What should you know about dark heavy urine?

People may describe urine as heavy when it looks dark, smells stronger or seems denser. Concentration commonly increases after sweating, vomiting, diarrhoea or simply drinking less. Foods, supplements and medicines can alter colour or smell as well. If the urine is genuinely dark and you also have yellow skin or eyes, pale stools, nausea, itching or unusual tiredness, a liver-related illness such as hepatitis A or hepatitis B should be considered by a clinician. Burning, pain or reduced urine points to a different set of concerns. The description alone cannot establish a diagnosis.

Check a fresh sample in good light and a clean container. Drink water at regular intervals if you have no fluid restriction, and consider recent heat exposure or other fluid loss. Keep a note of colour, smell, volume, medicines, supplements and associated symptoms. Do not stop prescribed medicines without advice. If the appearance improves after normal hydration and does not return, continue observing; otherwise arrange a clinical review.

Seek urgent help if you are confused, faint, severely weak, unable to drink, passing very little urine, in severe pain, or feverish and very unwell. Prompt medical assessment is appropriate for persistent dark urine, repeated changes without a clear trigger, yellowing of the skin or eyes, pale stools, vomiting or abdominal pain. A clinician can distinguish concentration from a urinary or liver-related problem.

Does my description suggest concentration, pigment or another cause? Could my current medicines be involved? Would urine or blood testing help, and what should I do if the colour changes again?