u/SeaworthinessMany368

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I just want to clarify a few things and my own situation. I’ve been hypothyroid due to hashimotos since I was 5. I’m 18M now. For 11-12 years I’ve only taken levothyroxine until 1+ year ago I did a blood test that showed low T3. Since then my endo told me to up my T4 from 100->125. All that did was suppress my TSH very low, yet I still had low T3. In all of my blood tests this past year I’ve consistently had low T3 and normal T4. I’m very aware of my health and have almost always followed a clean Whole Foods diet this past year. I ensure my relevant bloodwork (selenium, iron, etc) is all in optimal range. I exercise (up until now since I’m bedridden), try and get optimal sleep, stay hydrated, etc. This past year has been horrid for me as my symptoms have gradually got worse until I was bedridden. I myself am very frustrated as to why my body doesn’t produce enough T3. But I just want to be cautious and not make premature assumptions. I can’t assume that I’m someone special who has a genetic issue because how come after 11-12 years I was fine and now the genetic issue has become apparent. Maybe after puberty the genetic issue became apparent? I don’t know. And I don’t know what else could be affecting my T3 at this point and sympathize with everyone who puts a lot of effort into their nutrition and lifestyle and still feels terrible. And honestly, what do I know about my body or yours? This field is definitely still foreign and has a lot of unanswered questions. But if your lifestyle choices aren’t great or you’re deficient in some nutrients, it’s better not to just blame everything on the thyroid and demand high doses of T3 or TDE.

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****** SECOND EDIT**********
Upon reading my comments and other people’s stories, it seems like a lot of people do benefit from doses higher than 5-10mcg of T3 or ratios higher than 15:1 of T4 to T3, and I can’t just ignore that. What matters most is the medication truly helps and makes you feel normal again, instead of acting like a stimulant you feel great on for a period of time, until it wares off and makes you want to up the dose.
What I want to clarify is this:
When I say most people don’t need to go over 5-10mcg of T3 it’s because as I mentioned, 80-90% of T3 comes from Deiodinase enzymes that convert T4 into T3. Your thyroid only produces 10-20%, or 5-10mcg of T3. And what I assume is that this genetic disorder that affects your D-enzymes is very rare and only applies to a small number of people. I could be wrong and maybe this disorder is more common than I thought. But, I cannot prematurely assume that I’m special and I have this genetic problem myself.
So the point I’m trying to make is:
- your thyroid is likely to be the biggest factor contributing to lower T3 production (hashimotos, thyroidectemy, EDCs, etc) rather than an inherent problem with the D-enzymes. Unless you have nutrient deficiencies (like low ferritin) that can impair T3 conversion and the effectiveness of the enzymes. These nutrient deficiencies should be addressed first.
- this means if I have an impaired thyroid or thyroidectemy, I could be missing up to 5-10mcg of T3, not 20,30,40 because the thyroid doesn’t produce that much.

But this is where conversion outside of the thyroid becomes relevant, because I do not know how truly rare a genetic disorder that impairs T3 conversion is. I do not know if there’s other factors that you cannot control outside your lifestyle choices that can impair T4 to T3 conversion. Maybe it’s the environment, maybe it’s the EDCs, I don’t know. And at that point, your T3 production is impaired beyond your thyroid and you probably do require more T3.
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As the title says, I came across this blog post by an endocrinologist and it’s very insightful and has changed my perspective on T3 treatment. He mentions a lot of things across different posts but I want to highlight these areas:

- First of all, our bodies are smart, adaptable and very good at protecting T3 levels.

This is what the author mentions “should someone have a specific defect somewhere along the pathway of thyroid hormone production, metabolism, transport, and/or action, their body will most likely compensate for that defect. Remember that the body is excellent at achieving and maintaining homeostasis; it can increase T4:T3 conversion, decrease thyroid hormone breakdown, increase thyroid hormone transport into the cell, upregulate thyroid hormone receptors, and increase thyroid hormone binding to receptors.”

Hence, I can’t just assume that I’m special and my body just doesn’t make adequate levels of T3 because even if there’s a defect affecting my thyroid hormone production, my body can adapt by adjusting other mechanisms to ensure my T3 remains normal.

- secondly, too much T3 supplementation isn’t physiological. Levothyroxine is amazing because it’s an identical replacement for the natural thyroxine hormone because it follows a physiological ratio of 15:1 of T4 to T3 just like the thyroxine hormone that the body naturally produces. A TDE however (pig thyroid hormone) that some people take follows a 4:1 ratio of T4 to T3 which isn’t natural to the body. Hence, by adding an unnecessary T3 dose or taking TDE, it can act as a stimulant which will obviously make you feel great at first, but can ween off over time, making you need more. So it can become a cycle of always chasing that high. Same as when bodybuilders use testosterone even though they’re not testosterone deficient, they obviously feel pumped on it because it’s a stimulant. At the end of the day testosterone and T3 are both hormones, and too much of any hormone can be a stimulant.

- thirdly, it’s important to understand normal physiology of T3 production in a normal (euthyroid) person and where/how it gets produced.

“In order to provide context for what a reasonable dose of T3 might be, it is critical to understand how much T3 is produced in euthyroid people. Without getting into a detailed physiology lesson, the thyroid contributes roughly 5 micrograms (mcg) of T3 to the body’s pool, with the rest produced by peripheral conversion of T4 to T3 by deiodinase enzymes. The D2 enzyme (brain, pituitary, muscle, heart, brown adipose tissue) does the bulk of the heavy lifting, producing about 20mcg of T3 per day. The D1 enzyme (liver, kidney, thyroid) contributes a small amount to the T3 pool, about 5mcg/day.”

This means that most of T3 is produced by deiodinase enzymes (roughly 25mcg). The thyroid only contributes around 16.7% or 5mcg of T3.

Think about it, unless you have some rare genetic issue that affects deiodinase enzymes. Losing the thyroid’s ability to produce T3 is likely to be the biggest problem the body can face in the entire thyroid hormone system. And the thyroid only produces 5mcg of T3. So even if you did a thyroidectomy (surgery to remove thyroid), you only ever need maximum 5 maybe 10 mcg of T3 medication. And most people still have a thyroid that partly functions, so you may even need less T3. If you take above 10mcg of T3 and still feel off, maybe you need to start considering other underlying causes to your symptoms.

This also (as you probably already know) relates to selenium, ferritin, Vitamin D, iodine, B12, and zinc levels. Because if these levels are low then that can affect T3 conversion by affecting the deiodinase enzymes and their conversion processes. So, it’s important to ensure that these levels are optimal first before considering T3 treatment.

- lastly, people really want the thyroid to be the answer to all their problems. Patients blame all of their symptoms on their thyroid when they eat like crap, sleep like crap and are constantly stressed. As unexciting as it is, your symptoms could really be down to your lifestyle, or other underlying issues like sleep apnea, other autoimmune conditions, etc.

There are so many more interesting insights that the endocrinologist talks about like:
- keto diets and how it affects the thyroid.
- T3 levels on someone who ate 100% only fat diet of 1500 cals VS a person who ate 100% only carbs diet of 800 cals.
- why reverse T3 is useless.
- the problem with alternative/ functional medicine
- how EDCs (endocrine-disrupting chemicals) can affect T3 production

This is the link to one of his blog posts that talks about T3, you can find all of his posts if you scroll down.

https://hormonesdemystified.com/t3-controversies-how-much-t3-should-i-take/

Also to clarify, I’m obviously not a professional, and most of you reading this are probably older than me. I’m just reiterating words of an expert in the field to my understanding. But also do be careful of self diagnosing or following a naturopath/functional medicine approach. If you do, I recommend to read this blog by the same author:
https://hormonesdemystified.com/the-dysfunction-of-functional-medicine/

In my opinion, taking all of these herbs, supplements, doing procedures recommended by functional doctors/naturopaths is a waste of money. Simplicity is better, eating Whole Foods, sleeping well, mental health, exercise. Like I said, our bodies are smart and know what we need given we just provide it with the right nutrition. Theres no need for some herb or some supplement like ashwaganda or large doses of selenium/iodine as that can also have harmful impacts.