in pictures and a few words
What it is and why it matters
Tiredness and low energy can come both from a shortage of thyroid hormones and from burnout. You can’t tell them apart by how you feel alone.
- The good news: a simple blood test checks the thyroid
- Serious diseases are rare among the causes of tiredness
- Burnout is not a lab diagnosis
When thyroid hormones run short
The most common complaints are tiredness and sluggishness. Other signs are often present too.
- Feeling cold: a person is chilly where others are comfortable
- Weight gain, constipation, a change in voice
- Dry skin and hair loss — more often in people with the condition than in healthy people
Honestly. No single sign is reliable on its own. Even a slight suspicion is a reason to get tested.
A blood test checks the thyroid
The thyroid is checked by the hormone that controls it. For most people, this is the best first test.
- If this hormone is high, the doctor adds a test for the thyroid’s own main hormone
- With the two tests together, the doctor sees whether the hormone shortage is clear-cut or mild
- Normal ranges depend on the laboratory
Honestly. The test answers whether the thyroid is all right. Burnout is not a lab diagnosis.
What burnout is
Burnout is not a disease but the result of long-term stress at work that hasn’t been managed. A question to ask yourself: is the tiredness linked mainly to work?
- Exhaustion
- Mental distance from work, or cynicism about it
- A feeling of being ineffective
Honestly. Burnout is noticeably linked to depression, but the authors of a large review considered them different, though partly overlapping, conditions.
Burnout can be reduced
Burnout can be reduced: both personal measures and changes in how work is organized helped.
- Measures aimed at the person themselves
- Measures at the level of work and how it is organized
Tested in people. This was tested in doctors: after measures against burnout, its rate went down.
Cortisol: what it can and can’t do
Cortisol is a hormone of the adrenal glands. A blood test for it serves another purpose: not to miss weak function of the adrenal glands themselves.
- Blood is taken in the morning, together with a test for the hormone that controls the adrenal glands
- It is checked when there are signs of weak adrenal function
- Saliva cortisol curves do not diagnose burnout
Honestly. In studies of cortisol in tiredness, the results almost always contradicted each other, and “adrenal fatigue” as a disease has not been confirmed.
What else to check
With persistent tiredness, the doctor decides what else to test based on your complaints and an examination.
- Iron: iron stores together with a test for inflammation, often a complete blood count
- Blood sugar — so as not to miss diabetes; vitamins — when indicated
- Mood: depression is a common finding with tiredness; the doctor may give you a short questionnaire
Tested in people. In menstruating women without anemia whose test showed low iron, iron by mouth reduced tiredness more than a dummy pill; it had no significant effect on mood.
It can be both
A shortage of thyroid hormones doesn’t protect against burnout, and burnout doesn’t rule out thyroid disease.
- Even when test results on treatment are normal, a noticeable share of people still have complaints
- Then it’s worth checking other causes too, including stress at work and depression
- A slightly raised hormone on a test doesn’t always explain tiredness
Honestly. With a mild shortage in non-pregnant adults, thyroid hormone tablets improved the test results but showed no improvement in how people felt.
Who should see a doctor first
In these cases, don’t put it off and don’t decide on your own.
- You have thoughts that you don’t want to live — seek help right away, without waiting for tests
- Tiredness, persistent unexplained nausea and low blood pressure — see a doctor without delay
- You already take thyroid hormone and the tiredness doesn’t go away — don’t change the dose yourself
Important. Discuss the dose and other causes of tiredness with your doctor. Don’t start thyroid hormones “for tiredness” without a test.
In one sentence
Tiredness can come both from a shortage of thyroid hormones and from burnout, and sometimes from both at once. A blood test checks the thyroid; burnout is not a lab diagnosis.
Key points
Why they are easy to confuse
Fatigue and low energy occur both with a shortage of thyroid hormones (hypothyroidism) and with burnout. The most common complaints in hypothyroidism are fatigue and lethargy (Chaker L Lancet 2017. PMID 28336049[5]). Burnout is described as emotional exhaustion, cynicism and a feeling that one’s own accomplishments have declined; it shares a loss of interest and difficulty concentrating with depression (Koutsimani P Front Psychol 2019. PMID 30918490[6]).
So these conditions cannot be told apart by how you feel alone. A blood test shows whether you have hypothyroidism; burnout is not determined by a lab test.
Signs of hypothyroidism
Besides fatigue, hypothyroidism often brings feeling cold (a person is chilly where others are comfortable), weight gain, constipation, voice changes and dry skin (Chaker L Lancet 2017. PMID 28336049[5]).
A Danish study compared 140 people with newly diagnosed overt autoimmune hypothyroidism and 560 people without thyroid disease. The most common symptoms among those with the disease were fatigue (81%), dry skin (63%) and shortness of breath (51%). Dry skin and hair loss were more frequent among the patients than among healthy people, but no single sign is reliable on its own. The more symptoms from the list, the higher the likelihood of hypothyroidism, and when none were present at all it fell to 21% of the initial likelihood. The authors’ conclusion: even a slight suspicion is a reason to get tested (Carlé A Eur J Endocrinol 2014. PMID 25305308[7]).
What burnout is
The World Health Organization (WHO) included burnout in the 11th revision of the International Classification of Diseases (ICD-11) as an occupational phenomenon, not as a medical condition. It results from chronic workplace stress that has not been successfully managed. Three signs: exhaustion, mental distance from one’s job or cynicism towards it, and a sense of one’s own ineffectiveness. The term refers only to work (WHO, ICD-11, 2019).
A practical question to ask yourself: is the fatigue linked primarily to work?
Burnout and depression are noticeably linked (correlation coefficient 0.52); the authors of the meta-analysis considered them distinct, though partly overlapping, conditions (Koutsimani P Front Psychol 2019. PMID 30918490[6]).
Thyroid test: TSH and free T4
TSH is the best single test to check whether the thyroid is working properly (Garber JR Endocr Pract 2012. PMID 23246686[1]). If TSH is raised, the doctor adds free thyroxine (T4), the gland’s main hormone. High TSH with low free T4 means overt hypothyroidism; high TSH with normal free T4 means subclinical, that is, mild hypothyroidism. Reference ranges are statistical and depend on the laboratory (Chaker L Lancet 2017. PMID 28336049[5]).
For subclinical hypothyroidism with TSH below 10 mU/L (10 µIU/mL), the guideline advises deciding on treatment individually (Garber JR Endocr Pract 2012. PMID 23246686[1]).
Cortisol: what can and cannot be checked
Morning blood cortisol together with adrenocorticotropic hormone (ACTH, the pituitary hormone that controls the adrenal glands) is needed to rule out adrenal insufficiency. The US Endocrine Society advises testing for primary insufficiency when there are signs of it; in pregnant women, with persistent nausea, fatigue and low blood pressure. Morning cortisol with ACTH is the first step if a short ACTH test cannot be done right away (Bornstein SR J Clin Endocrinol Metab 2016. PMID 26760044[8]).
Saliva cortisol “curves”, however, do not diagnose burnout. In a systematic review of 58 studies of cortisol in fatigue and burnout (33 of them in healthy people), the results almost always contradicted each other, and “adrenal fatigue” as a disease was not confirmed (Cadegiani FA BMC Endocr Disord 2016. PMID 27557747[9]).
The “Stress axis” questionnaire can help you get your bearings — it is a guide, not a diagnosis. Which tests to discuss with a doctor based on its results is covered in the article Stress axis: sleep, energy and which tests to discuss.
What else to check if fatigue persists
The doctor decides what else to test based on your symptoms and examination.
It can be both
Hypothyroidism does not protect against burnout, and burnout does not rule out thyroid disease. Even when test results on treatment return to normal, a noticeable proportion of patients still have symptoms (Chaker L Lancet 2017. PMID 28336049[5]). On the link between hypothyroidism and mood, see the article Hypothyroidism, Hashimoto’s, depression and anxiety.
What the studies showed
| What was studied | Who took part | Result |
|---|---|---|
| Symptoms in newly diagnosed overt autoimmune hypothyroidism, 2014 | 140 patients and 560 people without thyroid disease | Fatigue in 81%, dry skin in 63%; no single sign is reliable on its own |
| Causes of fatigue in family practice, review of 26 studies, 2016 | Patients with fatigue | Depression 18.5%, serious physical illness 4.3%, anaemia 2.8% |
| Burnout and depression, meta-analysis, 2019 | Studies from 2007–2018 | Noticeable link (0.52); the authors considered them distinct, though partly overlapping, conditions |
| Iron for fatigue without anaemia, 2012 | 198 menstruating women aged 18–53 with ferritin below 50 µg/L (50 ng/mL) | Fatigue fell more than on placebo (−47.7% vs −28.8%); no significant effect on quality of life or mood |
| Measures against burnout, meta-analysis, 2016 | 52 studies, 3630 doctors; overall burnout share from 14 of them | Share with burnout from 54% to 44% |
| Thyroid hormones in subclinical hypothyroidism, meta-analysis, 2018 | 21 studies, 2192 non-pregnant adults | No improvement in quality of life or thyroid-related symptoms shown |
Not everything was confirmed: in subclinical hypothyroidism in non-pregnant adults, thyroid hormones lowered TSH, but across 21 studies they did not show an improvement in overall quality of life or thyroid-related symptoms (Feller M JAMA 2018. PMID 30285179[10]). So a slightly raised TSH does not always explain fatigue.
Who should be more careful
- If you have thoughts that you do not want to live, seek help right away without waiting for test results.
- If fatigue is accompanied by persistent unexplained nausea and low blood pressure, see a doctor without delay: the guideline advises testing for primary adrenal insufficiency when there are signs of it; in pregnant women, with persistent nausea, fatigue and low blood pressure (Bornstein SR J Clin Endocrinol Metab 2016. PMID 26760044[8]).
- If you are already taking levothyroxine and the fatigue does not go away, do not change the dose yourself: discuss the dose and other causes with your doctor.
- Do not start thyroid hormones “for fatigue” without a test.
Bottom line
Hypothyroidism and burnout feel similar. Hypothyroidism often brings feeling cold, weight gain, constipation and dry skin, but no single sign is reliable on its own; burnout is exhaustion and cynicism linked to work. TSH shows whether you have hypothyroidism, with free T4 if needed; what else to check — iron, vitamins, blood sugar, mood — the doctor decides based on your symptoms and examination. Both can occur at once. You can sort out the causes of your fatigue at a consultation.
This material is for information only and does not replace a doctor’s consultation. Tests and treatment are prescribed by a doctor based on the results of an examination.
References
- Garber JR Endocr Pract 2012. PMID 23246686
- Stadje R BMC Fam Pract 2016. PMID 27765009
- West CP Lancet 2016. PMID 27692469
- Vaucher P CMAJ 2012. PMID 22777991
- Chaker L Lancet 2017. PMID 28336049
- Koutsimani P Front Psychol 2019. PMID 30918490
- Carlé A Eur J Endocrinol 2014. PMID 25305308
- Bornstein SR J Clin Endocrinol Metab 2016. PMID 26760044
- Cadegiani FA BMC Endocr Disord 2016. PMID 27557747
- Feller M JAMA 2018. PMID 30285179
Key facts
- Thyroid-stimulating hormone (TSH) is the best single test to check thyroid function in most people (Garber JR, Endocr Pract 2012).
- In newly diagnosed overt autoimmune hypothyroidism, fatigue was present in 81% and dry skin in 63%, but no single sign is reliable on its own (Carlé A, Eur J Endocrinol 2014).
- Under the 11th revision of the International Classification of Diseases (ICD-11), burnout is an occupational phenomenon, not a medical condition: exhaustion, cynicism towards work and a sense of ineffectiveness (World Health Organization, 2019).
- Among people who saw a family doctor with fatigue, depression was a common finding — in 18.5% — and serious physical illness in 4.3% (Stadje R, BMC Fam Pract 2016).
- Across 14 studies, measures against burnout reduced its share among doctors from 54% to 44% (West CP, Lancet 2016).
