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Prediabetes Numbers: What Your A1C and Fasting Glucose Mean
Prediabetes means an A1C of 5.7% to 6.4%, a fasting glucose of 100 to 125 mg/dL, or a 2-hour glucose test of 140 to 199 mg/dL (NIDDK, Diabetes & Prediabetes Tests). Diabetes starts at 6.5%, 126 mg/dL or 200 mg/dL. The CDC counts 115.2 million U.S. adults with prediabetes (CDC, National Diabetes Statistics Report). Lifestyle change has the strongest proof of lowering risk.
Written by the Olivaro editorial teamUpdated · 9 min read
The cutoffs
What numbers mean prediabetes?
Prediabetes means blood sugar above normal but not yet in the diabetes range. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sets the cutoffs by test (NIDDK, Diabetes & Prediabetes Tests).
Three tests are used. An A1C test, a fasting plasma glucose test, and a 2-hour oral glucose tolerance test (OGTT). Any one of them can point to prediabetes. A clinician then decides what the result means for you.
One high result is a signal, not a final answer. NIDDK notes that a diabetes diagnosis needs confirmation (NIDDK, Diabetes & Prediabetes Tests). Labs vary, and so do people from day to day. Our blood sugar basics guide explains how glucose and insulin work together.
At a glance
What are the normal, prediabetes and diabetes ranges?
Normal is an A1C below 5.7% and a fasting glucose of 99 mg/dL or below. Prediabetes and diabetes start at the cutoffs below.
- NormalA1CBelow 5.7%Fasting glucose99 mg/dL or below
- PrediabetesA1C5.7% to 6.4%Fasting glucose100 to 125 mg/dL
- DiabetesA1C6.5% or higherFasting glucose126 mg/dL or higher
NIDDK ranges (NIDDK, Diabetes & Prediabetes Tests). Only a lab test and a clinician can make a diagnosis. Low blood sugar usually means a reading below 70 mg/dL (NIDDK, Low Blood Glucose).
| Test | Prediabetes | Diabetes |
|---|---|---|
| A1C | 5.7% to 6.4% | 6.5% or higher |
| Fasting plasma glucose | 100 to 125 mg/dL | 126 mg/dL or higher |
| 2-hour OGTT | 140 to 199 mg/dL | 200 mg/dL or higher |
A home meter reading is useful for tracking. It is not the same as a lab test, and it does not diagnose prediabetes.
The tests
What is the difference between A1C and fasting glucose?
A1C reflects your average blood sugar over the past few months. Fasting glucose is a snapshot of one morning after you have not eaten overnight. Both have a place.
- A1C: a percent. No fasting needed. Good for the big picture.
- Fasting glucose: mg/dL. Shows where you start the day.
- OGTT: mg/dL two hours after a sweet drink. Shows how your body handles a sugar load.
Results can disagree. You might have an A1C in the normal range and a fasting number in the prediabetes range, or the other way around. That is a good reason to ask which test your doctor used and when to repeat it. Bring past results to each visit so the trend is easy to see.
CDC data
How many Americans have prediabetes?
About 115.2 million U.S. adults have prediabetes, according to the CDC's 2026 report using 2023 data (CDC, National Diabetes Statistics Report).
The same report counts 40.1 million people with diabetes, or 12.0% of the population. About 11 million adults with diabetes have not been diagnosed (CDC, National Diabetes Statistics Report). Many people simply have not been tested.
Prediabetes often goes unnoticed, which is why a simple blood test matters more than waiting for signs. Once blood sugar climbs into the diabetes range, symptoms are more likely.
The CDC lists frequent urination, more thirst and hunger, weight loss you did not try for, tiredness, blurry vision and frequent infections. Type 2 diabetes can also bring slow-healing sores and numbness or tingling in the hands or feet (CDC, Symptoms of Diabetes). Tell your doctor if you notice any of these.
The DPP in numbers
What lowered risk in the Diabetes Prevention Program?
Figures from NIDDK's summary of the Diabetes Prevention Program (NIDDK, Diabetes Prevention Program).
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How did lifestyle change compare with metformin?
Lifestyle change did better. In the DPP, people who aimed for 7% weight loss and 150 minutes of exercise a week cut their risk of type 2 diabetes by 58% versus placebo. Metformin cut it by 31% (NIDDK, Diabetes Prevention Program).
| Group | What they did | Risk reduction |
|---|---|---|
| Lifestyle change | 7% weight loss goal, 150 minutes of activity a week | 58% |
| Lifestyle change, age 60+ | Same program | 71% |
| Metformin | Prescription medicine | 31% |
| Any dietary supplement | Not tested in the DPP | No data |
The CDC puts the goal in plain terms. Losing 5% to 7% of your weight, about 10 to 14 pounds for a 200-pound person, plus 150 minutes a week of brisk activity, can help prevent type 2 diabetes (CDC, Prediabetes).
What to do
What should you do after a prediabetes result?
Ask your doctor to confirm the result and set a plan. Then start with the changes that have the best record.
Confirm and record
Write down the test type, the number and the date. Ask when to repeat it.
Ask about a lifestyle program
The CDC-led National Diabetes Prevention Program can lower risk by 58%, and by 71% for people over 60 (CDC, Prediabetes).
Move a little most days
Work up to 150 minutes a week. Brisk walks count.
Aim for a modest weight change
A 5% to 7% loss is the target, not a dramatic diet.
Recheck on schedule
Compare your next A1C or fasting number with the first one. Use the same type of test each time so the comparison is fair.
Supplements
Can a supplement like Olivaro help with prediabetes?
No supplement has been shown to treat prediabetes or diabetes. NCCIH finds little evidence for most supplements and warns against replacing medical care with one (NCCIH, Diabetes and Dietary Supplements).
Olivaro's sales page positions it as "nutritional support for glucose metabolism, metabolic health, and weight management." It is a dietary supplement, not a diabetes medicine. No study of Olivaro has been published. Our claims vs evidence page sets each claim next to the research.
If you try any supplement, add it on top of lifestyle change, never in place of it. Keep testing on the same schedule so you can see what really moves your numbers. Never change a diabetes medicine without talking to your doctor first. Our results timeline shows how to plan a fair 30- and 60-day check.
We are the U.S. stocking partner for Olivaro and earn money on orders. We would still point you to the DPP steps first.
FAQ
Prediabetes number questions
What A1C level is prediabetes?
An A1C of 5.7% to 6.4% is in the prediabetes range, according to NIDDK (NIDDK, Diabetes & Prediabetes Tests). Below 5.7% is normal, and 6.5% or higher is in the diabetes range. A diagnosis of diabetes needs a confirming test, so ask your doctor when to repeat it.
What fasting blood sugar is prediabetes?
A fasting plasma glucose of 100 to 125 mg/dL is in the prediabetes range (NIDDK, Diabetes & Prediabetes Tests). A reading of 99 mg/dL or below is normal, and 126 mg/dL or higher points to diabetes. Lab tests are more reliable for diagnosis than home meter readings.
Is an A1C of 5.7 bad?
An A1C of 5.7% is the start of the prediabetes range (NIDDK, Diabetes & Prediabetes Tests). It is a warning sign, not a disaster. The DPP showed that modest weight loss and 150 minutes of weekly activity cut the risk of type 2 diabetes by 58% (NIDDK, Diabetes Prevention Program).
Can prediabetes go back to normal?
Many people can lower their risk a lot. In the DPP, lifestyle change aiming for 7% weight loss and 150 minutes of activity a week cut type 2 diabetes risk by 58% (NIDDK, Diabetes Prevention Program). Your doctor can recheck your numbers and tell you where you stand.
How many people have prediabetes in the U.S.?
The CDC estimates 115.2 million U.S. adults have prediabetes, using 2023 data (CDC, National Diabetes Statistics Report). The same report counts 40.1 million people with diabetes, 12.0% of the population, including about 11 million adults who have not been diagnosed.
What is a normal fasting blood sugar level?
A normal fasting plasma glucose is 99 mg/dL or below, based on the NIDDK cutoffs (NIDDK, Diabetes & Prediabetes Tests). From 100 to 125 mg/dL is prediabetes. For people who take diabetes medicine, a reading below 70 mg/dL is generally considered low and needs quick action (NIDDK, Low Blood Glucose).
Does Olivaro lower A1C?
No study shows that Olivaro lowers A1C, and no trial of the product has been published. It is a dietary supplement, not a diabetes medicine. Its sales page positions it for nutritional support of glucose metabolism. Lifestyle change has the strongest evidence for lowering diabetes risk.
How often should I check my A1C with prediabetes?
Ask your doctor, because the right schedule depends on your numbers and health. Ask whether to repeat the same test so the numbers compare fairly. Write down each result with its date so you and your doctor can see the trend.
Who wrote this
Written and reviewed by
Plain-language pages built from the label, the sales page and linked public health sources.
Page updated . See our editorial standards and how we check reviews. This website is run by a U.S. stocking partner, not by the manufacturer. Purchases through our order links earn us money.
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