Hypothyroidism, underactive thyroid


Hypothyroidism symptoms can vary widely among individuals and often mimic those of other health conditions, making it challenging to diagnose based solely on symptoms. Instead, diagnosis is typically confirmed through a series of blood tests. 

Initial testing: 

The primary test for diagnosing hypothyroidism is the thyroidstimulating hormone (TSH) level check. Elevated TSH levels may indicate hypothyroidism, prompting a retest along with a measurement of the thyroid hormone T4. A diagnosis of hypothyroidism is generally confirmed if TSH levels are high and T4 levels are low. In some cases, thyroid hormone T3 is also measured. 

Subclinical hypothyroidism: 

If a second test indicates high TSH but normal T4 and T3 levels, the condition is likely subclinical hypothyroidism, which typically does not produce noticeable symptoms. 

Ongoing management: 

TSH tests are crucial for ongoing management of hypothyroidism, helping health care providers adjust medication dosages to achieve optimal thyroid function. 

Interference with testing: 

Certain medications and supplements, such as biotin (found in multivitamins or as a standalone supplement), can affect the accuracy of thyroid blood tests. It is important to inform your health care provider about any supplements or medications you are taking before undergoing thyroid tests. 


Treatment for hypothyroidism typically involves daily oral intake of the thyroid hormone medicine levothyroxine. This medication helps return hormone levels to a normal range, alleviating the symptoms of the condition. 

 Starting treatment 

  • Initial response: You might start feeling better within one to two weeks of beginning the medication. 
  • Longterm management: Treatment with levothyroxine is usually lifelong. Your healthcare provider might adjust your dosage periodically, based on annual checks of your TSH (thyroidstimulating hormone) levels. 

 Dosage adjustment

  • Monitoring: Your TSH levels will be checked 6 to 8 weeks after you start the medication and possibly again six months later to find the correct dosage. 
  • Side effects: Proper dosage is crucial as too much levothyroxine can lead to tiredness, increased appetite, sleep issues, shakiness, and heart palpitations. 

 Special considerations 

  • Brand consistency: Stick to the same brand of medication unless otherwise advised by your healthcare provider, as potency may vary between brands. 
  • Underlying conditions: Patients with coronary artery disease or severe hypothyroidism may start with a lower dose to gradually adapt their heart to increased metabolism. 

 Proper administration of levothyroxine 

  • Timing: Take it on an empty stomach, ideally in the morning, and wait 30 to 60 minutes before eating or taking other medicines. If taken at bedtime, ensure it is at least four hours after the last meal or snack. 
  • Consistency: Do not skip doses or stop taking the medication without guidance, even if you feel better, to prevent the return of symptoms. If a dose is missed, do not double the dose the next day unless advised. 


  • Diet and supplements: Some foods, supplements, and medicines can interfere with levothyroxine absorption. Discuss with your healthcare provider if you consume large amounts of soy, have a highfiber diet, or take supplements containing iron, aluminum hydroxide, or calcium. 

 Subclinical hypothyroidism 

  • Treatment decision: If diagnosed with subclinical hypothyroidism, discuss the benefits of treatment with your healthcare provider. Treatment may not be necessary for mild increases in TSH, but higher levels within the subclinical range might benefit from thyroid hormone therapy to improve symptoms.