From the Guidelines
Common side effects of hypothyroidism include fatigue, increased sensitivity to cold, constipation, dry skin, unexplained weight gain, puffy face, hoarseness, muscle weakness, elevated blood cholesterol, muscle aches and stiffness, joint pain, irregular or heavy menstrual periods, thinning hair, slowed heart rate, depression, and impaired memory. These symptoms occur because thyroid hormones regulate metabolism in every cell of the body. When thyroid hormone levels are low, cellular processes slow down, causing a systemic decrease in energy production and metabolic function. This affects virtually all body systems, from cardiovascular and digestive to skin and neurological function. The severity of symptoms typically correlates with the degree of thyroid hormone deficiency and how long the body has been deprived of adequate thyroid hormone levels. Some key points to consider about hypothyroidism include:
- The most common cause of hypothyroidism in the United States is chronic autoimmune (Hashimoto) thyroiditis, as noted in studies such as 1 and 1.
- Risk factors for an elevated TSH level include female sex, advancing age, white race, type 1 diabetes, Down syndrome, family history of thyroid disease, goiter, previous hyperthyroidism, and external-beam radiation in the head and neck area, as discussed in 1 and 1.
- The USPSTF found no direct evidence that treatment of thyroid dysfunction based on risk level alters final health outcomes, as stated in 1 and 1. Most symptoms improve with proper treatment, which usually involves daily levothyroxine (synthetic T4) medication at doses typically starting at 25-50 mcg for mild cases and 75-125 mcg for more severe cases, adjusted based on blood tests every 6-8 weeks until optimal levels are achieved, as generally recommended in the management of hypothyroidism 1.
From the FDA Drug Label
6 ADVERSE REACTIONS Adverse reactions associated with levothyroxine sodium therapy are primarily those of hyperthyroidism due to therapeutic overdosage
The FDA drug label does not answer the question.
From the Research
Common Side Effects of Hypothyroidism
The common side effects of hypothyroidism include:
- Fatigue 2, 3, 4
- Weight gain 2, 3, 4
- Dry skin 2
- Constipation 2
- Cold intolerance 2, 3
- Lethargy 3
- Cognitive impairment 4
- Neuromuscular dysfunction 4
- Hypertension 4
- Dyslipidemia 4
- Infertility 4
Less Common Manifestations
In addition to the common side effects, hypothyroidism can also manifest in less common ways, including:
- Hematologic system involvement 5
- Muscular system involvement 5
- Cardiac system involvement 5
- Rheumatologic system involvement 5
Importance of Recognition
Recognizing these side effects and manifestations is important, as they can respond to thyroid hormone replacement therapy 5.