Early signs of prediabetes: how to know you're at risk.

What prediabetes actually is

Prediabetes is the in-between zone where your blood sugar is higher than normal but not yet in the type 2 diabetes range. Two main blood markers are used to define it: [VERIFY: ADA diagnostic criteria reference]

• A1C between 5.7 and 6.4 percent
• Fasting plasma glucose between 100 and 125 mg/dL

It is common. According to the CDC (Centers for Disease Control and Prevention) diabetes section, a large share of American adults are in this zone, and many do not know it. [VERIFY: stat, confirm the current CDC prevalence figure before quoting a specific number]

The reason this matters: prediabetes is when your body is starting to handle sugar less efficiently, often years before any of the harder consequences show up. It is also the window where small daily habits can meaningfully change your trajectory.

Why it usually does not feel like anything

This is the part that surprises people. Prediabetes is mostly silent. You can be sitting comfortably in the 5.9 to 6.4 percent A1C range for years without a single dramatic symptom. There is no fever, no pain, no obvious "off" feeling.

That is part of why it goes undiagnosed. Adults often only learn about it after a routine physical, or after looking back from a type 2 diagnosis and realizing the A1C had been creeping up for half a decade.

So if you are reading this and waiting for symptoms before testing, you are working with the wrong tool. The right tool is a blood test, and the right time is at a routine physical.

The risk factors worth knowing

Risk factors are different from symptoms. They do not tell you that you have prediabetes; they tell you that your odds are higher than average and that testing is worth doing. The CDC diabetes section publishes the current consensus list.

The big ones, roughly in order of how much weight they carry:

• Age 35 and up. Risk climbs with age, even in people who feel perfectly healthy.
• Family history. A parent or sibling with type 2 diabetes is one of the strongest signals.
• Excess weight, particularly around the midsection. Body composition matters more than the number on the scale.
• A sedentary routine. Most days with little structured movement.
• Sleep apnea or chronic poor sleep. Sleep affects insulin sensitivity more than most people realize.
• Polycystic ovary syndrome (PCOS).
• History of gestational diabetes.
• High blood pressure or out-of-target cholesterol. Metabolic markers travel together.
• Race and ethnicity. Risk is higher in Black, Hispanic, American Indian, Pacific Islander, and some Asian American populations.

If two or three of those apply to you, get a baseline A1C done at your next physical, even if you feel fine. Especially if you feel fine.

Subtle signs some people do notice

While prediabetes is mostly silent, a handful of low-volume clues sometimes show up. They are not specific enough to make a diagnosis, but they are reasons to ask for a test:

• Energy crashes an hour or two after meals, especially after carb-heavy ones.
• Increased thirst or frequent urination, particularly waking up to use the bathroom at night.
• Slow-healing small cuts or scratches.
• Darker, velvety patches of skin in folds (back of the neck, armpits, groin), called acanthosis nigricans.
• More frequent yeast or urinary infections. Higher glucose creates conditions some microbes prefer.
• Tingling or numbness in feet or hands. Less common in true prediabetes, more common as glucose drifts higher.

None of these are conclusive on their own. They are reasons to test.

The numbers your doctor uses

Three tests can confirm prediabetes. Your provider will usually pick one or two:

1. A1C. A single number that estimates your average blood sugar over the last three months. The prediabetes range is 5.7 to 6.4 percent.
2. Fasting plasma glucose. A blood draw after at least eight hours without food. Prediabetes range is 100 to 125 mg/dL.
3. Oral glucose tolerance test (OGTT). You drink a sweet glucose solution and your blood is checked at two hours. Prediabetes range is 140 to 199 mg/dL at two hours.

If you would rather not wait for an appointment to start gathering data, two things you can do today are an at-home A1C kit (good for a trend) and a continuous glucose monitor for two weeks (great for seeing your real-life patterns). For background, see our pillars on what a CGM is and the supporting article at-home A1C test accuracy.

What to do if you suspect prediabetes

A few practical next steps, in order of usefulness:

1. Schedule a check-up. Ask specifically for an A1C and a fasting glucose. Most providers will run them as part of routine bloodwork if you mention you are curious about metabolic health.
2. Track one number at home. Either a quarterly home A1C or two weeks with a CGM. You will know more about your own body in a month than from years of single annual readings.
3. Add a short walk after your biggest meal. Ten to fifteen minutes of walking after eating reliably blunts the post-meal glucose climb in research. See the CDC diabetes section for general physical activity guidance.
4. Sleep first, supplements second. Inadequate sleep nudges insulin sensitivity in the wrong direction. Better sleep almost always beats a new supplement bottle.
5. Add fiber to most meals. Beans, oats, lentils, berries, vegetables, psyllium. Soluble fiber consistently lowers post-meal glucose spikes.
6. Lift something heavy a few times a week. Muscle is a glucose sink. The more skeletal muscle you carry, the better your body handles sugar.
7. Talk about medications with your provider. In some people with prediabetes, metformin is part of the conversation. That is between you and your prescriber.

A note about words

We deliberately do not use words like "cure," "reverse," or "prevent" on this site. Prediabetes is not a switch. Habits genuinely matter, and they can change the trajectory in real ways, but no single thing flips it off. Honesty about that is more useful than promises that do not survive contact with biology.

Common questions

Can you have prediabetes and feel completely fine?

Yes, very much so. The majority of adults with prediabetes report no symptoms at all. The condition is defined by lab numbers, not by how you feel.

How often should I get tested?

If you have one or more risk factors, most clinical guidance suggests yearly. If you have a clean baseline, every three years is a common recommendation for adults 35 and older. Your provider will tailor this to your situation.

Is prediabetes always a path to type 2 diabetes?

Not always. A meaningful portion of adults with prediabetes do not progress to type 2 within ten years, particularly those who make sustained lifestyle changes. The trajectory is not fixed.

Can a CGM diagnose prediabetes?

No. A CGM shows your real-life glucose patterns, which can strongly suggest something is off, but the formal diagnosis still requires a clinical lab test (A1C, fasting glucose, or oral glucose tolerance test).

Does losing weight always help?

For many adults with prediabetes carrying excess weight, modest weight loss has meaningful effects on insulin sensitivity. But not every case of prediabetes is driven by weight, and the goal is metabolic health, not a number on a scale.

References

1. American Diabetes Association. Diagnosis criteria for prediabetes and diabetes. diabetes.org. [VERIFY: link to current standards of care]
2. Centers for Disease Control and Prevention. Diabetes. cdc.gov/diabetes.
3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes overview hub. niddk.nih.gov/health-information/diabetes.
4. [VERIFY: CDC National Diabetes Statistics Report, current edition]
5. [VERIFY: cite a post-meal walking meta-analysis]

Last reviewed: May 25, 2026.

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