Type 1 diabetes is an autoimmune disease causing insulin deficiency and loss of pancreatic β-cell function, requiring lifelong insulin therapy. Since insulin's discovery over 100 years ago, significant advances in treatment have improved care for people with type 1 diabetes. Research on genetics, immunology, and interventions has expanded understanding of the disease. Biomarkers detect type 1 diabetes months to years before symptoms, and three stages of diabetes are now recognized. Continuous glucose monitoring (CGM) and automated insulin delivery systems have transformed management, improving glycated hemoglobin (HbA1c) and reducing hypoglycemia. Adjunctive therapies like sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists may be useful in the future. Despite advances, people in under-resourced areas struggle to access essentials like insulin and glucose monitoring. Type 1 diabetes incidence is rising globally, with 8.7 million people affected in 2020, expected to rise to over 17 million by 2040. Diagnosis is often straightforward in children, but adult-onset type 1 diabetes is more common in Europe and less in Asia. Autoantibodies are key in diagnosis, and new methods like genetic risk scoring help identify at-risk individuals. Obesity has increased in people with type 1 diabetes, complicating management. CGM has improved glycemic control and reduced hypoglycemia compared to traditional blood glucose monitoring. Automated insulin delivery systems, including closed-loop or artificial pancreas systems, have shown benefits in glycemic control and quality of life. However, access is limited in low-resource settings. Newer CGM devices, like Sensionics, offer longer wear times and improved accuracy. Insulin analogs have evolved, with ultra-rapid acting insulins like lispro-aabc showing improved glycemic control. Pulmonary inhaled insulin is the fastest-acting, but its use is limited. Insulin delivery systems, including pumps and automated systems, have improved management but require training and support. β-cell replacement therapies, such as pancreas and islet transplantation, offer potential for insulin independence but are limited by donor availability and immunosuppression. Disease-modifying treatments like teplizumab delay progression in early type 1 diabetes but are not yet widely available. Adjunctive therapies like metformin and GLP-1 agonists may help with glycemic control and weight management but are not recommended for type 1 diabetes. SGLT-2 inhibitors show promise but carry risks of diabetic ketoacidosis. Diabetic ketoacidosis (DKA) is a serious complication, with rising rates in adults. Management includes insulin infusion and fluid resuscitation. Hypoglycemia is common and can lead to severe consequences, requiring careful monitoring and treatment. In under-resourced settings, access to insulin,Type 1 diabetes is an autoimmune disease causing insulin deficiency and loss of pancreatic β-cell function, requiring lifelong insulin therapy. Since insulin's discovery over 100 years ago, significant advances in treatment have improved care for people with type 1 diabetes. Research on genetics, immunology, and interventions has expanded understanding of the disease. Biomarkers detect type 1 diabetes months to years before symptoms, and three stages of diabetes are now recognized. Continuous glucose monitoring (CGM) and automated insulin delivery systems have transformed management, improving glycated hemoglobin (HbA1c) and reducing hypoglycemia. Adjunctive therapies like sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists may be useful in the future. Despite advances, people in under-resourced areas struggle to access essentials like insulin and glucose monitoring. Type 1 diabetes incidence is rising globally, with 8.7 million people affected in 2020, expected to rise to over 17 million by 2040. Diagnosis is often straightforward in children, but adult-onset type 1 diabetes is more common in Europe and less in Asia. Autoantibodies are key in diagnosis, and new methods like genetic risk scoring help identify at-risk individuals. Obesity has increased in people with type 1 diabetes, complicating management. CGM has improved glycemic control and reduced hypoglycemia compared to traditional blood glucose monitoring. Automated insulin delivery systems, including closed-loop or artificial pancreas systems, have shown benefits in glycemic control and quality of life. However, access is limited in low-resource settings. Newer CGM devices, like Sensionics, offer longer wear times and improved accuracy. Insulin analogs have evolved, with ultra-rapid acting insulins like lispro-aabc showing improved glycemic control. Pulmonary inhaled insulin is the fastest-acting, but its use is limited. Insulin delivery systems, including pumps and automated systems, have improved management but require training and support. β-cell replacement therapies, such as pancreas and islet transplantation, offer potential for insulin independence but are limited by donor availability and immunosuppression. Disease-modifying treatments like teplizumab delay progression in early type 1 diabetes but are not yet widely available. Adjunctive therapies like metformin and GLP-1 agonists may help with glycemic control and weight management but are not recommended for type 1 diabetes. SGLT-2 inhibitors show promise but carry risks of diabetic ketoacidosis. Diabetic ketoacidosis (DKA) is a serious complication, with rising rates in adults. Management includes insulin infusion and fluid resuscitation. Hypoglycemia is common and can lead to severe consequences, requiring careful monitoring and treatment. In under-resourced settings, access to insulin,