HbA1c

HbA1c (Glycated Hemoglobin)

HbA1c, also known as glycated hemoglobin or glycosylated hemoglobin, is formed when glucose in the blood attaches to hemoglobin in red blood cells. Because red blood cells have a lifespan of approximately 120 days, the HbA1c measurement provides an integrated picture of average blood glucose control over the preceding two to three months. This makes HbA1c far more informative than a single fasting glucose reading, which captures only a momentary snapshot.

HbA1c is expressed as a percentage of total hemoglobin. In people without diabetes, HbA1c typically ranges from 4.0% to 5.6%. A value of 5.7-6.4% indicates prediabetes, while 6.5% or higher is diagnostic of diabetes. For most adults with type 2 diabetes, treatment guidelines recommend targeting an HbA1c below 7.0%, though individual targets may vary based on patient characteristics and risk of hypoglycemia.

In the Phase 2 retatrutide trial in type 2 diabetes (NCT04867785, published in The Lancet), participants had a mean baseline HbA1c of approximately 8.3%. Treatment with retatrutide produced dose-dependent reductions in HbA1c, with the highest dose groups achieving mean reductions of approximately 2.0 percentage points, bringing the average well below the 7.0% treatment target. A substantial proportion of participants achieved HbA1c levels below 5.7%, which is considered the normal, non-diabetic range. These results demonstrated retatrutide’s potent glucose-lowering effects, driven by the combined actions of its GIP, GLP-1, and glucagon receptor agonism.