Can hypothyroidism cause mood swings?

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December 29, 2025
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Can hypothyroidism cause mood swings?

This article is written by mr.hotsia, a curious traveler who has spent years exploring Thailand, Laos, Vietnam, Cambodia, Myanmar, India and many other Asian countries.

In guesthouses, bus stations and hospital waiting rooms, I often hear people say quietly:

“Some days I feel calm, the next day I am angry and ready to cry.”
“My thyroid is slow. Is this why my mood changes so fast?”
“I do not know if I am stressed, depressed or if it is my hormones.”

Mood swings are not only about personality or willpower.
Your hormones, brain chemistry, sleep, stress and health conditions all play a role.
Hypothyroidism is one of the conditions that can affect mood in some people.

Let us walk through this step by step in simple language.

1. Short answer

The simple answer is:

  • Yes, hypothyroidism can be linked with mood changes and mood swings in some people

  • It may cause:

    • Irritability

    • Feeling unusually sensitive

    • Periods of low mood or depression

    • Emotional ups and downs linked to tiredness and stress

  • But mood swings are usually multi factor. Thyroid is often one piece of the puzzle, not the only cause

Understanding this can change the question from “What is wrong with me?” to “What is my body trying to tell me?”

2. What is hypothyroidism again?

Hypothyroidism means your thyroid gland is underactive and does not produce enough thyroid hormone.

Thyroid hormone helps regulate:

  • Metabolism and energy

  • Brain function

  • Heart rate and blood pressure

  • Body temperature

  • Digestion, skin and hair

  • Many other hormones in your body

Common symptoms include:

  • Tiredness and low energy

  • Feeling cold more than others

  • Weight gain or difficulty losing weight

  • Dry skin and hair thinning

  • Constipation

  • Puffy face or swelling

  • Heavy or irregular periods in some women

Because thyroid hormones affect the brain and nervous system, they can also influence mood and emotions.

3. How can hypothyroidism affect mood?

There are several ways hypothyroidism may contribute to mood swings.

a) Brain chemistry and hormone balance

Your mood is influenced by brain chemicals such as:

  • Serotonin

  • Dopamine

  • Norepinephrine

Thyroid hormones help support normal activity of these systems. When thyroid hormone is low:

  • Brain chemistry may be less stable

  • Signals that support balanced mood may be weaker

This does not mean you are “crazy”. It means the biological background for mood is under extra stress.

b) Fatigue and burnout

Many people with hypothyroidism describe:

  • Constant tiredness

  • Feeling heavy and slow

  • Needing more sleep but still waking unrefreshed

When your body is exhausted:

  • Small problems can feel very big

  • You may be patient in the morning but irritable at night

  • Emotional control becomes harder when energy is low

So some mood swings are not “random”. They follow your energy level and how drained you feel.

c) Physical discomfort and frustration

Hypothyroidism can cause:

  • Weight gain

  • Cold intolerance

  • Joint or muscle aches

  • Slower thinking and brain fog

Living with these daily symptoms can lead to:

  • Frustration

  • Feeling trapped in your own body

  • Sudden waves of sadness or anger when you hit your limit

Over time, this can look like mood swings, but it is also a reaction to living with a long term condition.

d) Impact on sleep

Hypothyroidism may disturb sleep by:

  • Causing discomfort, pain or restlessness

  • Contributing to low mood or anxiety that keeps you awake

Poor sleep alone can cause:

  • Irritability

  • Tearfulness

  • Difficulty handling stress

Put these together and it is easy to see why mood becomes more unstable.

4. Mood swing patterns often seen with hypothyroidism

Not everyone is the same, but some people describe patterns like:

  • Feeling calm in the morning, then more irritable and emotional when tired at night

  • Being unusually sensitive to criticism or small conflicts

  • Switching between:

    • “I feel OK, I can handle life” and

    • “I cannot cope, everything feels too much”

Others report:

  • Periods of clearly low mood or depression

  • A general emotional “flatness” where joy feels hard to access

  • Anxiety or worry that was not present before

These experiences can be confusing, especially if you were previously emotionally stable.

5. Mood swings only hypothyroidism, or could it be other things?

Mood swings are not specific to hypothyroidism. Many other factors can cause or worsen them, for example:

  • Stress at work, money or relationships

  • Depression or anxiety disorders

  • Bipolar disorder

  • Hormonal changes such as:

    • Premenstrual cycle

    • Perimenopause or menopause

    • After childbirth

  • Sleep deprivation

  • Alcohol or drug use

  • Certain medications

  • Other medical conditions such as anemia, chronic pain, blood sugar problems

Hypothyroidism can be part of this picture, but it is rarely the only answer. This is why careful evaluation is important.

6. How do I know if my mood swings might be thyroid related?

You cannot know for sure without tests, but some clues suggest thyroid might be involved:

  • Mood swings come together with several physical signs of hypothyroidism:

    • Feeling cold often

    • Unusual weight gain

    • Dry skin and hair loss

    • Constipation

    • Puffy face or swelling

    • Heavy or irregular periods

  • You have a personal or family history of thyroid disease or autoimmune conditions

  • Blood tests in the past have shown borderline or abnormal thyroid levels

  • Mood changes started around the same time as other thyroid like symptoms

In this case, it is reasonable to ask your doctor to check your thyroid as part of a wider mood evaluation.

7. If I treat my hypothyroidism, will my mood swings disappear?

For many people:

  • Treating hypothyroidism properly and bringing thyroid hormones into a healthy range can:

    • Improve energy

    • Support clearer thinking

    • Reduce feelings of depression and anxiety

    • Make mood more stable

However:

  • Mood may not improve overnight

  • It can take weeks to months after thyroid levels normalize

  • If there are other causes of mood problems (stress, past trauma, separate mental health conditions), these may need their own treatment

So correcting thyroid levels is often an important foundation, but not always the whole solution.

8. When should I see a doctor urgently about mood changes?

You should seek urgent medical or mental health help if:

  • You have thoughts of harming yourself

  • You feel life is not worth living

  • You think about suicide or making a plan

  • You cannot control your actions when angry and may hurt others

These situations are emergencies for your emotional health, regardless of the cause.

For less urgent but still important concerns, you should see a doctor soon if:

  • Mood swings are frequent or intense

  • They affect your work, relationships or daily life

  • You have several physical symptoms of hypothyroidism at the same time

  • You feel depressed or anxious most days for more than a couple of weeks

9. What can I do next if I suspect hypothyroidism is affecting my mood?

You do not have to fix everything alone. You can take small steps.

Step 1: Write down your symptoms

Include:

  • Mood changes: irritability, sadness, anxiety, sudden tears, anger

  • Physical symptoms: cold, weight, skin, hair, bowels, periods, sleep

  • How long they have been happening

  • Any family thyroid history or past thyroid tests

Step 2: See a doctor

Ask clearly:

“I am having mood swings and I also have symptoms that sound like an underactive thyroid. Can we check my thyroid function and also talk about other possible causes of my mood changes?”

Your doctor may:

  • Order thyroid blood tests

  • Look for other physical causes like anemia, vitamin deficiencies or blood sugar issues

  • Ask about depression, anxiety and life stress

  • Suggest counseling, lifestyle changes or medication if needed

Step 3: Support your brain and hormones with small habits

These do not replace medical care, but may support more stable mood:

  • Try to keep a regular sleep schedule

  • Eat simple, balanced meals and avoid extreme dieting

  • Reduce heavy alcohol use if present

  • Include gentle physical activity, like walking, most days

  • Talk to someone you trust about how you feel

Frequently Asked Questions: Can hypothyroidism cause mood swings?

1. Can an underactive thyroid really cause mood swings?
Yes. Hypothyroidism can be linked with irritability, low mood, emotional sensitivity and mood swings in some people, especially when thyroid levels are far from normal.

2. Is every mood swing caused by thyroid problems?
No. Many things can affect mood, including stress, mental health conditions, hormones, sleep problems and medications. Thyroid issues are only one possible cause.

3. Can hypothyroidism cause depression and anxiety too?
Yes. Hypothyroidism is known to be associated with symptoms of depression and, in some people, anxiety. Treating the thyroid may help, but sometimes additional mental health support is needed.

4. If my thyroid tests are normal, does that mean my mood swings are “all in my head”?
No. Normal thyroid tests mean your thyroid is less likely to be the cause, but your feelings are still real. Other physical, emotional or social causes should be considered.

5. How long after starting thyroid treatment will my mood improve?
Some people feel better within a few weeks when thyroid levels begin to normalize. For others, it can take several months. If mood problems continue, talk to your doctor about other supports.

6. Can I just take thyroid medicine to fix my mood?
Thyroid medication should only be taken if tests show you need it and a doctor prescribes it. Taking thyroid hormone without a real deficiency can be harmful and will not reliably fix mood problems.

7. Are mood swings from hypothyroidism permanent?
Not necessarily. When thyroid levels are corrected and other contributing factors are addressed, many people experience more stable mood over time.

8. Can stress make thyroid related mood swings worse?
Yes. Stress can make both thyroid symptoms and mood changes feel more intense. Managing stress with healthy coping strategies may help reduce emotional ups and downs.

9. Should I see a psychiatrist or just an endocrinologist?
For mood swings plus thyroid symptoms, it often helps to see a general doctor or endocrinologist for thyroid evaluation and, if needed, a mental health professional for emotional support. They can work together.

10. What is one practical step I can take this week?
You can:

  • Write a short summary of your mood changes and physical symptoms,

  • Then bring it to your doctor and say:

“My mood has been very up and down, and I also have signs of a possible slow thyroid. I want to understand if my thyroid is involved and what we can do to support both my physical health and my mental health.”

Turning confusion into a clear, honest conversation is often the first step toward feeling more stable, understood and in control.

Mr.Hotsia

I’m Mr.Hotsia, sharing 30 years of travel experiences with readers worldwide. This review is based on my personal journey and what I’ve learned along the way. Learn more