Dark urine early in the morning: what to know

During sleep, the kidneys continue making urine while you take in no fluids. This can make the first urine darker yellow than later samples. A warm bedroom, sweating, alcohol the previous evening, or illness can increase concentration. Food dyes, vitamins and medicines may also change colour. Dark brown, red or cola-coloured urine is different from ordinary concentrated yellow urine. It can reflect blood, muscle breakdown or a liver and bile problem, so colour alone should not be used to identify the cause.

Drink normally after waking and observe the next few trips to the toilet rather than judging the first sample alone. Keep a note of colour, smell, pain and how often you pass urine. Avoid using excessive water to chase a colour change. Review vitamins, supplements and medicines with a pharmacist or clinician before stopping prescribed treatment. If the colour does not improve during the day or keeps returning, arrange an appointment.

Get urgent help if you pass almost no urine, feel confused or faint, have severe weakness, or cannot keep fluids down. Seek prompt review for visible blood, clots, tea-coloured urine, yellow eyes or skin, fever with side pain, or burning when urinating. Testing can check for concentration, infection, blood, kidney problems or liver-related changes.

Ask whether the colour fits overnight concentration and whether a urine test is needed. Tell the clinician about supplements, medicines, recent exercise, sweating, alcohol, pain, fever and any change in urine amount.