Learn about thyroid problem causes and symptoms

Learn about thyroid problem causes and symptoms

started waking up exhausted after 9 hours of sleep, gaining weight while eating less, and feeling like my brain was stuck in airplane mode. That’s when I finally got curious… and a bit desperate.

A simple blood test later, my doctor told me: “Your TSH is high. You’ve got hypothyroidism.” That moment sent me down a deep rabbit hole of thyroid research, late-night PubMed searches, and yes, some panicked Googling.

If you’ve been wondering whether your own weird mix of symptoms might be thyroid-related, you’re absolutely not alone. Let’s unpack what I wish I knew earlier.

What your thyroid actually does (and why it matters so much)

Your thyroid is a small, butterfly-shaped gland at the front of your neck. Tiny, but it’s the boss of your metabolism.

It mainly produces two hormones:

• T4 (thyroxine) – the storage form
• T3 (triiodothyronine) – the active form your cells actually use

Your brain controls this via TSH (thyroid-stimulating hormone) from the pituitary gland. Think of it like a thermostat: when thyroid hormones are low, TSH goes up, yelling at the thyroid to work harder.

In my lab tests, my TSH was elevated, and my free T4 was at the low end of normal. Classic pattern for hypothyroidism.

When thyroid hormones are off, it can affect:

• Energy and metabolism
• Mood and mental clarity
• Heart rate and blood pressure
• Menstrual cycles and fertility
• Body temperature and even your skin and hair

So when people say they “don’t feel like themselves,” and it turns out to be thyroid-related, it makes sense.

Common thyroid problems: the big three

1. Hypothyroidism (underactive thyroid)

This is what I was diagnosed with. In hypothyroidism, your thyroid doesn’t produce enough hormones.

The most common cause in countries with sufficient iodine is Hashimoto’s thyroiditis, an autoimmune disease where your immune system gradually attacks your thyroid. The American Thyroid Association estimates that up to 5% of the U.S. population has hypothyroidism, with women affected far more often.

Other causes include:

• Thyroid surgery or radioactive iodine treatment
• Certain medications (like amiodarone or lithium)
• Severe iodine deficiency (still an issue in some regions globally)
• Postpartum thyroiditis (happens after pregnancy)

2. Hyperthyroidism (overactive thyroid)

Here, your thyroid is cranked up too high. The most common cause is Graves’ disease, another autoimmune condition. In this case, antibodies stimulate the thyroid instead of attacking it.

Other causes:

• Toxic multinodular goiter (multiple overactive nodules)
• A single "hot" nodule producing excess hormone
• Thyroiditis (temporary inflammation)

3. Thyroid nodules and cancer

Thyroid nodules are super common — most are benign. I had a small one show up on an ultrasound once, and the radiologist casually said, “We see these all the time.” Not exactly calming, but statistically true.

A very small percentage are cancerous. Thyroid cancer is usually slow-growing and treatable, but it still needs proper evaluation.

Thyroid problem symptoms: what I noticed vs what the textbooks say

When my thyroid started misbehaving, my symptoms were subtle and easy to blame on stress. Looking back, they were textbook.

Hypothyroidism symptoms (underactive)

Here’s what I experienced first:

• Crushing fatigue – the kind where walking up stairs feels like a workout
• Weight gain despite no big change in diet
• Brain fog – losing words mid-sentence, rereading the same paragraph

Common hypothyroid symptoms include:

• Constant tiredness, low energy
• Feeling cold all the time (cold hands and feet especially)
• Unexplained weight gain or difficulty losing weight
• Dry skin, hair loss, thinning outer eyebrows
• Constipation
• Heavy or irregular periods
• Slowed heart rate
• Depression, low mood, or feeling “flat”

I remember sitting in my car one winter, heater on full blast, still shivering, and thinking: “Something is off. This cannot just be being ‘tired.’”

Hyperthyroidism symptoms (overactive)

On the flip side, hyperthyroidism often looks like someone’s body is stuck on fast-forward:

• Unintentional weight loss
• Rapid or irregular heartbeat (palpitations)
• Nervousness, anxiety, irritability
• Heat intolerance, excessive sweating
• Tremors (shaky hands)
• Frequent bowel movements or diarrhea
• Trouble sleeping
• Lighter or irregular periods

I haven’t personally had hyperthyroidism, but two friends with Graves’ disease both described it similarly: “Like I drank six cups of coffee and never came down.”

Symptoms that overlap or confuse everyone

This is where things get tricky.

Both hypo and hyperthyroidism can cause:

• Mood changes (anxiety or depression)
• Sleep disturbances
• Menstrual and fertility issues
• Hair and skin changes

And those symptoms can just as easily be blamed on stress, burnout, aging, or "being busy." That’s why blood tests matter so much.

What actually causes thyroid problems?

Here’s what I found when I nerded out on the research and grilled my endocrinologist.

1. Autoimmune disease

For many of us, the root cause is autoimmune:

• Hashimoto’s thyroiditis → usually causes hypothyroidism
• Graves’ disease → usually causes hyperthyroidism

In both, your immune system starts targeting parts of your thyroid:

• With Hashimoto’s, it gradually damages the gland.
• With Graves’, antibodies (TSI – thyroid-stimulating immunoglobulins) keep telling the thyroid to make more hormone.

Autoimmune tendencies can run in families. In my case, a relative had vitiligo and another had rheumatoid arthritis — big hint.

2. Iodine imbalance

The thyroid needs iodine to produce hormones:

• Too little iodine → hypothyroidism and goiter (enlarged thyroid)
• Too much iodine → can also trigger thyroid dysfunction in some people

In many countries, iodized salt reduced severe iodine deficiency, but it’s still a practical issue globally, especially in parts of Africa and Asia.

3. Medications and treatments

Certain drugs can interfere with the thyroid:

• Amiodarone (heart medication)
• Lithium (used in some mood disorders)
• Some cancer therapies (immune checkpoint inhibitors)

Medical treatments like radioactive iodine or thyroid surgery can also reduce thyroid function intentionally or as a side effect.

4. Pregnancy and postpartum changes

Pregnancy puts your thyroid under extra pressure. Some women develop postpartum thyroiditis, which can cause a rollercoaster:

• First a phase of hyperthyroidism
• Then a drop into hypothyroidism

I’ve seen friends write off extreme fatigue and mood swings after birth as just “new mom life,” only to later find out their thyroid was all over the place.

5. Genetics and environment (the messy middle)

There’s no single “thyroid gene,” but there are genetic patterns. Environmental triggers may include:

• Smoking (especially relevant in Graves’ disease and eye symptoms)
• Severe stress or illness (can unmask underlying issues)
• Possible links with certain environmental toxins (research is ongoing)

But it’s rarely one thing. It’s more like a perfect storm: genetics + environment + time.

How thyroid problems are diagnosed (what actually happens)

When I finally went for testing, here’s what my doctor ordered:

1. TSH (Thyroid Stimulating Hormone) – the usual first-line test
2. Free T4 (and sometimes Free T3) – to see actual hormone levels
3. Thyroid antibodies – like TPO antibodies, to check for Hashimoto’s or Graves’
4. Ultrasound if there’s a lump or enlargement

A classic pattern for common conditions:

• High TSH + low/free low-normal T4 → hypothyroidism
• Low TSH + high T4/T3 → hyperthyroidism

My TSH came back at over 7 mIU/L, with elevated anti-TPO antibodies. That sealed the diagnosis: Hashimoto’s hypothyroidism.

What helped me: treatments and expectations

Standard treatment (what most guidelines recommend)

For hypothyroidism, the gold standard is levothyroxine (synthetic T4). I take it daily, first thing in the morning.

Pros, in my experience:

• It’s well-studied and widely used
• Doses can be adjusted precisely
• My energy and mood realistically improved within a few weeks

Cons and realities:

• Finding the right dose can take time and a few blood tests
• You have to be consistent about how you take it (usually on an empty stomach)
• It doesn’t fix everything overnight — especially if you’ve felt unwell for years

For hyperthyroidism, common treatments include:

• Antithyroid drugs (like methimazole)
• Radioactive iodine to shrink the gland
• Surgery in specific situations

Each has pros and cons, and this is where a good endocrinologist is worth gold.

Lifestyle: helpful, but not magic

I experimented a lot: diet tweaks, stress management, sleep hygiene.

What genuinely helped me:

• Getting enough protein (stabilized energy a bit)
• Prioritizing sleep and keeping a regular schedule
• Gentle movement instead of punishing workouts when exhausted

What didn’t cure my thyroid:

• Cutting out gluten (for me personally, no change)
• Random supplements recommended by the internet

Lifestyle changes can support your overall health and may help you feel better, but they do not replace proper medical treatment if your hormones are objectively off.

When to actually get checked

Based on my experience and what major guidelines suggest, it’s worth asking your doctor for thyroid tests if you notice a cluster of these:

• Constant fatigue that sleep doesn’t fix
• Unexplained weight changes
• Hair loss, dry skin, feeling cold or overheated
• Heart palpitations, tremors, or anxiety without a clear trigger
• Major menstrual changes or fertility struggles
• Family history of thyroid or autoimmune disease

One test I wish I’d done a year earlier: a simple TSH blood test.

The bottom line: you’re not “just tired” or “just stressed”

When my numbers finally came back, I remember feeling oddly relieved. I wasn’t lazy. I wasn’t making it up. My thyroid genuinely needed help.

Thyroid problems are incredibly common, often underdiagnosed, and very treatable once identified. If your body’s been sending you weird mixed signals — from your weight to your mood to your heart rate — it’s worth listening and getting checked.

And if your labs already show thyroid issues, you’re not stuck. With the right mix of medical care, realistic expectations, and supportive habits, you really can feel like yourself again — or sometimes, better than you have in years.

Sources

• American Thyroid Association – Thyroid Function Tests - Clear overview of standard thyroid blood tests and what they mean.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – Hypothyroidism - U.S. government resource on causes, symptoms, and treatment of hypothyroidism.
• Mayo Clinic – Hyperthyroidism - Detailed explanation of hyperthyroidism, including Graves’ disease and treatment options.
• Cleveland Clinic – Hashimoto’s Disease - In-depth look at Hashimoto’s thyroiditis, diagnosis, and management.
• BBC Future – The misunderstood thyroid - Accessible overview of how the thyroid works and why disorders are often missed.