My urine is always dark yellow: what should I know?

Urine becomes deeper yellow when it contains less water. Hot weather, sweating, vomiting, diarrhoea, exercise, or a long period without drinking can contribute to dehydration. Vitamins and some medicines can also alter urine colour. Dark yellow is different from brown, red, or tea-coloured urine, which needs a separate assessment. Look for thirst, a dry mouth, headache, dizziness, or passing urine less often. Yellowing of the eyes or skin, pale stools, nausea, or pain under the right ribs can point away from simple concentration and should be discussed with a clinician.

Drink fluids regularly and let thirst guide you, unless a clinician has told you to restrict fluids. Take smaller, frequent sips if you feel nauseated. Notice whether the colour becomes lighter and record any new pain, fever, vomiting, bowel changes, or medication and supplement use. Avoid treating the colour alone with leftover antibiotics or stopping a prescribed medicine without advice. If heat exposure caused heavy sweating, move somewhere cool and consider medical advice for possible heat exhaustion.

Arrange a medical review if the colour remains dark despite drinking normally, keeps returning without an obvious reason, or comes with burning, fever, flank pain, marked tiredness, or reduced urine. Seek urgent help for confusion, fainting, inability to keep fluids down, severe weakness, or signs of heat illness. Urgent assessment is also sensible for brown or tea-coloured urine, blood, yellow eyes or skin, or severe abdominal pain.

Ask whether your symptoms fit dehydration, whether a urine test or blood tests are appropriate, and whether any medicine or supplement could explain the colour. Mention your usual fluid intake, recent heat or illness, urinary symptoms, and changes in your eyes, skin, stools, or appetite.