The most common early signs of diabetes are increased thirst, frequent urination (especially at night), unexplained weight loss, and fatigue that doesn’t improve with rest. Some people also notice blurred vision, slow-healing cuts, or recurring infections. But here’s the catch: type 2 diabetes often develops so gradually that many people have it for years without recognizing anything is wrong. The only way to know for certain is a blood test.
Symptoms That Show Up First
Both type 1 and type 2 diabetes share a core set of warning signs. When your blood sugar stays elevated, your kidneys work harder to filter the excess glucose, pulling more water with it. That’s why frequent urination and intense thirst tend to appear together. You may find yourself waking up multiple times at night to use the bathroom, or feeling thirsty no matter how much water you drink.
Other common symptoms include:
- Unexplained weight loss, even when you’re eating normally or more than usual
- Increased hunger, because your cells aren’t getting enough fuel from glucose
- Fatigue that feels disproportionate to your activity level
- Blurred vision, caused by fluid shifts in the lens of your eye
- Slow-healing cuts or wounds
- Genital itching or recurring yeast infections
The tricky part is that these symptoms overlap with dozens of other conditions, and some people with elevated blood sugar feel perfectly fine. That’s why screening matters even when you feel healthy.
How Type 1 and Type 2 Feel Different
Type 1 diabetes tends to announce itself dramatically. Symptoms can appear within weeks, sometimes days, and they escalate quickly. Children may suddenly start wetting the bed after years of staying dry. Adults might lose noticeable weight over a few weeks and feel increasingly weak or irritable. Because the body’s immune system is destroying the cells that produce insulin, blood sugar can spike to dangerous levels fast.
Type 2 diabetes is a slower process. Insulin resistance builds over months or years, and blood sugar creeps up gradually. Many people adapt to feeling slightly more tired or thirsty without connecting it to a medical problem. By the time symptoms become obvious enough to prompt a doctor visit, the disease may have been present for a long time. Roughly one in five people with type 2 diabetes don’t know they have it.
Skin Changes You Might Not Expect
Your skin can offer surprisingly specific clues. One of the most telling is dark, velvety patches that appear in body creases like the neck, armpits, or groin. This condition, called acanthosis nigricans, is strongly linked to insulin resistance and often shows up before a diabetes diagnosis. If you’ve noticed these patches and can’t explain them, it’s worth mentioning to your doctor.
Other skin signs include light brown or reddish round spots on your shins (sometimes called shin spots), which don’t hurt or itch but are common in people with diabetes. Recurring bacterial infections around the eyelids, hair follicles, or fingernails can also signal chronically elevated blood sugar, as can frequent fungal infections like athlete’s foot or jock itch. Persistently dry, itchy skin, particularly on the lower legs, may point to the poor circulation that comes with diabetes.
The Blood Tests That Confirm It
No combination of symptoms can diagnose diabetes on its own. You need one of three standard blood tests, and your doctor will typically confirm an abnormal result by repeating it on a separate day.
A1C test: This measures your average blood sugar over the past two to three months, expressed as a percentage. A result below 5.7% is normal. Between 5.7% and 6.4% indicates prediabetes. At 6.5% or higher, you meet the threshold for diabetes. No fasting is required, which makes this the most convenient option.
Fasting blood sugar test: You fast overnight, then have your blood drawn in the morning. A reading of 99 mg/dL or below is normal. Between 100 and 125 mg/dL falls in the prediabetes range. A result of 126 mg/dL or higher on two separate tests confirms diabetes.
Oral glucose tolerance test: After fasting, you drink a sugary solution and have your blood drawn two hours later. A two-hour reading of 200 mg/dL or above indicates diabetes. This test is less commonly used for general screening but plays a key role in diagnosing gestational diabetes during pregnancy.
What About Home Test Kits?
You can buy at-home A1C kits at most pharmacies, and they’re a reasonable starting point if you want a quick check before scheduling a doctor’s appointment. But their accuracy varies significantly. A University of Florida study tested several popular home kits against standard lab results and found wide differences. One brand (Home Access) had 82% of its samples fall within the acceptable accuracy range. Two other kits hit that mark only 46% and 29% of the time.
That means a home kit might give you a reassuring number when your actual A1C is in the prediabetes range, or it could alarm you unnecessarily. Use these kits as a rough signal, not a diagnosis. If your result comes back elevated, or if it’s normal but you still have symptoms, get a lab-based test through your doctor.
Who Should Get Screened Without Symptoms
The U.S. Preventive Services Task Force recommends screening for prediabetes and type 2 diabetes in adults aged 35 to 70 who are overweight or obese (a BMI of 25 or higher). If you’re in that group, you should be tested even if you feel completely fine.
Certain populations face higher risk and should consider screening earlier. Black, Hispanic/Latino, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander adults have disproportionately high rates of diabetes and may benefit from testing before age 35. Asian Americans should consider screening at a lower BMI threshold of 23 or above, because metabolic risk increases at lower body weights in this population.
A family history of diabetes, a history of gestational diabetes, or a diagnosis of polycystic ovary syndrome also moves you into the earlier-screening category. If any of these apply to you, don’t wait for symptoms to appear.
Screening During Pregnancy
Gestational diabetes develops during pregnancy and usually produces no noticeable symptoms. Most pregnant people are screened between 24 and 28 weeks with a glucose challenge test, where you drink a sugary solution and have your blood drawn one hour later. A result below 140 mg/dL is typically considered normal. A reading of 190 mg/dL or above means gestational diabetes.
If your result falls between those numbers, you’ll take a longer follow-up test that measures blood sugar at multiple time points. Two or more elevated readings on that test confirm the diagnosis. If you have risk factors like obesity, a previous gestational diabetes diagnosis, or a strong family history, your provider may screen you at your very first prenatal visit rather than waiting until the second trimester.
Prediabetes: The Warning Window
Prediabetes means your blood sugar is elevated but hasn’t crossed the diabetes threshold. An A1C between 5.7% and 6.4%, or a fasting glucose between 100 and 125 mg/dL, puts you in this category. About 80% of people with prediabetes don’t know they have it.
This matters because prediabetes is the stage where lifestyle changes have the most impact. Losing 5% to 7% of your body weight and getting about 150 minutes of moderate physical activity per week can reduce the risk of progressing to type 2 diabetes by more than half. If your numbers land in this range, you haven’t missed your window. You’ve found it.