Introduction: Hairdressers, barbers, and related workers are chronically exposed to complex mixtures used in hair coloring, including oxidative permanent dyes containing aromatic amines (p-phenylenediamine and related intermediates), bleaching agents (persulfates, hydrogen peroxide), and associated solvents and aerosols. Several of these substances have raised toxicological and epidemiological concern. The cancer sites most frequently investigated in this context include urinary bladder, hematological malignancies (non-Hodgkin lymphoma, leukemia), and lung cancer, although evidence remains heterogeneous across studies and periods of exposure.
 
Objective: The aim of the study is to systematically appraise and synthesize evidence from published systematic reviews and meta-analyses on occupational exposure to hair coloring products and risk of site-specific cancers, and to assess the credibility of reported associations for carcinogenic hazard evaluation.
 
Methods: An umbrella review is conducted in accordance with PRISMA 2020 guidance for overviews of reviews. MEDLINE, Embase, Web of Science, and the Cochrane Library are searched from inception to March 2026 for systematic reviews and meta-analyses of epidemiological studies evaluating cancer incidence or mortality among hairdressers, barbers, beauticians, or workers with occupational hair dye exposure. Study selection, data extraction, and methodological quality assessment are performed independently by two reviewers. For each cancer site, pooled effect estimates, between-study heterogeneity, small-study effects, and overlap of primary studies (corrected covered area) are summarized. Certainty of evidence is graded using a tailored approach emphasizing exposure specificity, control of major confounders, and stratification by historical periods of dye formulation. Results are considered preliminary.
 
Results: The preliminary search has identified approximately 12–16 systematic reviews/meta-analyses, encompassing more than 100 epidemiological studies (predominantly case–control and record-linkage cohort designs). Bladder cancer is the most consistently evaluated outcome, with several meta-analyses reporting modestly elevated relative risks in hairdressers, particularly in studies including employment prior to regulatory changes in dye composition. Evidence for hematological malignancies is inconsistent, with heterogeneous estimates across subtypes. For lung cancer, pooled analyses suggest small excess risks that attenuate after adjustment for smoking and other occupational co-exposures. Across cancer sites, heterogeneity is substantial, and exposure misclassification and residual confounding remain frequent methodological limitations.
 
Conclusions: Our preliminary review provides a structured assessment of the epidemiological synthesis, potentially linking occupational exposure to hair coloring products with cancer risk. Although observed associations are generally modest and heterogeneous, the findings support the need for preventive action in these work environments. Public health interventions should include: substitution with less hazardous formulations; improved product labeling and transparency regarding aromatic amines and other sensitizing or potentially carcinogenic components; enforcement of ventilation standards, glove use, and dermal and inhalation exposure controls; and targeted occupational health surveillance for long-term workers. Engagement of regulators, manufacturers, professional associations, and employers is essential to translate evidence into effective risk reduction for this large workforce.