An A1c of 5.7% sits right at the boundary between normal blood sugar and prediabetes. It’s the lowest value in the prediabetes range (5.7 to 6.4%), which means your blood sugar has been running slightly higher than ideal over the past few months. The good news: this is the earliest possible warning, and at this level, the progression toward type 2 diabetes is far from inevitable.
What the A1c Test Actually Measures
The A1c test measures how much glucose has attached to hemoglobin, the protein inside your red blood cells that carries oxygen. As blood sugar rises, more glucose sticks to hemoglobin and stays there for the entire life of the cell. Since red blood cells live about three months, the test captures your average blood sugar over that window rather than a single snapshot.
For a 5.7% result, you can estimate your average blood sugar using a simple formula: multiply the A1c by 28.7, then subtract 46.7. That puts a 5.7% at roughly 117 mg/dL as a three-month average. For comparison, a fasting blood sugar reading in the normal range is under 100 mg/dL.
Where 5.7% Falls on the Scale
The diagnostic categories, set by the American Diabetes Association, break down like this:
- Normal: below 5.7%
- Prediabetes: 5.7 to 6.4%
- Diabetes: 6.5% or above
At 5.7%, you’re at the very bottom of the prediabetes range. Risk within this range isn’t flat. The higher your A1c climbs toward 6.4%, the greater your likelihood of developing type 2 diabetes. Being at 5.7% means your risk is elevated compared to someone at 5.4%, but it’s significantly lower than someone sitting at 6.2%.
What Prediabetes Means in Practice
Prediabetes isn’t a disease in the way diabetes is. It’s a metabolic warning signal. Your body is starting to have trouble processing blood sugar efficiently, usually because cells are becoming less responsive to insulin (the hormone that moves glucose out of your blood and into your cells). At 5.7%, this process is in its early stages.
Not everyone with prediabetes develops type 2 diabetes. Data from the CDC’s Diabetes Prevention Program found that people who lost 5 to 7% of their body weight and exercised at least 150 minutes per week reduced their risk of developing type 2 diabetes by 58%. For people over 60, the reduction was even larger: 71%. These benefits persisted over time, with participants still showing a 27% lower incidence of diabetes after 15 years.
For someone weighing 200 pounds, 5 to 7% weight loss means losing 10 to 14 pounds. That’s a realistic, moderate goal, not a dramatic overhaul.
When the Number Might Be Off
A1c is a reliable test for most people, but certain conditions can push the result higher or lower than your actual blood sugar warrants. Iron deficiency anemia, which is common in women of reproductive age, tends to make A1c read artificially high. That means some people get a 5.7% result when their true average blood sugar is actually normal.
Conditions that shorten the lifespan of red blood cells, like sickle cell trait or other hemoglobin variants, can also throw off results. Kidney disease, recent significant blood loss, and late pregnancy all affect accuracy. If you have any of these conditions, your doctor may rely on alternative tests like fructosamine or a glucose tolerance test to get a clearer picture.
Lifestyle Changes That Lower A1c
At 5.7%, lifestyle changes are the first and most effective intervention. Medication is generally not recommended at this level. There’s broad agreement among medical organizations that improving diet and exercise should come first, and research has not shown that starting blood sugar medication before a formal diabetes diagnosis improves quality of life or long-term health outcomes.
The changes that move the needle most are straightforward. Regular physical activity (at least 150 minutes per week of moderate exercise like brisk walking) improves how well your cells respond to insulin. Reducing refined carbohydrates and added sugars helps keep blood sugar from spiking after meals. Even modest weight loss, if you’re carrying extra weight, has a measurable impact on A1c.
These aren’t temporary fixes. The long-term data from prevention programs show that sustained, moderate changes in diet and activity level continue to protect against diabetes for years. You don’t need to train for a marathon or follow an extreme diet. Consistency with small changes matters more than intensity.
How Often to Retest
After a 5.7% result, your doctor will typically want to recheck your A1c within six to twelve months to see if it’s holding steady, improving, or climbing. If you make lifestyle changes, a retest in six months gives you enough time to see results reflected in the number. If your A1c rises or you have additional risk factors like a strong family history of diabetes, testing every three months may make more sense.
Tracking the trend matters more than fixating on a single number. A 5.7% that drops to 5.4% after six months of dietary changes tells a very different story than a 5.7% that creeps up to 5.9%. The goal is to move back below that 5.7% threshold or at least keep it from rising further.