More than 1.8 billion people menstruate every month. Yet menstruation is still a taboo, including in the workplace, where the multiple challenges of menstruating workers remain largely unaddressed from exclusion from certain branches to inadequate facilities, inflexible workloads, and period jokes. To address this issue, the Swedish organisation MENSEN has developed Period Works!, a unique ‘menstrual certification' involving employers, employees, and trade unions ‘to create a more period friendly work life'. The initiative reveals menstruators' challenges at work, particularly in terms of their rights to health, privacy, non-discrimination, and collective bargaining. Yet so far the legal literature and policies on the issue are scarce. To fill this gap, inspired by Period Works!, this article conceptualises a comprehensive human rights framework to promote menstrual health at work. It analyses whether states and employers, who mostly ignore menstruators' needs, are in breach of their existing legal obligations to promote menstruating workers' rights. The article also critically examines whether recognising menstruators’ rights at work would truly be a blessing, or if menstrual mainstreaming at work could increase discrimination and be a curse. The article argues that only a carefully crafted comprehensive human rights framework for menstrual health at work can address this paradox.