A blood sugar of 87 mg/dL is not low. It falls squarely in the normal range for fasting blood glucose, which is anything below 100 mg/dL. Low blood sugar, clinically called hypoglycemia, doesn’t begin until levels drop below 70 mg/dL. At 87, you have a comfortable 17-point margin above that threshold.
Where 87 Falls in the Normal Range
Fasting blood sugar below 100 mg/dL is considered normal. Between 100 and 125 mg/dL is prediabetes, and 126 mg/dL or higher on two separate tests indicates diabetes. At 87, your reading sits right in the middle of the healthy zone, not near either boundary.
For people with diabetes who are managing their blood sugar with medication, the American Diabetes Association recommends a pre-meal target of 80 to 130 mg/dL. A reading of 87 is near the lower end of that window but still within goal. Even during pregnancy, where targets are tighter, the recommended fasting range is 70 to 95 mg/dL, placing 87 comfortably in bounds.
Why You Might Feel “Off” at 87
Some people notice mild symptoms like shakiness, lightheadedness, or hunger at blood sugar levels that are technically normal. This can happen if your body is accustomed to running higher. If your blood sugar has been consistently above 150 or 200 mg/dL, a sudden drop to 87 can feel like a low even though it isn’t one. Your body recalibrates over time, and these sensations usually fade as you spend more time in the normal range.
Reactive hypoglycemia is another possibility. This is when blood sugar drops after a meal, typically within four hours of eating. Some people experience symptoms that feel like low blood sugar after eating high-carbohydrate meals, even when their glucose doesn’t technically dip below 70. If you consistently feel shaky or foggy a few hours after meals, that pattern is worth discussing with a doctor, but a single reading of 87 on its own is not a concern.
What Actual Low Blood Sugar Looks Like
True hypoglycemia starts below 70 mg/dL. At that level, you may notice shakiness, sweating, a fast heartbeat, irritability, or difficulty concentrating. As blood sugar drops further into the 50s or below, symptoms become more serious: confusion, blurred vision, difficulty speaking, and in extreme cases, loss of consciousness. These are situations that require immediate action, like eating fast-acting carbohydrates.
For people without diabetes, blood sugar rarely drops low enough to cause these symptoms. The body has several backup systems, including releasing stored glucose from the liver, to keep levels stable. Hypoglycemia is most common in people taking insulin or certain diabetes medications that actively push blood sugar down.
Your Meter May Not Be Perfectly Precise
Home glucose monitors are allowed a margin of error of up to 15% from laboratory readings. That means a meter displaying 87 mg/dL could reflect an actual value anywhere from roughly 74 to 100 mg/dL. Even at the low end of that range, you’re still above the 70 mg/dL hypoglycemia threshold. But it’s worth keeping this variability in mind if you’re getting readings that seem inconsistent or surprising. Factors like unwashed hands, expired test strips, and extreme temperatures can all affect accuracy.
After a Meal vs. Fasting
When you took the reading matters. A fasting blood sugar of 87 is perfectly normal. A reading of 87 two hours after a large meal is actually quite good, since post-meal glucose can rise well above 100 in healthy people and the general guideline is simply to stay under 180 mg/dL at the two-hour mark. If anything, 87 after eating suggests your body is processing glucose efficiently.
If you saw 87 on a continuous glucose monitor during the night or between meals, that’s also unremarkable. Blood sugar naturally fluctuates throughout the day, and dipping into the 80s during fasting periods is exactly what a healthy metabolism does.