Published: 29 Mar 2025

Fatigue, weight changes, and alterations in TSH (thyroid-stimulating hormone) and Free T4 (thyroxine) levels are often interconnected and can indicate a thyroid disorder.
Here's a breakdown of how these factors relate: �

Thyroid Hormones and Their Role:

Thyroid gland:
This gland produces hormones, primarily T4 and T3 (triiodothyronine), that regulate metabolism. �
TSH:
Produced by the pituitary gland, TSH stimulates the thyroid to produce T4 and T3. �
TSH levels are often used as a primary screening tool for thyroid function. �
Free T4:
This is the unbound, active form of thyroxine in the bloodstream. It provides a more accurate assessment of thyroid function than total T4. �
Relationship Between Symptoms and Thyroid Levels:

Hypothyroidism (Underactive Thyroid):
Symptoms: Fatigue, weight gain, cold intolerance, dry skin, constipation, and depression. �
Typical lab results: High TSH and low Free T4. �
Hyperthyroidism (Overactive Thyroid):
Symptoms: Fatigue, weight loss, rapid heart rate, anxiety, heat intolerance, and tremors.
Typical lab results: Low TSH and high Free T4.
Key Considerations:

Fatigue:
This is a common symptom in both hypothyroidism and hyperthyroidism, though the underlying mechanisms differ. �
Weight Changes:
Weight gain is more characteristic of hypothyroidism, while weight loss is more common in hyperthyroidism. However, atypical presentations can occur.
TSH and Free T4 Testing:
These blood tests are essential for diagnosing thyroid disorders and monitoring treatment. �
It's important to interpret these results in conjunction with a patient's symptoms.
Other Factors:
It is also worth noting that many other medical issues can cause these symtoms. So a doctors consultation is very important.
In summary:

If you are experiencing fatigue and unexplained weight changes, it is important to have your TSH and Free T4 levels checked. This will help your doctor determine if a thyroid disorder is contributing to your symptoms.