Your morning coffee might actually change the smell of your urine — and here’s why this surprising phenomenon has both doctors and coffee lovers curious.

Every morning, millions of people start their day with a steaming cup of coffee. For most, it’s a comforting ritual they can’t skip. But few realize that this beloved drink can have an unexpected effect on the body. According to doctors, coffee can actually alter the odor of your urine.

This phenomenon is real, and more and more people are noticing it. Some detect a strong or unusual smell after drinking coffee, while others never make the connection. Yet science has a simple explanation.

Why coffee changes the smell of urine

Coffee contains several volatile compounds. Once ingested, these compounds quickly enter the bloodstream, are filtered by the kidneys, and then eliminated through urine. The result? A stronger — and sometimes unpleasant — odor.

Caffeine also acts as a diuretic, meaning it makes you urinate more often. That increased frequency can make the scent more noticeable, as the concentration of odor-causing compounds in the urine rises. If coffee is consumed on an empty stomach, the smell can become even more intense.

Some coffee drinkers describe the odor as metallic, while others notice bitter or acidic notes. The effect is temporary but can be surprising. It also depends on the quality of the coffee, how often it’s consumed, and how hydrated your body is.

Should you be worried?

In most cases, no. A stronger smell after drinking coffee isn’t a sign of illness — it’s simply a normal metabolic reaction. However, if the change is sudden, persistent, or accompanied by other symptoms, it’s a good idea to check with a healthcare professional.

People’s sensitivity to smell varies. Some notice it immediately, while others don’t perceive any difference at all. Diet also plays a role — high-protein or spicy foods can intensify the effect.

To reduce the odor, the easiest solution is to stay well-hydrated. Drinking water before or after your coffee helps dilute your urine, making the smell less noticeable or even undetectable.

Another tip: choose higher-quality coffee that’s lightly roasted and free of additives. This reduces the presence of harsh-smelling compounds. And as always, listen to your body — if the smell bothers you, simply cutting back on coffee might be enough.

The bottom line

While coffee offers plenty of benefits, it can also lead to a few surprising side effects — and urine odor is one of them. It’s not a mystery or a health warning, just a reminder that everything we consume has an impact on our bodies.