying condition can sometimes restore pigment to new growth, though results vary depending on how long the problem has been present and how much damage has occurred to the pigment-producing stem cells.