Contemporary public debate has discussed young women's deteriorating mental health and linked this development to the negative effects of social media. Simultaneously, digital media apps like TikTok have become platforms where new types of therapeutic content have emerged, and young people increasingly discuss mental health in their multimodal media practices. On TikTok, music is central in these processes as TikTok users utilize platform features that enable them to record, save, and repurpose sound and music. While music has been used as a therapeutic tool and as an art form that fosters negotiations of feelings, its use in mediations of mental health in digital media culture has not yet been studied. Against this backdrop, this project contributes a highly relevant examination of young women's negotiations of mental health through musical participation on TikTok. The project answers three research questions: 1) How do young women negotiate mental health, emotions, and gendered subjectivity through musical participation? 2) How are users' negotiations shaped by sonic and musical qualities as well as TikTok's sociotechnical and algorithmic properties? 3) How can emergent gendered subjectivities at the intersection of music, technology, and affect be theorized? The project combines methods for (online) ethnography, auditory analysis, and multimodal discourse analysis with theoretical perspectives from feminist sound and science and technology studies as well as affect theory.