The use of in-body wearable devices is increasing in the healthcare sector, given their capacity to diagnose diseases and monitor health conditions. At the same time, some of these devices have entered the market and are being researched for use in workplace settings to enhance workers’ health and safety. However, neither specific EU legislation nor national law currently regulates the use of in-body wearables in employment, raising questions about the safeguarding of workers’ fundamental rights to privacy and data protection. Addressing the challenges posed by this regulatory gap, this article explores whether the European legislative framework employed in the healthcare sector for medical devices could be applied to the use of in-body wearables in employment settings. It also discusses the application of a key principle of the General Data Protection Regulation when in-body wearables are used in the workplace: lawfulness.