Background: The widespread use of cosmetic products, particularly skin-lightening preparations, in Nigeria has raised significant public health concerns due to adverse cosmetic events (ACE) linked to inadequate labelling, misleading advertising, and weak regulatory enforcement by the National Agency for Food and Drug Administration and Control (NAFDAC).

Objective: This study assessed access to accurate cosmetic information and its impact on the prevalence of ACE in Abuja, Nigeria.

Methods: A cross-sectional mixed-methods study was conducted among 434 cosmetic consumers in the Federal Capital Territory (FCT). Data were collected using structured questionnaires and analysed using descriptive statistics and chi-square tests. Additionally, 12 Key Informant Interviews (KIIs) were conducted with regulators, manufacturers, retailers, and healthcare providers, and analysed using thematic analysis. A compliance assessment was conducted on 60 cosmetic products across five categories.

Results: Consumer trust in cosmetic labelling was low, with only 37.7% agreeing that ingredient lists are accurate and 37.9% trusting advertising claims. Although 47.8% reported understanding product labels, 79.5% were unable to identify harmful ingredients. The prevalence of ACE was high at 69.6% and was significantly associated with sex (p < 0.001), marital status (p = 0.032), religion (p< 0.001), employment status (p = 0.035), and income (p < 0.001). Compliance assessment revealed wide variation across product categories: oral care products demonstrated high compliance (91.7%), skin and hair care were moderately compliant (70.8% each), nail care showed low compliance (54.2%), and fragrances/perfumes demonstrated very poor compliance (33.3%). Qualitative findings revealed persistent labelling gaps, exaggerated marketing claims, informal market repackaging practices, and enforcement limitations.

Conclusion: Inadequate labelling, deceptive advertising, and regulatory weaknesses significantly contribute to the high prevalence of ACE, underscoring the need for strengthened enforcement and improved consumer education. Future longitudinal and product- specific studies are recommended to inform sustained policy interventions.