Thyroid Hormone Free T3 Has a Daily Rhythm
Tuesday April 22, 2008
Interesting, new research published online by the Journal of Clinical Endocrinology & Metabolism has found that Free T3 has a circadian (daily) rhythm, much like thyroid stimulating hormone (TSH) does.
TSH levels reach their maximum between 2 and 4 a.m., and are at their lowest between 4 and 8 p.m. It turns out that the Free T3 levels peak approximately 90 minutes after TSH, but they don't peak and dip to quite the same extent as TSH. Since only 20 percent of T3 is derived from the thyroid itself, and the rest comes through conversion from T4 to T3, apparently, TSH changes are stimulating thyroid hormone release, which result in the Free T3 changes.
Source: W. Russell, et. al. "Free triiodothyronine has a distinct circadian rhythm that is delayed but parallels thyrotropin levels," Journal of Clinical Endocrinology & Metabolism, March 25, 2008, Online
Comments
this is more question than comment–what is happening when my T-3 is running 200,but my TSH is normal?
As far as I know, TSH is fairly useless in determining if one is actually hypo and Free T3 should be at least 350.
Interesting…perhaps he could explain away how an entire immediate family with births in Mar, April, May, Aug & Nov could be afflicted, perhaps by some common sign we share! LOL
I thought Oprah had more snap than to swallow this.
my temperature is about 94.5 3:30pm that is low doctor says my blood work is fine have goiter + 5 nodules. Ihave inomnia weight goes up& was really down 5′6′ 100lbs take meds gained 20lbs. took isodols iodine j\ust started * thyroid helper i get cold thinning hair & skin…