The reasons for this are complex.
TSH test levels can vary due to causes as simple as medication you take or the time of day.
Other concerns may require treatment, typically withlevothyroxine.
Verywell / Shideh Ghandeharizadeh
This article explains why it’s possible to have hypothyroidism with a normal TSH level.
These symptoms can include:
There are two main types of conditionsprimary and secondary hypothyroidismthat may be at play.
Endocrine Function
Other hormones work with TSH to help regulate processes in your body.
Get our printable guide for your next healthcare provider’s appointment to help you ask the right questions.
For example, thepituitary glandis where TSH is produced.
TSH isn’t actually a thyroid hormone.
It’s produced in the pituitary gland and acts on the thyroid.
TSH levels tell only a part of the story in terms of thyroid function, symptoms, and treatment.
Your TSH levels can be lower during the first trimester.
Or, high estrogen levels may increase thyroid hormone levels.
While hyperthyroidism (as with Graves' disease) is a concern, so is hypothyroidism.
Low levels of thyroid in a pregnant person also can affect thyroid and brain development in the fetus.
Treatment isn’t always necessary but a healthcare provider may prescribe levothyroxine (LT4).
Medication
Certain medications, including corticosteroids likeprednisone, can lead to low TSH levels.
Some studies suggest vitamin D levels also may have an impact.
So can alternative treatments for thyroid conditions for which there is no evidence of benefit.
Cancer Treatments
Hypothyroidism can be due to radiation therapy forhead and neck cancers.
This appeared to be more common in younger people and those assigned female at birth.
But it doesn’t always happen.
This may mean that people still have symptoms despite “normal” TSH.
Thus, their hypothyroidism can be missed by healthcare providers.
This may mean you are less prone to symptoms.
The majority of people first starting treatment will be prescribed the Synthroid brand.
Other available brands include Levoxyl, Levothroid, and Unithroid.
T3 hormones can also interfere with T4 blood test results and complicate the monitoring of your disease.
All of these things are true but to a degree.
The combination of Cytomel and levothyroxine may improve symptoms without any additional side effectscompared to levothyroxine alone.
Keep in mind that medication may not be needed.
Other Conditions Causing Hypothyroidism Symptoms
Several conditions can cause symptoms that are similar to those of hypothyroidism.
It can help to discuss these options if you have normal TSH levels but still experience hypothyroidism symptoms.
The reasons for your symptoms may vary, depending on the underlying cause.
Medication may not always be necessary but LT4 and other treatments may bring symptom relief.
Consider alternative options, too, when talking with your endocrinologist.
If you are uncertain about the care you are receiving, do not hesitate toseek a second opinion.
Get our printable guide for your next healthcare provider’s appointment to help you ask the right questions.
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