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What Causes Rise In TSH Level While On Synthyroid?
My tsh my tsh has always been just above normal 4.6,4.7. My dr indicated that there was a trend toward increasintsh and prescribed synthroid 25mg. Within one month of medication my tsh has spiked to 6.0. Is just increasing the synthroid the best approach, could there be any issues causing such a dramatic spike?
Wed, 19 Sep 2018
Hi,
I understand you are concerned about your TSH while on synthroid. TSH levels respond to the amount of thyroid hormone in your system, so that when your thyroid hormone levels are low, the TSH goes up, and vice-versa.
Synthroid is thyroid hormone, and so normally would cause the TSH to go down, as you probably already know. I am assuming your doctor checked your free T4 and T3 thyroid hormone after seeing your TSH was high and that one of these was low or normal, indicating primary hypothyroidism or subclinical hypothyroidism.
Assuming this is the case, I would not be concerned. A TSH of 6.0 is not significantly different than a TSH of 4.7 (TSH can often be greater than 10). Sometimes it takes the thyroid 6-8 weeks to respond to the synthroid, so I would suggest checking it again in 4 weeks. Alternatively, the dose is very low, so your doctor may just increase it.
In summary, your TSH change was not very much, the synthroid dose may have been too low to have effect, and your thyroid may have not had enough time to fully respond to the synthroid dose. Rechecking TSH after another 4 weeks or increasing the synthroid dose should clarify these issues.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Aaron Branch, General & Family Physician
I understand you are concerned about your TSH while on synthroid. TSH levels respond to the amount of thyroid hormone in your system, so that when your thyroid hormone levels are low, the TSH goes up, and vice-versa.
Synthroid is thyroid hormone, and so normally would cause the TSH to go down, as you probably already know. I am assuming your doctor checked your free T4 and T3 thyroid hormone after seeing your TSH was high and that one of these was low or normal, indicating primary hypothyroidism or subclinical hypothyroidism.
Assuming this is the case, I would not be concerned. A TSH of 6.0 is not significantly different than a TSH of 4.7 (TSH can often be greater than 10). Sometimes it takes the thyroid 6-8 weeks to respond to the synthroid, so I would suggest checking it again in 4 weeks. Alternatively, the dose is very low, so your doctor may just increase it.
In summary, your TSH change was not very much, the synthroid dose may have been too low to have effect, and your thyroid may have not had enough time to fully respond to the synthroid dose. Rechecking TSH after another 4 weeks or increasing the synthroid dose should clarify these issues.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Aaron Branch, General & Family Physician
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