Fatigue is one of the most prevalent complaints amongst the general population. It is estimated that 38% of American workers report being fatigued.
The thyroid and adrenal glands regulate energy levels, metabolism, and vitality. Thyroid and adrenal disorders are two of the most common etiologies for fatigue. In this article, we will examine and differentiate between hypothyroidism and adrenal fatigue.
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Common Adrenal Fatigue Symptoms vs. Hypothyroid Symptoms
Adrenal Fatigue
HPA axis dysregulation is another term for adrenal fatigue, whereas adrenal insufficiency refers to Addison's Disease, an autoimmune condition that destroys the adrenal thyroid glands. Adrenal insufficiency occurs after periods of chronic stress or use of glucocorticoids.
Hypothyroidism
Hypothyroidism occurs when the thyroid gland produces insufficient amounts of thyroid hormone. Thyroid hormone regulates metabolism, energy, temperature regulation, reproductive health, and digestive function.
Shared Symptoms of Hypothyroidism & Adrenal Fatigue
Adrenal fatigue and hypothyroidism share several overlapping symptoms. The most common signs and symptoms include:
- Fatigue
- Weight gain
- Depression
- Muscle weakness
What is the Thyroid Gland?
The thyroid gland is an endocrine organ at the front of the neck. It is responsible for the production and secretion of thyroid hormones. The thyroid gland produces 90% thyroxine (T4), the inactive form of thyroid hormone, and 10% triiodothyronine (T3), the active form of thyroid hormone.
T4 is converted to T3 in the peripheral tissues. Thyroid hormone is produced in response to thyroid-stimulating hormone (TSH), released by the brain's anterior pituitary gland.
Thyroid hormone exerts its effects on nearly all cells throughout the body. It controls cardiac output, basal metabolic rate (metabolism), fetal growth and development, and reproductive function (4).
Hypothyroidism
Hypothyroidism may occur due to the following reasons:
- Iodine deficiency
- Autoimmunity (Hashimoto's)
- Malfunction of the pituitary gland
- Nutritional deficiency
- Environmental toxins
- Failure of peripheral receptors to respond to thyroid hormone
The most prevalent of these is Hashimoto's thyroiditis, an autoimmune form of hypothyroidism in which autoantibodies attack the thyroid gland, causing inflammation and destruction (41).
Common Hypothyroidism Signs and Symptoms
Thyroid hormone controls our body's metabolism, which generates energy for our cells to work correctly. Thyroid hormone regulates body temperature, digestive function, heart rate, and brain development. In hypothyroidism, there is not enough thyroid hormone in the body to assist in these functions, leading to the development of the following symptoms:
- Fatigue
- Weight gain
- Constipation
- Dry skin
- Weak nails
- Lower heart rate
- Cold intolerance
- Infertility
- Painless thyroid enlargement
- Stiff or weak muscles and joints
- Elevated lipid levels
(44)
Testing Thyroid Levels
To test for hypothyroidism, doctors should run the following labs:
- Thyroid-Stimulating Hormone (TSH): This hormone triggers the thyroid gland to release T4 and T3. In overt hypothyroidism (hypothyroidism caused by an underactive thyroid gland), TSH levels are elevated. In central hypothyroidism (hypothyroidism caused by dysfunction of the pituitary gland or hypothalamus), TSH levels are low or normal.
- Total and free T4: This measures levels of inactive thyroid hormone throughout the body. Free T4 is low in both primary and secondary hypothyroidism.
- Total & Free T3: This measures the levels of active thyroid hormone in the body. T3 levels tell us how well your body is converting the inactive form of thyroid hormone to its active form.
- Reverse T3: When T4 is converted to T3, it can also get converted to reverse T3. Reverse T3 is inactive and, if elevated, can cause signs and symptoms of hypothyroidism.
- Anti-TPO: Thyroid Peroxidase (TPO) is an enzyme found within the thyroid gland that plays a crucial role in producing thyroid hormones. Elevated antibodies against TPO can indicate an autoimmune condition of the thyroid gland.
- Anti-thyroglobulin: This test looks for the presence of thyroglobulin antibodies and can help detect the presence of autoimmune thyroiditis.
Our Most Popular Thyroid Tests Ordered on Rupa Health
Thyroid testing can evaluate a subset of different thyroid hormones to provide information on the functioning of your thyroid gland. Examples of thyroid panels offered through Rupa Health include:
- Comprehensive Thyroid Panel with Antibodies by Precision Point
- Comprehensive Thyroid Panel by ZRT Laboratory
- Comprehensive Thyroid Assessment by Genova Diagnostics
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What are the Adrenal Glands?
The adrenal glands are located on top of the kidneys and are essential for regulating hormone production, managing the stress response, controlling blood pressure, supporting metabolism, and modulating immune function.
The adrenal gland consists of the outer cortex and inner medulla. The outer cortex produces steroid hormones such as glucocorticoids, mineralocorticoids, and adrenal androgens, while the inner medulla secretes catecholamines, epinephrine, and norepinephrine (48).
Adrenal Fatigue
The Hypothalamic-Pituitary-Adrenal (HPA) axis is a communication system between the hypothalamus, pituitary, and adrenal glands. When the HPA axis is activated, the adrenal glands secrete cortisol, regulating inflammation, blood sugar, blood pressure, and many more vital functions.
The adrenals can become tired in chronic stress, leading to HPA axis dysregulation or adrenal insufficiency. In adrenal fatigue, the body cannot produce enough cortisol to meet the demands of everyday life, leading to fatigue and decreased stamina (30, 58).
Common Adrenal Fatigue Symptoms
After long periods of stress, the nervous system can become strained and overstimulated, leading to HPA axis dysregulation and adrenal fatigue. The most common signs and symptoms include:
- Fatigue
- Decreased stamina and energy
- Feeling "wired but tired"
- Reliance on caffeine or other stimulants throughout the day
- Decreased immune system
- Muscle weakness
- Low blood pressure
- Hypoglycemia
- PMS
- Anxiety
- Weight loss or gain
(29)
Testing for Adrenal Fatigue
Adrenal fatigue is not a diagnosis but a constellation of symptoms that can occur from HPA axis dysregulation. Dysfunction can be evaluated by assessing the following hormones and hormone metabolites:
- Morning and evening urine cortisol levels: This test monitors daily cortisol fluctuations.
- ACTH Stimulation Test: This test evaluates the adrenal glands' response to ACTH, a hormone that stimulates the production of cortisol.
- Dehydroepiandrosterone (DHEA): This hormone is produced by the adrenal glands and is a precursor to androstenedione, which gets converted to either testosterone or estrone. DHEA regulates dopamine, serotonin, and GABA and works closely with cortisol to regulate stress. Measuring DHEA output by the adrenal glands can help determine HPA axis dysregulation (adrenal fatigue).
Our Most Popular Adrenal Tests Ordered on Rupa Health
The following lab tests offered by Rupa Health can help assess adrenal function:
- HPA Profile by Sanesco
- Cortisol by Access Med Labs
- Adrenal Function Profile by Doctors Data
How to Differentiate Between These Two Conditions
Differentiating between hypothyroid and adrenal fatigue can be challenging due to the similarity of symptoms such as fatigue, weight gain, and muscle weakness.
Patients with hypothyroidism commonly experience symptoms such as hair thinning of the eyebrows, weak nails, constipation, and dry skin, which is less common in adrenal fatigue. For practitioners performing physical exams, looking for signs of thyroid enlargement can help differentiate the two conditions.
Lab tests examining thyroid function, cortisol, and DHEA levels are needed to distinguish between hypothyroidism and adrenal fatigue for definitive diagnosis and proper management (44).
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Key Takeaways
- Adrenal fatigue and hypothyroidism present with similar symptoms, such as fatigue, weight gain and muscle weakness.
- Comprehensive lab testing of thyroid and adrenal hormones is needed to differentiate between the two conditions.
- If you are experiencing symptoms, consult a trusted healthcare provider for an assessment and appropriate treatment.
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