Hashimoto’s Symptoms and How It Is Diagnosed

By Anna Curran, RN, BSN, PHN · Last reviewed October 2026

Hashimoto’s symptoms often start so slowly that you may not notice them for years. The most common ones are tiredness, feeling cold, constipation, dry skin, weight gain and a swollen neck. Doctors confirm the diagnosis with blood tests, mainly TSH, free T4 and thyroid antibodies.

Because these symptoms can look like so many other things, it is easy to brush them off. Here is what to watch for, how testing works and what your results may mean.

Why Hashimoto’s Symptoms Are Easy to Miss

Hashimoto’s disease is an autoimmune condition. Your immune system slowly damages your thyroid, the gland in your neck that helps control your energy and metabolism.

The damage usually happens over many years. Early on, your thyroid can often keep up, so you may feel fine. Many people have no symptoms at first, according to NIDDK and the American Thyroid Association.

Symptoms show up when the thyroid can no longer make enough hormone. That is called hypothyroidism. Even then, the changes are gradual. You may blame them on stress, poor sleep or getting older.

Common Hashimoto’s Symptoms

Most Hashimoto’s symptoms come from low thyroid hormone. Your body slows down in many small ways. According to Mayo Clinic, Cleveland Clinic and NIDDK, symptoms can include:

Energy and mood

Fatigue and feeling sluggish
Sleeping more than usual
Low mood or depression
Trouble with memory or focus

Body temperature and skin

Feeling cold when others are comfortable
Dry skin
Brittle nails
Hair loss or thinning hair
A puffy face or puffy eyes

Muscles, joints and digestion

Muscle aches, tenderness and stiffness
Muscle weakness
Joint pain and stiffness
Constipation

Weight, heart and hormones

Weight gain you cannot explain
A slow heart rate
Heavy or irregular periods
Lower sex drive
Trouble getting pregnant

Neck changes

A swollen thyroid, called a goiter
A feeling of fullness or pressure in your throat
Trouble swallowing if the goiter is large

A goiter may be the first or only sign early on. It is usually not painful.

Rarely, Hashimoto’s can cause short-lived symptoms of an overactive thyroid early in the disease. These include a racing heart, feeling shaky or feeling nervous.

When to See Your Doctor

You do not need to have every symptom. Even a few that last for weeks are worth a visit. Mayo Clinic advises seeing your provider soon for a timely, accurate diagnosis, since these symptoms overlap with many other conditions.

Make an appointment if you:

Feel tired all the time, even with good sleep
Notice a swelling at the front of your neck
Have dry skin, hair loss and feel cold often
Have heavy or irregular periods that are new for you
Have a family history of thyroid disease and new symptoms
Have another autoimmune disease, such as type 1 diabetes or celiac disease, and notice changes

Call 911 or go to the ER if you have trouble breathing, a swollen neck that makes it hard to breathe or swallow, extreme sleepiness or confusion, a very low body temperature or a very slow heartbeat.

How Hashimoto’s Is Diagnosed

Diagnosis usually starts with a talk about your symptoms and family history. Your doctor will feel your neck to check the size of your thyroid. Then blood tests give the answers.

TSH test

TSH stands for thyroid-stimulating hormone. It is made by the pituitary gland in your brain. TSH tells your thyroid how much hormone to make.

When your thyroid slows down, your brain sends out more TSH to push it along. So a high TSH most often means an underactive thyroid.

MedlinePlus lists a normal TSH range of 0.4 to 4.8 microunits per milliliter (µU/mL). Ranges vary a little between labs, and some labs use a higher upper limit for older adults. Ask your provider what your own result means.

TSH also changes during the day. MedlinePlus notes the test is best done early in the morning.

Free T4 test

T4 is the main hormone your thyroid makes. “Free” T4 is the part that is active and ready for your body to use. Many doctors prefer free T4 because pregnancy, birth control pills and some illnesses can change total T4 without any thyroid problem.

A low free T4 with a high TSH points to hypothyroidism.

TPO antibody test

This test looks for thyroid peroxidase (TPO) antibodies. These are made when your immune system targets your thyroid. Most people with Hashimoto’s have them, according to NIDDK and Mayo Clinic.

Your doctor may also test for thyroglobulin antibodies. A positive antibody test helps show that Hashimoto’s, an autoimmune cause, is behind thyroid changes.

Thyroid ultrasound

An ultrasound uses sound waves to make a picture of your thyroid. It is painless and is done by moving a small wand over your neck.

You may not need one. NIDDK says an ultrasound is usually not needed to confirm Hashimoto’s. Your doctor may order it if:

Your blood tests suggest Hashimoto’s but no antibodies are found
Your thyroid feels enlarged
Your doctor wants to check for lumps, called nodules

The American Thyroid Association notes an ultrasound can show signs of inflammation even when hormone levels are still normal.

What Your Results May Mean

Thyroid results can be confusing. This table shows common patterns. Your doctor will look at your whole picture, not just one number.

TSH	Free T4	TPO antibodies	What it may mean
Normal	Normal	Positive	Hashimoto’s without hypothyroidism; usually watched over time
Slightly high	Normal	Positive or negative	Mild (subclinical) hypothyroidism
High	Low	Positive	Hypothyroidism caused by Hashimoto’s

Antibodies With a Normal TSH

Many people are surprised to learn they have TPO antibodies but a normal TSH. What does that mean?

It means your immune system is targeting your thyroid, but your thyroid is still keeping up. Hashimoto’s tends to move slowly, so this stage can last a long time.

Here is what the American Thyroid Association says about this stage:

You do not need thyroid hormone treatment when your TSH and free T4 are normal.
You do not need repeat antibody tests. The antibody result does not need to be tracked.
Your TSH should be checked over time, since low hormone levels may develop later.

Cleveland Clinic adds that some people test positive for antibodies but never get thyroid disease. Others may develop hypothyroidism later in life. Regular checkups help you catch changes early.

What about mild hypothyroidism?

Sometimes TSH is a little high, but free T4 is still normal. This is called subclinical, or mild, hypothyroidism. The ATA says this may or may not need medicine right away. Your doctor may check your TSH once or twice a year to see if it changes.

Things That Can Affect Your Test Results

A few common things can throw off thyroid tests:

Biotin. This B vitamin is in many hair, skin and nail supplements. MedlinePlus notes it can affect TSH results. Tell your provider before testing if you take it.
Certain medicines. Steroids like prednisone, lithium, amiodarone and some others can change thyroid results.
Pregnancy and birth control pills. These can change total T4 levels.
Recent illness. Being very sick can change thyroid levels for a while.

Do not stop any medicine or supplement before a test unless your provider tells you to.

Frequently Asked Questions

Can you have Hashimoto’s with normal thyroid levels?

Yes. Many people have positive TPO antibodies while their TSH and free T4 are still normal. This usually does not need treatment, but your doctor will likely check your TSH over time.

What are the first signs of Hashimoto’s?

Often there are none. When signs do appear, a swollen neck, tiredness, feeling cold and dry skin are common early clues. Symptoms usually build slowly.

Do I need an ultrasound to diagnose Hashimoto’s?

Usually not. Blood tests are enough for most people. Your doctor may order an ultrasound if antibodies are negative, your thyroid feels enlarged or there may be a nodule.

Can Hashimoto’s symptoms come and go?

Symptoms can seem to change from day to day, since tiredness and mood have many causes. If symptoms come back after you start treatment, your dose may need adjusting. Tell your doctor so your TSH can be checked.

The Bottom Line

Hashimoto’s symptoms build slowly and can be easy to miss, so a blood test is the only way to know for sure. TSH, free T4 and TPO antibody tests are the main tools for diagnosis, and most people do not need an ultrasound. Positive antibodies with a normal TSH usually mean watching and waiting, not medicine. If you have symptoms or a family history, ask your provider whether thyroid testing is right for you.