In recent years, innovative and well-researched smart devices utilizing wearable biosensor systems for health monitoring have attracted much attention from society. These health monitoring devices, equipped with various transmission modules and miniature physiological sensors, are anticipated to alleviate the escalating healthcare expenses in the post-pandemic era by offering real-time, precise physiological information and persistent health status monitoring. Additionally, such health monitoring devices can provide tailored health advice and preventive measures for healthcare providers, potentially transforming the future of healthcare. Hence, their impact spans a broad and enduring spectrum in our daily lives. This paper aims to provide a comprehensive review of current technologies used for health monitoring and current trends, developments, and research in wearable biosensor systems for health monitoring. The focus is especially on the technical design of multiparameter physiological sensing systems and the challenges they face. Also, it discusses the ethical and data protection issues associated with these wearable biosensor systems. Finally, future research directions and perspectives on wearable biosensor devices are analyzed. Moreover, this paper serves as a resource for researchers and developers in this field, providing directions for future research advancements.