Thyroid conditions
A common cause of hormonal imbalance, thyroid disease can trigger production of too much thyroid hormone (hyperthyroidism) or too little (hypothyroidism). The thyroid hormone is an essential part of metabolic processes in your body, so unbalanced levels can cause symptoms such as weakness and fatigue, fluctuations in weight, and muscle pain. These symptoms may be mild and can be mistaken for other conditions including depression.