Definition: Hypothyroidism, also called underactive thyroid, is when the thyroid gland does not make enough thyroid hormone for the body's needs, NIDDK says. Many body functions slow down. The NCI dictionary lists weight gain, constipation, dry skin and feeling cold as symptoms. NIDDK says nearly 5 in 100 Americans aged 12 and older have it, most of them mildly.
The Genotropin label says untreated hypothyroidism can blunt the response to growth hormone, and that central hypothyroidism (from the pituitary) may appear or worsen during treatment, so thyroid tests are done periodically. Other somatropin labels on this site, such as Norditropin and Skytrofa, also list hypothyroidism among the reactions seen in their trials or after approval.
NIDDK says women are much more likely than men to develop hypothyroidism, and that it is more common after age 60 and in people who had an earlier thyroid problem, thyroid surgery or radioactive iodine.
Thyroid doses change in small steps weeks apart, and absorption depends on timing around food and supplements. Logging the time of each dose and each TSH result with its date shows whether a change in levels follows a dose step or a change in routine.
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