Prediabetes rarely feels like anything. That’s exactly why it matters: it’s the one stage where the numbers are already moving, but nothing about your body has forced you to notice yet.
Quick answer: Prediabetes means your blood sugar is higher than normal but not yet in the diabetes range. It’s diagnosed with any of three tests: A1C between 5.7% and 6.4%, fasting glucose between 100 and 125 mg/dL, or a 2-hour oral glucose tolerance test result between 140 and 199 mg/dL, per the American Diabetes Association’s 2026 Standards of Care. It usually causes no symptoms, which is why routine screening, not waiting to feel something, is how most people find out.
What prediabetes actually means
Prediabetes describes a stage where blood sugar regulation is already under strain, but hasn’t yet crossed into the diabetes range. It isn’t a separate disease from type 2 diabetes; it’s an earlier point on the same continuum, which is exactly why it matters. The body is showing measurable signs of insulin resistance or reduced insulin response well before symptoms would ever prompt someone to get tested.
The three ways it’s diagnosed
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| A1C | Below 5.7% | 5.7%–6.4% | 6.5% or higher |
| Fasting glucose | Below 100 mg/dL | 100–125 mg/dL | 126 mg/dL or higher |
| 2-hour OGTT | Below 140 mg/dL | 140–199 mg/dL | 200 mg/dL or higher |
Why the three tests don’t always agree
These three tests measure related but genuinely different things, and NIDDK is explicit that they don’t always identify the same people. You can have a normal A1C and a prediabetes-range fasting glucose, or the reverse. The 2-hour OGTT tends to catch more people than A1C or fasting glucose alone, since it directly measures how your body handles a glucose load rather than a resting or averaged value. If your results across tests don’t match, that’s a known feature of how these tests work, not automatically a lab error.
Why there usually aren’t symptoms
Prediabetes typically produces no noticeable symptoms. Some people report mild fatigue, more frequent thirst, or subtle changes in energy after meals, but these are easy to miss or attribute to something else entirely. This is the central reason screening guidelines exist at all: waiting to feel something means waiting past the window where prediabetes is easiest to address.
Who should get screened
The ADA and CDC recommend screening for adults who are overweight or have obesity and have at least one additional risk factor, including a family history of type 2 diabetes, high blood pressure, low HDL or high triglycerides, a history of gestational diabetes, polycystic ovary syndrome, physical inactivity, or belonging to a higher-risk racial or ethnic group. Screening is also generally recommended for all adults starting at age 35, regardless of other risk factors, with earlier or more frequent testing depending on results and risk profile.
If you are researching fiber supplements after a glucose result, read what psyllium research shows about blood sugar and A1C. It explains the limits of the evidence and the medication questions to bring to your care team.
Prediabetes and metabolic syndrome
Prediabetes and metabolic syndrome are related but not identical. Metabolic syndrome is a broader 5-factor pattern that includes blood sugar as only one input alongside waist circumference, triglycerides, HDL, and blood pressure. You can have prediabetes without meeting the 3-of-5 metabolic syndrome threshold, and you can meet the metabolic syndrome threshold with blood sugar that’s still in the normal range. In practice, the two frequently show up together, since insulin resistance tends to sit behind both.
Can prediabetes be reversed?
Yes, and this is one of the better-established findings in this area. The landmark Diabetes Prevention Program trial found that structured lifestyle changes, modest weight loss and increased physical activity, reduced progression from prediabetes to type 2 diabetes by 58% overall, and by 71% in participants over age 60, outperforming metformin in that same trial. This is the evidence base behind the CDC’s National Diabetes Prevention Program, a structured lifestyle-change program available in many communities and often covered by insurance or Medicare.
What happens if it isn’t addressed
Prediabetes doesn’t turn into type 2 diabetes overnight, and not everyone with prediabetes progresses. But left unaddressed, a meaningful proportion of people do progress to type 2 diabetes over a period of years, which is why this window, however symptomless it feels, is treated as an important intervention point rather than something to watch passively.
The founder note
By the time I finally got a full lab panel, my own A1C wasn’t sitting in the prediabetes range anymore. It had already crossed into diabetes territory, alongside triglycerides over 1,700 and blood pressure high enough to alarm my physician. Prediabetes is the stage I blew straight past without ever being screened for it. If there’s one thing I’d tell someone in that 5.7% to 6.4% window: that’s the cheapest, easiest place in this entire process to make a change. I didn’t get that option. You still do.
Frequently asked questions
Can prediabetes be reversed without medication?
For many people, yes. The Diabetes Prevention Program trial showed lifestyle change alone outperforming medication for reducing progression risk, though individual results vary and some people benefit from combining both, under medical guidance.
How long does prediabetes typically last before becoming diabetes?
It varies significantly by individual, and not everyone with prediabetes progresses at all. Progression, when it happens, generally unfolds over several years rather than months, which is part of why it’s a meaningful window for change.
Can you have prediabetes at a normal weight?
Yes. Being overweight is the most common associated risk factor, but insulin resistance and elevated blood sugar can occur in people whose weight looks unremarkable, particularly with a family history or significant visceral fat despite normal total weight.
Does prediabetes cause any symptoms at all?
Usually not. When symptoms do appear, they tend to be subtle, mild fatigue or increased thirst, and are easy to attribute to something else. This is why routine screening matters more than waiting for a signal.
Is an A1C of 5.7% something to worry about?
It’s the low end of the prediabetes range and generally treated as an early signal worth acting on, not an emergency. See our dedicated breakdown of what an A1C of 5.7% means for the full picture.
The Metabolic Clarity takeaway
Prediabetes is one of the few diagnoses in medicine that comes with strong evidence it can actually be reversed, if it’s caught. The problem isn’t that prediabetes is untreatable. It’s that it’s silent, and silent problems only get addressed when someone goes looking for them on purpose.
Next step: Use the A1C and Average Glucose Calculator to see where your own number falls, then read the complete guide to A1C or the complete guide to insulin resistance for the mechanism behind the number.
Sources
- American Diabetes Association, Diagnosis and Classification of Diabetes: Standards of Care in Diabetes 2026
- CDC, Prediabetes: Your Chance to Prevent Type 2 Diabetes
- NIDDK, Preventing Type 2 Diabetes
- NIDDK, Diabetes Prevention Program (DPP)
Medical and regulatory disclaimer: This article is for general education only. It does not diagnose, treat, or prevent disease and does not replace advice from a physician or other qualified health professional. Do not start, stop, or change any medication based on this article. Talk to your doctor about screening and interpreting your own results.
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