The exponential and indiscriminate use of dietary supplements and weight loss compounds has become a significant public health problem, drawing attention from national and international regulatory agencies. The objective of this study is to provide evidence of how the quality of synephrine varies over time under the influence of UV light. Photodegradation kinetic studies were conducted under UV light to assess the degradation of synephrine. In silico and LC-ESI-MS studies were utilized to identify the major degradation product of synephrine. Additionally, a biological safety study was conducted to evaluate the effects of the photodegraded synephrine in comparison to the intact molecule. In the photodegradation kinetic studies, the drugs exhibited a second-order reaction rate under the specific experimental conditions applied. Key kinetic parameters such as rate constant, half-life (t1/2), and the time at which 90% of the original drug concentration remained were determined. Based on the in silico studies and confirmation of molecular weight, a comprehensive degradation pathway of the drug and the identification of its major degradation product could be suggested without the need for purification processes or complex isolation techniques. The results revealed the higher reactivity of the side chain amino group, indicating the formation of chroman amino. Additionally, the biological safety study demonstrated that the degraded sample had an impact on cell viability and exhibited genotoxic potential. The quality of synephrine changes over time under the influence of light. These findings emphasize the importance of exercising caution during the handling, manufacturing, and storage of pharmaceutical preparations or food supplements containing synephrine.