Is dark, strong-smelling urine in the morning abnormal?

Upon waking, I often notice my urine is dark yellow and has a stronger smell than usual. Is this a sign of kidney problems or simply dehydration? (Hoang, 36, Hanoi)

Dark yellow, strong-smelling urine in the morning is not necessarily a sign of abnormality or impaired kidney function. After a long night's sleep, the body hasn't been rehydrated for many hours. This causes urine to become more concentrated, appearing dark yellow with a more pronounced odor compared to other times of the day. If this condition only occurs in the morning, and urine returns to a light yellow color after adequate water intake without other unusual symptoms, it is generally not a cause for concern.

Beyond insufficient water intake, certain foods or medications can also alter urine color and smell. However, if urine remains consistently dark yellow, develops an unusual foul odor, or shows a significant change from its previous state, individuals should pay attention to accompanying symptoms to identify the cause.

Traditional East Asian medicine posits that the kidneys play a crucial role in Qi transformation activities, working with the bladder to regulate urine excretion. If dark yellow, strong-smelling urine in the morning is accompanied by a burning sensation, painful urination, or frequent urination, it may indicate conditions related to the urinary tract. For instance, a urinary tract infection can cause unpleasant-smelling urine, along with painful urination, urinary urgency, frequent urination, or lower abdominal pain. Early-stage kidney disease, however, sometimes presents without clear symptoms. Therefore, kidney function cannot be assessed solely based on urine color or smell.

To determine kidney function, doctors may order specific tests, such as glomerular filtration rate assessment and urine tests, depending on the individual's condition.

To reduce urine concentration in the morning, individuals should drink sufficient water throughout the day, adjusting intake according to their body's needs and health status. If symptoms persist, recur, or are accompanied by leg or face swelling, blood in the urine, abnormally decreased urine output, or unexplained fatigue, individuals should seek evaluation at a healthcare facility.