Thyroid Function Test 

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📌 What is the Thyroid?

Your thyroid is a small, butterfly-shaped gland in your neck. Even though it’s small, it controls many big things in your body, like:

• Your energy

• How fast you burn calories

• How warm or cold you feel

• Your weight

• Your mood

• Your heartbeat

To do all this, your thyroid makes two important hormones:

• T3 (Triiodothyronine)

• T4 (Thyroxine)

These hormones help your body’s systems work at the right speed.

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🔄 How Does the Body Control the Thyroid?

Your brain helps control your thyroid through a hormone called TSH (Thyroid Stimulating Hormone). TSH is made by the pituitary gland in your brain and tells your thyroid when to work harder or slow down.

When your thyroid doesn’t work properly, your T3 and T4 levels may become too high or too low — and that can affect how you feel.

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🧪 What’s in a Thyroid Function Test?

A thyroid function test usually includes 3 main parts:

TestWhat It Tells Us

TSHIs your brain asking your thyroid to speed up or slow down?

Free T4 (FT4)How much hormone your thyroid is making

Free T3 (FT3)How much active hormone your body can use

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🧊 Signs Your Thyroid is Too Slow (Hypothyroidism)

• Feeling tired or sleepy

• Gaining weight

• Feeling cold all the time

• Constipation

• Depression or low mood

• Dry skin and hair loss

• Slow heartbeat

• Heavy or irregular periods

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🔥 Signs Your Thyroid is Too Fast (Hyperthyroidism)

• Feeling nervous or anxious

• Losing weight without trying

• Feeling hot or sweaty

• Fast heartbeat or palpitations

• Trouble sleeping

• Shaky hands

• More frequent bowel movements

• Light or irregular periods

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​​​​​​​​​💊 What’s the Treatment?

• Hypothyroidism (Too Slow): Take a daily thyroid hormone pill (Levothyroxine) to replace what your body isn’t making.

• Hyperthyroidism (Too Fast): Treatments may include medications, radioactive iodine, or surgery, depending on the cause.