Despite being a widely recognised phenomenon, PMS (Premenstrual Syndrome) remains difficult to clinically define, with no universally agreed diagnostic criteria (Halbreich, 2007; Knaapen & Weisz, 2008; 2009). This lack of standardisation has contributed to a history of nonreplicable and contradictory clinical research findings (Budeiri et al., 1994; Knaapen & Weisz, 2008). The biological causal mechanism(s) of PMS also remain elusive (RCOG, 2016). Crucially, by virtue of being associated with menstruation, PMS also exists as a highly gendered and stigmatised cultural label (Johnston-Robledo & Chrisler, 2013; Ussher, 2005). Thus, critical scholars have argued that PMS is a socially constructed diagnosis that reflects the medicalisation of the female reproductive body- a process by which healthy experiences are positioned as pathological and used to justify discriminatory beliefs and practices (Caplan, 1995; Chrisler & Gorman, 2015; Martin, 1987; Ussher, 2005). Preliminary research found that the symptoms most frequently and prominently cited in both the biomedical and critical PMS literatures were mood-based (King, 2020). Given that population studies suggest that these are not the most common, uniquely determining, nor most disruptive symptoms (e.g., Dennerstein et al., 2011; Mallia, 2015; Romans et al., 2012), the rationale for prioritising them over physical ones was unclear. The main aim of this study was, therefore, to help better define and distinguish non-pathological physiological changes from debilitating premenstrual symptoms by integrating and comparing biomedical, critical, and patient accounts of PMS, with robust epidemiological data. The rationale being that if not based on empirical data, descriptions of PMS must be influenced by other discursive, embodied, material, or institutional factors. A mixed methods Critical Realist Discourse Analysis (CRDA) approach was used to examine the ways in which twelve self-defined 'PMS sufferers' (patients) and sixteen of the world's top biomedical and critical PMS experts described PMS. Their descriptions reproduced three gender myths ('femininity as debility', 'all in her mind', and 'the mysterious female body') more than they reflected the available empirical data. A major discursive omission was also identified in the participant accounts; the reduction of menstrual physiology to 'hormonal changes', only. It, thus, appears that the metaphorical pairing of 'women' and 'hormones' has restricted scientific and societal knowledge regarding menstrual physiology, resulting in the unintentional reproduction of gender myths. It is argued that a more empirically robust redefinition of premenstrual symptoms as indicative of PMI (Perimenstrual Inflammation) could improve patient outcomes, reduce stigma, and help account for female-prevalent symptoms without unintentionally stigmatising an entire gender.