The early signs of prediabetes are usually invisible: most people have no symptoms at all. When a clue does show up, it is often darkened, velvety skin on the neck, armpits or groin. Because the condition is so quiet, the most reliable early signs are your risk factors and a blood test showing a fasting glucose, A1C or two-hour glucose result that is above normal but below the diabetes range.
Key takeaways
- About 115 million American adults have prediabetes, and about 8 in 10 of them do not know it (CDC).
- The one visible sign some people get is darkened skin in body folds, called acanthosis nigricans.
- Thirst, frequent urination, blurred vision and tiredness usually mean blood sugar has climbed higher, possibly into the type 2 diabetes range.
- Prediabetes is diagnosed with an A1C, fasting glucose or glucose tolerance test. Canadian and US cut-offs differ slightly.
- Losing 5 to 7% of body weight and getting 150 minutes of activity a week lowered type 2 diabetes risk by 58% in the National Diabetes Prevention Program.
What are the early signs of prediabetes?
Prediabetes means your blood sugar is higher than normal but not yet high enough to be called type 2 diabetes. According to the Mayo Clinic, it often has no clear symptoms. Many people only find out after a routine blood test, or years later when type 2 diabetes has developed.
The one physical clue that doctors look for is acanthosis nigricans: patches of darker, sometimes velvety skin on the back of the neck, in the armpits or in the groin. It looks dark brown or black on brown or Black skin, and light brown or tan on white skin. It is linked to insulin resistance, the process that usually sits behind prediabetes.
If you notice this kind of skin change, it is not a diagnosis on its own. It is a good reason to ask your doctor for a blood sugar test.
Signs that blood sugar may have moved into the diabetes range
The Mayo Clinic lists the following as signs that prediabetes may have progressed to type 2 diabetes. If you have any of them, book a medical appointment rather than waiting for your next check-up.
- Feeling more thirsty than usual
- Urinating more often, including at night
- Feeling hungrier than usual
- Tiredness
- Blurred vision
- Numbness or tingling in the hands or feet
- Frequent infections
- Sores that are slow to heal
- Weight loss without trying
Prediabetes warning signs you can't feel: the risk factors
Since prediabetes rarely causes symptoms, your personal risk factors are the most useful early warning. The CDC and Mayo Clinic list these as the main ones:
- Extra weight, especially around the belly. Mayo Clinic flags a waist over 40 inches for men and over 35 inches for women.
- Age. The CDC lists age 45 or older as a risk factor, and risk rises with age.
- Family history. A parent, brother or sister with type 2 diabetes.
- Low activity. Being physically active fewer than three times a week.
- Pregnancy history. Gestational diabetes, or giving birth to a baby over 9 pounds.
- Polycystic ovary syndrome (PCOS).
- Obstructive sleep apnea and smoking.
- Heart and cholesterol markers. High blood pressure, low HDL ("good") cholesterol or high triglycerides.
- Ancestry. People of African, Hispanic/Latino, Indigenous, Pacific Islander and some Asian backgrounds have a higher risk.
The more of these that apply to you, the more important it is to get tested, even if you feel perfectly well.
Alongside testing and lifestyle changes, some people like to add a herbal supplement to their routine. Naavudi blood sugar support combines nine traditional Ayurvedic herbs, including bitter melon, fenugreek and gurmar, with our fulvic mineral extract, and is designed to support healthy blood sugar levels as part of a balanced diet and active lifestyle. It is currently available as a Buy 2 Get 1 Free offer. It is not a replacement for testing, medical care or any prescribed medication.
Prediabetes numbers: A1C, fasting and 2-hour glucose ranges
Prediabetes is diagnosed with a blood test, not by symptoms. Your doctor may order one or more of the tests below. Note that the American Diabetes Association and Diabetes Canada use slightly different lower cut-offs.
| Test | Normal | Prediabetes (ADA, US) | Prediabetes (Diabetes Canada) | Diabetes range |
|---|---|---|---|---|
| A1C (average over about 3 months) | Below 5.7% | 5.7% to 6.4% | 6.0% to 6.4% | 6.5% or higher |
| Fasting plasma glucose | Below 100 mg/dL (5.6 mmol/L) | 100 to 125 mg/dL (5.6 to 6.9 mmol/L) | 6.1 to 6.9 mmol/L | 126 mg/dL (7.0 mmol/L) or higher |
| 2-hour glucose after a 75 g drink (OGTT) | Below 140 mg/dL (7.8 mmol/L) | 140 to 199 mg/dL (7.8 to 11.0 mmol/L) | 7.8 to 11.0 mmol/L | 200 mg/dL (11.1 mmol/L) or higher |
For a fuller look at everyday readings, including after-meal targets, see our guide to normal blood sugar levels for fasting, after meals and A1C.
How do I know if I have prediabetes?
The only way to know is to get tested. If you are in Canada, Diabetes Canada's screening guideline recommends testing at least every three years from age 40, and earlier or more often if you have risk factors. In the US, the CDC offers a free one-minute prediabetes risk test, and a high score should be followed by a blood test from your doctor.
- Check your risk factors against the list above.
- Ask for an A1C or fasting glucose test at your next appointment, or sooner if several risk factors apply.
- Get a repeat test if your result is borderline. Doctors usually confirm results before giving a diagnosis.
- Write down your numbers so you can track change over time.
What to do after spotting early signs of prediabetes
Prediabetes is a warning, not a verdict. According to the CDC, the National Diabetes Prevention Program lowered the risk of developing type 2 diabetes by 58%, and by 71% for people over 60. The two main goals in that program are:
- Losing about 5 to 7% of body weight (10 to 14 pounds for someone who weighs 200 pounds).
- Getting at least 150 minutes a week of brisk walking or similar activity.
Small habits add up. A short stroll after meals is one of the easiest places to start; our article on walking after eating and blood sugar explains how long to walk and when. Eating more fibre-rich vegetables, beans and whole grains, cutting back on sugary drinks and getting enough sleep also help.
If you are curious about traditional herbs used to support healthy blood sugar, read what the research says about bitter melon, fenugreek and gurmar. Always tell your doctor about any supplement you take, and keep taking any prescribed medication.
Frequently asked questions
Can you have prediabetes and feel completely normal?
Yes. Most people with prediabetes have no symptoms at all, which is why about 8 in 10 people who have it do not know, according to the CDC. A blood test is the only reliable way to find out.
What A1C level is considered prediabetes?
The American Diabetes Association defines prediabetes as an A1C of 5.7% to 6.4%. Diabetes Canada uses 6.0% to 6.4%. An A1C of 6.5% or higher is in the diabetes range.
Is prediabetes reversible?
Prediabetes does not always lead to type 2 diabetes. In the CDC-led National Diabetes Prevention Program, structured lifestyle changes lowered the risk of developing type 2 diabetes by 58%, or 71% for people over 60. Ask your doctor how often to recheck your numbers.
How often should I get my blood sugar checked?
Diabetes Canada recommends that adults 40 and older be tested at least every three years, and more often or earlier if they have risk factors. Your doctor may suggest testing every 6 to 12 months if your risk is very high.
The bottom line on early signs of prediabetes
The early signs of prediabetes are easy to miss because most people feel fine. Watch for darkened skin in body folds, take your risk factors seriously and ask for an A1C or fasting glucose test. Catching high-normal numbers early gives you the best chance to change course with your doctor's help.
Sources
- CDC: Prediabetes: Your Chance to Prevent Type 2 Diabetes
- Mayo Clinic: Prediabetes symptoms and causes
- American Diabetes Association: Diagnosis
- Diabetes Canada: Screening and diagnosis algorithm
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Looking for natural blood sugar support? Naavudi is a practitioner-formulated herbal supplement that combines nine traditional Ayurvedic herbs, including bitter melon, fenugreek, gurmar, Java plum and holy basil, with our fulvic mineral extract. It is designed to support healthy blood sugar levels as part of a balanced diet and active lifestyle, and has been made in Canada since 2009.
This article is general information, not medical advice. If you have diabetes or take medication that lowers blood sugar, talk to your doctor or pharmacist before starting any supplement, and never stop or change a prescribed medication without medical advice.