Patients and doctors are often told there’s an ideal “target” for TSH levels. Some believe that in thyroid therapy, your TSH should be below the upper reference limit, some say it should be below 2.5, and a minority will even say it should be suppressed entirely whether or not you are a thyroid cancer patient. Some will say, with more wisdom and discretion, that a good TSH level also depends on how much thyroid tissue you have, or what type of thyroid therapy you are on. Patients often say in sympathy with a fellow patient who is suffering with a …
Category: TSH hormone
As of 2019, still no proof that low TSH causes harm to bones
Many research studies have shown a strong association between low TSH and low bone mineral density or osteoporosis. As a result, many guidelines strongly caution against the risk associated with low TSH. Some doctors and thyroid patients have jumped to the conclusion that a low TSH “causes” osteoporosis. Some even believe a low TSH must be avoided at all costs during thyroid therapy, even if lowering their thyroid hormone dose causes chronic hypothyroid symptoms in a patient! But as of 2019, has science proven that lack of TSH “causes” harm to bones? Surprisingly, the answer is NO! Correlation is not …
Pregnancy thyrotoxicosis vs just a low TSH due to hCG hormone
Table 17.1 in Braverman & Cooper’s 2013 chapter in Werner & Ingbar’s The Thyroid textbook, 10th edition, lists many causes of thyrotoxicosis. One of the interesting causes of thyrotoxicosis, rarely mentioned in public discourse, is “Circulating hCG or Mutant TSHR [TSH receptor] hypersensitive to hCG.” What is hCG? “Human chorionic gonadotropin” is a hormone produced by the placenta after implantation. hCG is used to detect pregnancy status in some pregnancy tests. This non-TSH hormone can stimulate a thyroid gland like TSH and TSHR antibodies do. Therefore, as they stimulate a healthy thyroid, they elevate thyroid hormones. A side effect is …
How TSH ultrashort feedback works, and antibody interference
This post takes a closer look at the “ultrashort feedback loop,” the biological mechanism by which the TSHR stimulating antibody (TSAb) can oversuppress or inflate TSH in any autoimmune hypothyroid patient. The antibody’s effect alters the normal TSH-FT4 relationship. It may look like the patient has another thyroid condition: It may mimic “Resistance to thyroid hormone” (RTH) with a mid-range or higher FT4 or FT3 alongside an elevated TSH, or a high FT4 with an unsuppressed TSH. It may mimic “Central hypothyroidism” (CeH), with a mid-range or lower FT4 and FT3 alongside a low or suppressed TSH. ULTRASHORT FEEDBACK LOOP …
TSH “can be very misleading” during thyroid therapy, say researchers
How many treated hypothyroid patients’ TSH has fallen below range even when both their thyroid hormones are in normal range and when they have no symptoms or signs of hyperactivity or hypermetabolism? In my observation on thyroid patient forums, the answer is “too many.” It’s common among thyroid patients to resort to such forums for peer support when their doctors lower their thyroid hormones based on the lower TSH alone. This is an important blind spot in TSH-centered therapy guidelines that must be addressed in a series of posts that examine the topic of a low TSH’s uncertain relationship to the …