Simply put: the pigment called melanin determines the color of our hair. However, as we age, our bodies produce less melanin, which results in gray hair.

Certain contributing factors, such as stress or certain health conditions, can cause many people to notice gray hair in their third decade of life.


Genetics play a role in whether hair turns gray in our 20s. Research evidence suggests that certain genes and traits are responsible for premature gray hair.

For example, the study published in 2022 in Journal of Kerman University of Medical Sciences noted that people are three to five times more likely to develop premature gray hair if their parents did the same before their 30s.


There may be a link between stress and premature graying of hair. In a study published in 2021 in eLiferesearchers found that people with gray hair were more likely to report stressful events than other people with less stress in their lives.

Health issues

Certain health conditions can cause gray hair or make gray hair look noticeable. For example, alopecia areata is a condition that causes gaps in the scalp. People with alopecia areata may develop gray hairs in areas of hair loss. Also, vitiligo, which causes loss of pigment in parts of the skin, can lead to gray or white hair.

Vitamin or mineral deficiency

Low levels of vitamins and minerals can cause premature graying. For example, some evidence suggests that a lack of the following nutrients can cause gray hair in your 20s.

Some of them are: Calcium, Copper, Ferritin, Zinc, Vitamin B12, Iron, Copper, Folic acid, Selenium. A lack of protein can also cause your hair to lose its pigment. Research has found that vegetarian diets may increase the risk of premature graying of hair. So it’s important to make sure you’re getting enough protein.


Recent survey has associated smoking with the onset of gray hair before the age of 30. In particular, smoking can cause nicotine to build up in hair follicles, which affects hair pigmentation.

The study published in 2021 in Skin Appendage Disorders found that premature graying is more common in people who smoke.

UV exposure

The sun’s UV rays are a common source of oxidative stress, free radical and antioxidant imbalance. Free radicals are harmful substances that damage our cells.

UV exposure in this way can damage the melanin in the hair follicles since the melanin absorbs the free radicals, reducing the hair pigment.

In summary, as we age, our bodies produce less melanin, causing gray hair. However, some people notice gray hair earlier, in their 20s. As it turns out, genetics play one of the most important roles in the appearance of premature gray hair, however, stress, certain health conditions, and vitamin and mineral deficiencies can also increase the risk.