Thyroid-stimulating hormone (TSH) — a window into your metabolism
by Marcelle Pick, OB/GYN NP
Your thyroid is central to your body’s metabolism. By doing a TSH test, we can determine how much thyroid-stimulating hormone is circulating in your blood, which provides insight into how your thyroid and metabolism are functioning. When TSH is high, it indicates that the thyroid might be sluggish or hypoactive, hence the body produces more “stimulating” hormone. If TSH is low, the thyroid might be hyperactive.
Depending on the practitioner, this test is generally ordered based on your symptoms, though I check TSH routinely on my patients. Hypothyroidism results in symptoms of a sluggish metabolism, such as fatigue, weight gain, dry skin, and cold intolerance, while hyperthyroidism often leads to the opposite: weight loss, nervousness, hand tremors, increased heart rate and insomnia.
Though the “normal” range for TSH can vary depending on labs, practitioners, and individuals, in 2002 the American Association of Clinical Endocrinologists set the normal limits as a TSH between 0.30 and 3.04. Generally speaking, I think women should be under 2.00 for TSH — and free of symptoms. If a patient of mine is above 2.00, or if she has symptoms of a thyroid disorder, I try to get to the root of the issue. This may mean more detailed tests to gain a better understanding of how the thyroid is performing or looking into other causes. The thyroid is linked to so many different organs and systems in the body that imbalances in other places, such as the adrenals, may be at play. For more information on thyroid testing, see my article on thyroid testing for hypothyroidism.