🐢 Hypothyroidism Explained

This page explains the symptoms and causes of hypothyroidism, how it is diagnosed with blood tests, and the treatment options used to restore normal thyroid hormone levels.

Hypothyroidism means your thyroid is not making enough thyroid hormone.

It is the most common thyroid problem in adults.

🔎 What Is Hypothyroidism? 

“Hypo” means low or underactive.

So hypothyroidism simply means:

➡ Your thyroid is working too slowly

When this happens, your body’s systems slow down.

🧠 What Happens in the Body 

With low thyroid hormone:

• Metabolism slows
  
  

• Energy drops
  
  

• Body temperature regulation changes
  
  

• Digestion slows
  
  

• Heart rate may slow
  
  

• Brain function can feel foggy
  
  

Because thyroid hormones affect almost everything, symptoms can be very wide-ranging.

📌 Most Common Causes 

The most common causes of hypothyroidism are:

1) Hashimoto’s Disease

• An autoimmune condition
  
  

• The immune system attacks the thyroid
  
  

• Most common cause in the U.S.
  
  

2) Thyroid Surgery

• If part or all of the thyroid is removed
  
  

3) Radioactive Iodine Treatment

• Often used to treat hyperthyroidism
  
  

4) Iodine Deficiency

• Rare in the U.S. but common worldwide
  
  

5) Certain Medications

• Some medicines can affect thyroid function

😴 Common Symptoms of Hypothyroidism 

Symptoms often develop slowly over time.

You may notice:

• Constant tiredness
  
  

• Low energy
  
  

• Weight gain
  
  

• Feeling cold easily
  
  

• Dry skin
  
  

• Hair thinning or hair loss
  
  

• Constipation
  
  

• Depression or low mood
  
  

• Brain fog or poor concentration
  
  

• Puffy face
  
  

• Brittle nails
  
  

• Heavy or irregular periods
  
  

• Slower heart rate
  
  

Many people describe feeling like they are moving through life in slow motion.

❗ Symptoms Can Be Subtle 

Early on, symptoms may be mild and easy to miss.

Hypothyroidism is often mistaken for:

• Stress
  
  

• Aging
  
  

• Depression
  
  

• Poor sleep
  
  

• Being “too busy”
  
  

That’s why blood tests are so important.

🧪 How Hypothyroidism Is Diagnosed 

Diagnosis is based mainly on blood tests.

The Typical Pattern Is:

• High TSH
  
  

• Low Free T4
  
  

This combination confirms hypothyroidism.

Other Tests That May Be Checked

• Thyroid antibodies (TPO)
  
  

• Free T3
  
  

• Thyroid ultrasound (sometimes)

🧩 What “Subclinical Hypothyroidism” Means 

Sometimes tests show:

• High TSH
  
  

• Normal Free T4
  
  

This is called subclinical hypothyroidism.

It means the thyroid is starting to struggle but hasn’t fully failed yet.

Doctors decide about treatment based on:

• Symptoms
  
  

• TSH level
  
  

• Age
  
  

• Other health conditions

💊 Treatment for Hypothyroidism 

The main treatment is:

➡ Thyroid hormone replacement

The most common medication is:

• Levothyroxine (synthetic T4)

How Treatment Works

• You take one pill daily
  
  

• It replaces the hormone your body isn’t making
  
  

• TSH levels are monitored
  
  

• Dose is adjusted over time
  
  

Most people feel much better once levels are corrected.

🕒 How Long Treatment Takes 

• It can take 4–8 weeks to feel improvement
  
  

• Dose adjustments happen gradually
  
  

• Most people need lifelong treatment
  
  

Once stable, thyroid checks are usually every 6–12 months.

🌱 Can Lifestyle Help? 

Lifestyle changes cannot cure hypothyroidism, but they can help you feel better:

• Eating balanced meals
  
  

• Regular exercise
  
  

• Good sleep habits
  
  

• Managing stress
  
  

• Taking medication exactly as prescribed

❓ Is Hypothyroidism Curable? 

In most cases:

• Hypothyroidism is treatable, not curable
  
  

• Especially when caused by Hashimoto’s
  
  

• Medication usually controls it very well
  
  

Some temporary forms (like thyroiditis) may improve on their own.

🧭 What Usually Happens Next 

If you are diagnosed with hypothyroidism, the usual plan is:

1. Start thyroid medication
   
   

2. Recheck TSH in 6–8 weeks
   
   

3. Adjust dose if needed
   
   

4. Continue monitoring long term
   
   

With proper treatment, most people live completely normal lives.

🔑 Big Takeaways 

Hypothyroidism = underactive thyroid

It slows many body systems

Diagnosis is mainly based on TSH and Free T4

Treatment is simple and effective

Most people feel much better with medication

Coming Up Next 

The next page will cover the opposite problem:

➡ Hyperthyroidism Explained (Overactive Thyroid)