TSH is the most common thyroid lab test, but it does not test thyroid hormones directly. TSH is a pituitary hormone usually secreted in response to low thyroid hormones. Higher TSH means the body is asking for more thyroid. The normal range is usually around 0.4 to 4.0. But

The thyroid gland produces several thyroid hormones, two of which are significant. The first is T4, the storage form of thyroid hormone. It needs a little modification to become thyroid hormone proper (T3). T4 is released into circulation and then converted, as needed, all going

T3 is THE active thyroid hormone. It activates cell receptors, initiates gene expression, controls metabolism and growth, influences temperature, heart rate, etc. T3 is where it's at... but only when it reaches and activates the cell receptors. So, while T3 is the most important

Reverse T3 (rT3) is an anti-thyroid hormone made from T4 - it blocks the effects of T3. High rT3 can invalidate seemingly good T3 levels because while there may be a lot of T3 available, much of it is blocked from reaching the cell and doing its work.

The Basal Temperature Test: Broda Barnes developed the basal temperature test for thyroid function after realizing that basal temperature usually corresponds to basal metabolic rate. The basal metabolic rate test measures oxygen consumption when a person is at rest. The basal

Basal Temperature Testing: Barnes recommended using a mercury thermometer under the armpit for 10 minutes first thing after waking to get a reading of the basal temperature. Nowadays, most people use digital oral thermometers because they are more convenient, though there is

Resting heart rate is another factor strongly influenced by thyroid hormone activity. Ray Peat said that a healthy pulse is around 85 bpm. A pulse lower than that could indicate functional hypothyroidism, which means that adequate T3 is not getting to the cell. Pulse changes in

Targets: None of these tests are perfect, and optimal ranges are mostly guidelines; however, here are some ranges to aim for. TSH - Below 2.0 T3 - Top third of the normal range T4 - Top third of normal range (less important) rT3 - The lower part of the normal range Basal

Article on Substack: https://lowmegatron.substack.c...

@lowmegatron Exceptional, fact filled post. My only addition would be that if somebody is going to do a complete thyroid panel to include the thyroid antibodies (TPOAb and TgAb). If these are elevated, it would indicate that your immune system is actually attacking your thyroid.

@GentlemanRich1 Thank you, yes, I may do a post about antibodies in the future.

@lowmegatron Just had my TPO tested for the first time ever, it was 134. Thyroid has been low for a few years (TSH high, T4 normal). Grok says Hashimotos, why was TPO never tested before 😑

@Jillybop13 It’s crazy how badly thyroid patients are treated in many places.

@lowmegatron what if THS is around 2.90 ?

@pers3eus It's a little high. Recent papers call for an upper cutoff of 2.5 or 2.0. Ray Peat said 1.0 seemed reasonable. Usually at that range it can be improved without medication.

@lowmegatron Same test for pediatrics? Our endo refused to test other than TSh and t3. She have Down syndrome and is only 4

@_lei_la_ni_ Probably same tests, probably very different ranges for most of those. Certainly for pulse.

@lowmegatron Thank you for the detailed article! So what do you do if T3 is not reaching your cells? Pretty sure mine is not! TSH is high, 4.4, T4 low 0.79, basil temp. 97.2 a few hours after waking and pulse 60 bpm. Additionally, I am taking 115mg of NP Thyroid each day. HELP!😭

@5d2023 I would test T3 first.

@lowmegatron I have both hoshimotos and Graves’ disease! So fun! 😭

@JannaHilton1 Do you go from hyper to hypo or is it more like Graves' with TPOab?

@lowmegatron I love your thyroid threads. Can you do one on hashimotos?

@Stacy_4_Trump Thanks. I probably will at some point.