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Understanding Your A1C: What GLP-1 Patients Need to Know
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Weight loss
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Why Some Patients and Providers Monitor A1C
It is important to understand that labs are not required to receive GLP-1 medications for weight management. Many patients successfully use these medications without any lab testing. However, some patients and providers find A1C monitoring helpful for specific reasons.
Establishing Baseline for Future Reference
Checking A1C within the first month of starting GLP-1 therapy provides a baseline measurement at the time treatment begins. If you do not currently have insurance coverage for your medication and may need to pursue prior authorization in the future, having a baseline A1C measurement, demonstrating A1C reduction with treatment, and showing maintenance of improved A1C with continued treatment can strengthen prior authorization requests. Insurance companies sometimes require evidence that medication is providing medical benefit beyond just weight loss.
Assessing Metabolic Improvement Beyond Weight
Weight loss is not always linear. You might have weeks where the scale does not move or even goes up slightly despite adherence to treatment. During these plateaus, it can be frustrating when you are not seeing progress on the scale. A1C provides another way to assess whether medication is delivering metabolic benefits. If your A1C has improved significantly even during a weight plateau, this indicates the treatment is working to improve your metabolic health.
For people with prediabetes, watching A1C trend downward toward normal range provides motivation and confirms that you are reducing your diabetes risk. For people with diabetes, seeing A1C improve demonstrates better disease control that reduces risk of long-term complications.
Monitoring for Diabetes Risk
If you have risk factors for diabetes (family history, previous gestational diabetes, PCOS, or other conditions associated with insulin resistance), periodic A1C checking helps catch progression toward diabetes early. While GLP-1 medications generally improve blood sugar control, monitoring confirms this is happening for you individually.
The decision about whether to check A1C should be made collaboratively between you and your provider based on your individual health goals, medical history, and whether the information would be helpful for your care. There is no requirement to check labs, and the choice should be based on shared decision-making about what monitoring makes sense for your situation.
Interpreting Your A1C Results on GLP-1 Therapy
If you and your provider decide to check A1C, understanding what your results mean helps you assess your metabolic health.
If Your A1C Is in the Normal Range (Below 5.7%)
This indicates excellent blood sugar control. If you started treatment with prediabetes or diabetes and your A1C has improved to the normal range, this represents significant metabolic improvement. If you started with normal A1C, maintaining it while losing weight confirms that your blood sugar regulation remains healthy.
If Your A1C Is in the Prediabetes Range (5.7% to 6.4%)
This indicates elevated blood sugar that has not yet reached diabetes levels. If you started with prediabetes and your A1C has decreased within this range (for example, from 6.2% to 5.9%), this represents improvement and reduced diabetes risk even though you are still technically in the prediabetes category.
The goal with prediabetes is generally to move toward the normal range (below 5.7%) or at minimum to prevent progression toward diabetes (6.5% or higher). Most people taking GLP-1 medications with prediabetes at baseline see their A1C improve, often into the normal range, though individual results vary.
If Your A1C Is in the Diabetes Range (6.5% or Higher)
If you have diabetes and started treatment with elevated A1C, the question is whether your A1C is improving with treatment. Most people with diabetes taking GLP-1 medications see meaningful A1C reductions. In clinical trials, average reductions ranged from 1.5 to 2.0 percentage points or more depending on baseline levels and which GLP-1 medication is used.
If your A1C is not improving despite several months on GLP-1 therapy, discuss this with your provider. Possible explanations include needing a higher dose, requiring additional diabetes medications, or needing to reassess lifestyle factors affecting blood sugar.
When to Check A1C and How Often
If you and your provider decide that A1C monitoring would be helpful for your care, the frequency depends on your individual situation and goals.
For people without diabetes or prediabetes who are taking GLP-1 medications purely for weight management, A1C checking is optional. Some patients and providers choose to check it once at baseline and perhaps once or twice during the first year of treatment to confirm metabolic health is stable or improving. Others do not check it at all if there are no concerns about blood sugar regulation.
For people with prediabetes at baseline, checking A1C every six to 12 months while on treatment helps monitor whether blood sugar is normalizing or whether progression toward diabetes is occurring. More frequent checking is generally not needed since A1C reflects a three-month average, so checking more often than every three months provides limited additional information.
For people with type 2 diabetes taking GLP-1 medications, the American Diabetes Association recommends A1C testing at least twice yearly if you are meeting treatment goals with stable control. If your diabetes treatment has changed recently or you are not meeting glycemic targets, testing every three months makes sense until control improves and stabilizes.
The specific monitoring plan should be determined collaboratively with your provider based on your health status and goals. There is no single right answer that applies to everyone.
What to Do If Your A1C Shows Concerning Patterns
If A1C testing reveals unexpected or concerning results, several steps help you respond appropriately.
If A1C Is Rising Despite Treatment
If your A1C increases or fails to improve despite several months on GLP-1 therapy and lifestyle modifications, discuss this with your provider. They may recommend increasing your GLP-1 dose if you are not yet at the maximum, evaluating your diet and physical activity patterns, checking for other conditions affecting blood sugar, or considering whether additional medications might be needed.
For people with diabetes, rising A1C might indicate that GLP-1 therapy alone is insufficient for optimal control and combination therapy might be beneficial.
If A1C Indicates New Diabetes Diagnosis
If you did not previously have diabetes but testing reveals an A1C of 6.5% or higher, this generally requires confirmation with repeat testing on a different day. If confirmed, this represents a new diabetes diagnosis that requires discussion with your provider about treatment modifications, monitoring frequency, and potential need for additional therapies beyond GLP-1 medication.
If A1C Indicates Progression From Prediabetes
If you had prediabetes and your A1C has increased to 6.5% or higher, this indicates progression to diabetes. Your provider should discuss whether your current treatment plan needs adjustment, what additional interventions might help, and how to prevent further progression.
The Bigger Picture: A1C as One Measure of Health
While A1C is valuable for assessing blood sugar control and diabetes risk, it represents only one aspect of your health. Comprehensive assessment includes body weight and body composition, blood pressure, lipid panel (cholesterol and triglycerides), liver and kidney function, and overall quality of life and physical function.
GLP-1 medications typically improve many of these markers simultaneously. Weight loss reduces blood pressure. Metabolic improvements affect cholesterol levels. Reduced inflammation benefits multiple organ systems. A1C is one measure of this broader metabolic improvement, not the only measure that matters.
At Mochi Health, we understand that every person's health journey is unique. Our providers offer personalized treatment plans that consider your complete health picture, not just single numbers. Beyond GLP-1 medications for weight management, we offer comprehensive care including registered dietitian nutritionists, support for related health conditions, and access to a wide range of medications that can support your overall health. You can explore treatment options at https://joinmochi.com/medications.
If you and your provider decide that A1C monitoring would be helpful for your care, this is a choice you make together based on your individual circumstances and goals. Labs are never required for GLP-1 treatment, but they can provide valuable information when monitoring makes sense for your situation.
Check Your Eligibility
If you want to learn whether GLP-1 treatment is right for you and receive personalized guidance from providers who understand comprehensive metabolic health assessment including appropriate use of A1C monitoring, you can start by completing Mochi's eligibility questionnaire. Check your eligibility.
References:
American Diabetes Association. (2023). Standards of medical care in diabetes—2023. Diabetes Care, 46(Supplement 1), S19-S40. https://doi.org/10.2337/dc23-S002
Centers for Disease Control and Prevention. (2025). A1C test for diabetes and prediabetes. U.S. Department of Health and Human Services. https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html
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National Institute of Diabetes and Digestive and Kidney Diseases. (2025). The A1C test & diabetes. U.S. Department of Health and Human Services. https://www.niddk.nih.gov/health-information/diagnostic-tests/a1c-test
Perreault, L., Davies, M., Frias, J. P., Laursen, P. N., Lingvay, I., Machineni, S., Varbo, A., Wilding, J. P. H., Wallenstein, S. O. R., & le Roux, C. W. (2023). Changes in glucose metabolism and glycemic status with once-weekly subcutaneous semaglutide 2.4 mg among participants with prediabetes in the STEP program. Diabetes Care, 46(12), 2252-2262. https://doi.org/10.2337/dc23-0556
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This article is for educational purposes only and should not be considered medical advice. Consult with healthcare providers about whether A1C testing is appropriate for your individual health needs and circumstances.
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