Being prediabetic means your blood sugar levels are higher than normal but not yet high enough to qualify as Type 2 diabetes. It’s a warning stage, one that affects more than 115 million American adults, over 2 in 5. The striking part: 8 in 10 people with prediabetes don’t know they have it, largely because the condition rarely causes obvious symptoms. Without changes, many people with prediabetes develop Type 2 diabetes within five years.
The good news is that prediabetes is reversible. Understanding what’s happening inside your body, how it’s detected, and what actually works to bring blood sugar back to normal puts you in a strong position to act early.
How Prediabetes Is Diagnosed
Three blood tests can identify prediabetes, and any one of them is enough for a diagnosis:
- A1C test: Measures your average blood sugar over the past two to three months. A result between 5.7% and 6.4% indicates prediabetes. (Normal is below 5.7%; diabetes is 6.5% or higher.)
- Fasting blood glucose: Taken after an overnight fast. A reading of 100 to 125 mg/dL falls in the prediabetic range.
- Oral glucose tolerance test (OGTT): Measures blood sugar two hours after drinking a sugary solution. A result between 140 and 199 mg/dL signals prediabetes.
The U.S. Preventive Services Task Force recommends screening for adults aged 35 to 70 who are overweight (BMI of 25 or higher). If you’re Asian American, screening is recommended at a lower BMI of 23 or above. For Black, Hispanic/Latino, American Indian/Alaska Native, and Native Hawaiian/Pacific Islander adults, earlier screening may be appropriate because these populations face disproportionately higher rates of diabetes. Repeat screening every three years is the general recommendation.
What’s Happening in Your Body
Prediabetes comes down to two related problems: your cells stop responding normally to insulin, and the organ that makes insulin starts struggling to keep up.
Insulin is the hormone that tells your cells to absorb sugar from the bloodstream. When cells become resistant to that signal, your pancreas compensates by producing more insulin. For a while, this extra effort keeps blood sugar in check. But over time, the insulin-producing cells in the pancreas wear down. They can’t manufacture enough insulin to overcome the resistance, and blood sugar starts creeping up.
The two forms of prediabetes involve slightly different patterns. In one form (called impaired fasting glucose), the main issue is that the liver doesn’t respond well to insulin and releases too much stored sugar overnight. In the other form (impaired glucose tolerance), both muscle tissue and insulin production are impaired, so your body struggles to clear sugar from the blood after meals. Many people have elements of both.
Here’s what makes prediabetes tricky: even a small, persistent rise in blood sugar damages the insulin-producing cells further. Researchers have shown that an increase as modest as 16 mg/dL in average daily blood sugar can significantly impair insulin release. This creates a self-reinforcing cycle where slightly elevated sugar causes more damage, which causes even higher sugar. That’s why early intervention matters so much.
Signs and Symptoms
Prediabetes is almost entirely silent. Most people feel completely normal, which is exactly why so many cases go undetected. There are no headaches, no fatigue spikes, and no warning pains that reliably signal the condition.
One physical sign worth knowing about: dark, velvety patches of skin that appear in body creases like the neck, armpits, or groin. This condition, called acanthosis nigricans, is a visible marker of insulin resistance and is common in people with prediabetes or obesity. The patches can also show up on your hands, elbows, or knees. Not everyone with prediabetes develops them, but if you notice these changes, they’re worth mentioning to your doctor.
Why It Matters Beyond Diabetes
Prediabetes isn’t just a pit stop on the road to diabetes. Even at this stage, your cardiovascular system is already feeling the effects. A large meta-analysis published in The BMJ found that people with prediabetes face a 10% to 20% higher risk of coronary heart disease and a 6% to 20% higher risk of stroke compared to people with normal blood sugar, depending on how prediabetes is defined and measured.
These aren’t dramatic spikes in risk, but they’re meaningful, especially because they compound over years. Blood sugar levels in the prediabetic range promote inflammation in blood vessel walls and contribute to the buildup of arterial plaque. This damage accumulates quietly alongside the metabolic changes that eventually lead to full diabetes.
How to Reverse Prediabetes
Prediabetes responds remarkably well to lifestyle changes. The landmark Diabetes Prevention Program trial, one of the largest and longest studies on the subject, tracked participants for 21 years. People who made intensive lifestyle changes reduced their rate of developing diabetes by 24% over that entire period compared to a placebo group. Those changes boiled down to two things: moderate weight loss and regular physical activity.
You don’t need to lose a dramatic amount of weight. Losing just 7% of your body weight, about 14 pounds for someone who weighs 200, is enough to bring blood sugar levels back into the normal range for many people. The physical activity target used in the study was 150 minutes per week of moderate exercise, which works out to about 30 minutes of brisk walking five days a week.
These numbers are achievable, not extreme. The key is consistency over months rather than intensity over weeks. Your body needs sustained lower blood sugar levels to allow the insulin-producing cells in the pancreas to recover from the damage caused by that self-reinforcing cycle of elevated glucose.
When Medication Enters the Picture
For some people, lifestyle changes alone aren’t enough or aren’t practical. Metformin, the most commonly studied medication for prediabetes, reduced diabetes incidence by 17% over the same 21-year follow-up period. It’s less effective than lifestyle intervention for most people, but there’s one notable exception: in women with a history of gestational diabetes (diabetes during pregnancy), metformin cuts diabetes risk by 50%, matching the benefit of lifestyle changes. Three-year screening intervals with either lifestyle changes, metformin, or both is the approach recommended by major clinical guidelines for people with prediabetes.
What Reversal Actually Looks Like
Reversing prediabetes doesn’t happen overnight, and it isn’t a one-time fix. The process typically takes several months of sustained changes before blood tests show your numbers have dropped back into the normal range. Your A1C reflects a rolling average over roughly three months, so that’s the minimum window before you’d see meaningful movement on that test.
Reversal also doesn’t mean you’re permanently in the clear. The metabolic tendencies that led to prediabetes, including how your body handles insulin, are influenced by genetics, age, and body composition. If the lifestyle habits that brought your numbers down slip away, blood sugar can drift back up. People who have had prediabetes benefit from regular monitoring even after their levels normalize, which is part of why three-year screening intervals remain the standard recommendation.