Iron deficiency and anaemia
Iron is needed to make haemoglobin, which carries oxygen. When iron stores or haemoglobin fall, patients may feel tired, weak, short of breath, light-headed or aware of their heartbeat. Heavy periods, pregnancy, gastrointestinal blood loss, restricted diets and poor absorption are important clues. Iron deficiency must also prompt the question: why is the iron low?
Vitamin D deficiency
Severe vitamin D deficiency can affect bones and muscles and may cause muscle weakness or pain that patients describe as low energy. However, fatigue by itself does not prove vitamin D deficiency, and trials have not shown that vitamin D is a universal energy treatment. Testing and replacement should be based on clinical risk and context.
Magnesium deficiency
True magnesium deficiency may cause fatigue, weakness, poor appetite, nausea, cramps, tingling or abnormal heart rhythms. Risk is higher with gastrointestinal disease, uncontrolled diabetes, long-term alcohol use and some medicines. Routine high-dose magnesium is not the answer to every fatigue complaint and may be unsafe in significant kidney disease.
Hypothyroidism
Thyroid hormone helps regulate how the body uses energy. An underactive thyroid can cause tiredness, cold intolerance, constipation, dry skin, hair changes and some weight gain. These symptoms are nonspecific, so diagnosis requires thyroid blood tests—usually TSH and, when appropriate, free T4—not symptoms alone.
Vitamin B12, folate and nutrition
Vitamin B12 or folate deficiency may cause anaemia, fatigue and other symptoms; B12 deficiency can also cause numbness, balance problems or cognitive changes. Very low calorie or protein intake, especially during rapid weight loss, may reduce energy and contribute to weakness or hair shedding.
Diabetes and glucose problems
High glucose can cause tiredness, thirst, frequent urination and blurred vision. Low glucose may cause sweating, shaking, palpitations, confusion and weakness. Patients using insulin or medicines that can cause hypoglycaemia should review the timing of symptoms with glucose records.
Sleep, mood, medicines and other medical causes
Insomnia, obstructive sleep apnoea, shift work, depression, anxiety, infection, inflammatory disease, heart or lung disease and many medicines can cause fatigue. Loud snoring, witnessed pauses in breathing or morning headaches should raise concern about sleep apnoea, especially when weight or high blood pressure is also present.
What tests might be considered?
There is no single “fatigue panel.” Depending on the history and examination, a clinician may consider a blood count, ferritin or iron studies, thyroid tests, glucose or HbA1c, kidney and liver tests, vitamin B12, folate, vitamin D or magnesium. Not every patient needs every test.
How can I prepare for a fatigue consultation?
Bring a brief timeline of your tiredness, recent reports and a complete list of medicines, supplements and doses. Note how symptoms affect daily activities and use the checklist in this article to record other changes.
Questions to ask at your appointment
- What could explain my tiredness, based on my symptoms and examination?
- What do my existing results and medicines tell us?
- Which tests, if any, would help answer the next clinical question?
Do not start thyroid medicine or change a prescribed dose without advice from your treating clinician.
Lahore appointments: Zain 0333 8288400 or Wajid 0319 4631615. Both answer booking calls and WhatsApp enquiries from 08:00 to 23:00 Pakistan time. These are reception hours, not the doctor's consultation schedule.
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Visit-preparation information added 5 October 2026.
Primary sources
- World Health Organization: Anaemia fact sheet, updated February 2025.
- NIH Office of Dietary Supplements: Iron, accessed July 2026.
- NIH Office of Dietary Supplements: Vitamin D, updated June 2025.
- NIH Office of Dietary Supplements: Magnesium, accessed July 2026.
- American Thyroid Association: Hypothyroidism, accessed July 2026.
- NIDDK: Hypothyroidism, consulted October 2026 for thyroid assessment and medicine guidance.
This article is educational. Persistent or function-limiting fatigue deserves an individual medical assessment rather than self-treatment with supplements.