Premature hair graying (PHG) is one of the most prevalent conditions affecting individuals worldwide. It has been recognized as an important cause of low self-esteem, with a significant physical and social impact. This study investigated the factors associated with PHG by comparing medical students and resident physicians to other non-medical majors at Imam Abdulrahman Bin Faisal University (IAU). This is a comparative cross-sectional study conducted on resident physicians and students from 10 different colleges of IAU, Eastern Province, Saudi Arabia. This study evaluated the characteristics of PHG and its associated risk factors using an online distributed questionnaire. A total of 2644 students and resident physicians were included in this study, with 45.6% coming from medical colleges. The findings show that the premature graying of hair was higher among obese and overweight individuals and those with a combined deficiency of vitamins B12 and vitamin D. Other factors associated with PHG included a family history of PHG, a lack of exercise, smoking, and allergic rhinitis. Gray hair onset before 25 years old was higher among those with high stress levels (95%) than those with moderate (90%) and or mild (86%) stress levels ( = 0.029). In our study, higher stress levels were related to an earlier age of PHG onset, and there was no difference between medical and non-medical students in PHG. Recommendations for future research include randomized clinical trials and larger cohort studies regarding the characteristics of PHG in the Middle East and those with Arabic ethnicity and assessing the medications that induce possible hair repigmentation.