A popcorn-like smell in urine is not a formal medical term, but people often use it to describe a sweet, nutty, or slightly buttery odor. The most common explanation for this kind of smell is the presence of ketones in the urine. Ketones are substances the body produces when it burns fat instead of sugar for energy.
This can happen during fasting, low-carbohydrate diets, dehydration, prolonged exercise, or when blood sugar is not being used properly. One of these ketones, acetone, has a sweet smell that different people may describe in different ways, including popcorn-like. Smell perception varies a lot from person to person, which explains why the same urine odor can be described so differently.
Rare genetic conditions can also cause sweet-smelling urine, but these typically appear in infancy or early childhood and come with other serious symptoms. In adults, diet, hydration status, and metabolic changes are far more likely causes. A brief change in urine smell without other symptoms is usually not dangerous.
If the smell is persistent or comes with excessive thirst, frequent urination, weight loss, nausea, or fatigue, medical evaluation is important. Avoid self-diagnosing or changing medications on your own, and consider seeing a primary care doctor or urologist for proper testing and guidance