The article reviews the current state of adjuvants used in allergen-specific immunotherapy (AIT) and their potential to improve the treatment of type I allergies. Type I allergies, or allergies, are caused by Th2-mediated immune responses to environmental antigens. AIT is the only disease-modifying treatment that can potentially restore clinical tolerance to allergens, but it has limitations such as long treatment durations, the risk of allergic side effects, and the low immunogenicity of allergens. Adjuvants can enhance the immunogenicity of allergens and induce desired immune responses, such as promoting Th1- or regulatory responses. The review covers the currently approved adjuvants for human AIT, including aluminum hydroxide, calcium phosphate, microcrystalline tyrosine (MCT), and monophosphoryl lipid A (MPLA). These adjuvants have distinct properties, such as prolonging allergen release, inducing specific IgG production, and reducing IgE levels. The article also discusses novel adjuvants under investigation, such as oil-in-water emulsions, virus-like particles (VLPs), viral components, carbohydrate-based adjuvants (QS-21, glucans, and mannan), and TLR-ligands (flagellin and CpG-ODN). The review highlights the advantages and disadvantages of each adjuvant, emphasizing their potential to improve AIT by enhancing immune responses, reducing side effects, and promoting a balanced Th1/Th2 immune profile. The future of AIT may lie in better understanding the immunological mechanisms underlying the effects of these adjuvants to further enhance their therapeutic potential.The article reviews the current state of adjuvants used in allergen-specific immunotherapy (AIT) and their potential to improve the treatment of type I allergies. Type I allergies, or allergies, are caused by Th2-mediated immune responses to environmental antigens. AIT is the only disease-modifying treatment that can potentially restore clinical tolerance to allergens, but it has limitations such as long treatment durations, the risk of allergic side effects, and the low immunogenicity of allergens. Adjuvants can enhance the immunogenicity of allergens and induce desired immune responses, such as promoting Th1- or regulatory responses. The review covers the currently approved adjuvants for human AIT, including aluminum hydroxide, calcium phosphate, microcrystalline tyrosine (MCT), and monophosphoryl lipid A (MPLA). These adjuvants have distinct properties, such as prolonging allergen release, inducing specific IgG production, and reducing IgE levels. The article also discusses novel adjuvants under investigation, such as oil-in-water emulsions, virus-like particles (VLPs), viral components, carbohydrate-based adjuvants (QS-21, glucans, and mannan), and TLR-ligands (flagellin and CpG-ODN). The review highlights the advantages and disadvantages of each adjuvant, emphasizing their potential to improve AIT by enhancing immune responses, reducing side effects, and promoting a balanced Th1/Th2 immune profile. The future of AIT may lie in better understanding the immunological mechanisms underlying the effects of these adjuvants to further enhance their therapeutic potential.