Unexplained weight loss is a noticeable drop in body weight that occurs even if the person is not trying to lose weight through diet, exercise, or lifestyle changes. Unexplained weight loss can be a symptom of a serious condition or illness. For this reason, it is important to seek medical attention if anyone has weight loss that cannot be explained.

Causes of Unexplained Weight Loss

Potential causes of unexplained weight loss include:

  • Cancer
  • Addison’s disease (adrenal insufficiency)
  • Celiac disease
  • Changes in diet or appetite
  • COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
  • Crohn’s disease (a type of inflammatory bowel disease)
  • Dementia
  • Dental problems
  • Diabetes
  • Heart failure
  • Hypercalcemia
  • Hyperthyroidism (overactive thyroid)
  • Hypothyroidism (underactive thyroid)
  • Side effects of prescribed medications
  • Parkinson’s disease
  • Peptic ulcer
  • Substance abuse (alcohol, cocaine, other)
  • Tuberculosis
  • A parasitic infection
  • Undiagnosed eating disorders
  • Dysphagia (swallowing problems)
  • Swelling of the pancreas
  • Depression or anxiety

Diagnostic Tests

Tests that are commonly done to diagnose the cause of unexplained weight loss include:


  • Blood sugar (glucose) test
  • Complete blood count (CBC): A CBC can reveal evidence of infections, anemia (that can be caused by many conditions that result in unintentional weight loss), and more.
  • Thyroid panel
  • Liver function tests
  • Kidney function tests
  • Urinalysis
  • Tests for inflammation: Non-specific tests may include a sed rate and/or C-reactive protein.
  • Electrolytes: A sodium, potassium, calcium may give clues to an underlying problem
  • Endoscopy procedures such as an upper GI endoscopy or colonoscopy can look for evidence of gastrointestinal causes of weight loss.
  • Echocardiogram: An echocardiogram can be considered as an ultrasound of the heart, and is helpful in diagnosing many conditions, including infections present on the heart valves (infectious endocarditis).

Imaging tests that may be helpful include:

  • CT scan of the chest or abdomen
  • MRI
  • PET scan: A PET scan can look for evidence of metastases from cancer.

Treatment of unexplained Weight loss

The treatment of an unexplained weight loss depends upon the underlying cause. Some of the causes of unintentional weight loss are fairly uncommon, and diagnosis may require several visits to your doctor including providing your medical history and some basic tests.

Regardless of the cause, measures should be taken to treat the weight loss as well. When a cause is determined, the weight loss itself is sometimes neglected. If this is you, make sure to talk to your doctor about how you should treat this symptom.