Several psychological risk factors are associated with patient dissatisfaction with aesthetic procedures, such as body dysmorphic disorder (BDD), unmanaged mental health concerns or unrealistic expectations. Identifying these risks via preoperative screening may protect patients from adverse psychological outcomes and provide reputational or legal protection for practitioners. This study aimed to further develop and validate the Cosmetic Readiness Questionnaire (CRQ), a comprehensive psychological screening tool to assess patient suitability for surgical and non-surgical aesthetic procedures. The CRQ was validated across two studies in clinical contexts, examining structural and construct validity in a sample of 8031 individuals who completed the CRQ as part of routine clinical care. In a further sample (n = 574), criterion validity was explored through the relationship between the CRQ and dissatisfaction with past aesthetic treatments. Risk category cut-off scores were developed. Results supported the reliability and validity of a five-factor CRQ which measures Body Dysmorphia, Psychological Distress, Self-Criticism, Unrealistic Expectations and Lack of Openness. High scorers on the CRQ were 78% more likely to report dissatisfaction with a past cosmetic procedure than low scorers. The CRQ is a comprehensive and valid screening measure to identify patients who may require further psychological assessment or additional support prior to aesthetic treatment. Instructions are provided on how to implement the CRQ in clinical practice.