Background: The side effects of two related chemicals, ammonium thioglycolate (ATG) and thioglycolic acid (TGA) have been widely highlighted in the world of cosmetics. These thioglycolate compounds are considered essential ingredients in a new technique known as brow lamination. This technique is widely used nowadays, with the aim of changing the eyebrow shape. Aims: To our knowledge, this is the first study to address the possible side effects of brow lamination. Results: The hydrophilic characteristic of ATG and TGA reflects their transdermal absorption through the intracellular and transappendageal pathways. These compounds can affect the skin through allergic contact dermatitis (ACD), characterized by skin irritation, dryness, and erythema. Moreover, these thioglycolates can alter several mechanical and chemical reactions in the eyebrows' hair, therefore affecting their shape, structure, and pigmentation. In addition, these chemicals contained in brow lamination can exert systemic manifestations, at the level of the reproductive, ocular, respiratory, and endocrine systems. Conclusion: More studies should be elaborated to shed light on the possible side effects of this trend. Additionally, further regulations should be taken into consideration to ensure the concentration and the measures applied are convenient to minimize these side effects.

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment by enhancing antitumor immune responses; however, clinical outcomes remain highly variable across patients and tumor types. While tumor-intrinsic factors such as PD-L1 expression and tumor mutational burden provide some predictive value, they do not fully explain response heterogeneity. Increasing evidence highlights the critical role of host-related determinants in modulating ICI efficacy. This review provides a comprehensive overview of key host factors, including baseline immune competence, T-cell repertoire diversity, cytokine profiles, and peripheral biomarkers. It further examines the impact of germline genetics, HLA genotype, and epigenetic regulation on immune responses. The role of the gut microbiome and its metabolites is explored, alongside the impact of metabolic status, obesity, nutrition, and lifestyle behaviors. Additionally, the effects of co-medications and comorbidities are discussed. Integrating these host-related factors may improve patient stratification and support the development of personalized immunotherapy strategies.