TSH (thyroid-stimulating hormone) is made by the pituitary gland to control how much thyroid hormone your body produces. When thyroid hormone levels (T3, T4) are low, TSH rises to “push” the thyroid into working harder. A high TSH therefore usually means your thyroid is underactive — a condition called hypothyroidism.
Is a TSH level of around 6 considered high?
Most labs define the upper limit of normal near 4.0–4.5 mIU/L, so a TSH of about 6 is mildly elevated. If T4 is normal, this is often called subclinical hypothyroidism and may simply be monitored.
Can high TSH return to normal?
Yes. TSH can normalize after correcting iodine intake, recovering from illness, adjusting thyroid-affecting medications, or beginning thyroid hormone therapy if needed. Repeat testing helps clarify the trend.
When should I worry about high TSH?
High TSH requires closer attention if it persists on repeat tests, rises over time, is accompanied by low T4, or is associated with positive thyroid antibodies suggesting Hashimoto’s thyroiditis. Symptoms like fatigue, cold intolerance, or weight changes also support further evaluation.
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