Background: Acne vulgaris is a common inflammatory skin condition affecting adolescents and young adults, with significant physical and psychological impacts. Emerging evidence suggests that nutritional deficiencies may influence its development and severity, yet the relationship remains underexplored.Objective: To investigate the association between nutritional deficiencies and the severity of acne vulgaris in adolescents and young adults, focusing on key nutrients such as zinc, vitamin A, vitamin D, and omega-3 fatty acids.Methods: A cross-sectional study was conducted with 110 participants aged 13–25 years, categorized into mild, moderate, and severe acne groups based on the Global Acne Grading System (GAGS). Nutritional status was assessed through dietary surveys and serum measurements of zinc, vitamin A, vitamin D, and omega-3 fatty acids. Statistical analyses included correlation and multivariate regression to identify associations between nutrient levels, dietary patterns, and acne severity.Results: Participants with severe acne had significantly lower serum levels of zinc (57.6 ± 7.8 µg/dL), vitamin A (33.1 ± 4.9 µg/dL), vitamin D (14.6 ± 3.9 ng/mL), and omega-3 fatty acids (2.4 ± 0.7 mg/dL) compared to those with mild acne. High-glycemic index food consumption was more frequent among participants with severe acne (89% vs. 55% in mild acne). Significant inverse correlations were observed between nutrient levels and acne severity (e.g., zinc: r = -0.56, P < 0.01; vitamin D: r = -0.62, P < 0.01).Conclusion: Nutritional deficiencies, particularly in zinc, vitamin A, vitamin D, and omega-3 fatty acids, are strongly associated with increased acne severity. Dietary patterns high in high-glycemic index foods further exacerbate acne. Addressing these deficiencies through dietary modifications and supplementation may serve as an effective adjunct to conventional acne treatments.