Hypothyroidism is a medically recognised endocrine disorder where the thyroid gland produces insufficient thyroid hormones (T3 and T4). These hormones regulate metabolism, energy production, and temperature control. When levels are low, the body slows down, leading to:
Persistent fatigue

Weight gain despite normal eating habits
Constipation and dry skin
Sensitivity to cold
Depression or slowed cognition
Common causes include autoimmune disease (Hashimoto’s thyroiditis), iodine deficiency, or post-surgical changes.

Adrenal fatigue, on the other hand, is a term used in functional and integrative medicine to describe a stress-related state of exhaustion. It’s thought to result from prolonged physical, emotional, or environmental stress that overtaxes the adrenal glands, which produce cortisol and other stress hormones. Symptoms may include:
Chronic tiredness not relieved by sleep
Brain fog and poor concentration
Difficulty handling stress or feeling “wired but tired”
Cravings for salt or sugar
Sleep disturbances

While adrenal fatigue is not formally recognised in conventional medicine, many patients report these symptoms. They may overlap with other conditions such as thyroid dysfunction, sleep disorders, or nutrient deficiencies. A thorough evaluation is essential to rule out true adrenal insufficiency or other underlying causes.