4 Needs context
T4 can convert into reverse T3 when a person is under high levels of stress.
"the T4 definitely can go to reverse T3 if you're stressed out of your mind like [laughter] I have been." (said at 0:23:15)
Thyroxine (T4) is converted into the inactive metabolite reverse T3 (rT3) through inner-ring deiodination (primarily via type 3 iodothyronine deiodinase). In situations of severe physiological stress—such as critical illness, major surgery, trauma, or severe caloric restriction (a pattern known as nonthyroidal illness syndrome or euthyroid sick syndrome)—active T3 levels decline while reverse T3 levels frequently rise. However, while this metabolic shift is well-documented in major somatic illness and acute hospital settings, evidence that everyday psychological or emotional stress produces a clinically significant conversion of T4 into reverse T3 is limited.
- context: Acute development of low T3 syndrome and changes in pituitary-adrenocortical function afte… (Scandinavian journal of clinical and laboratory investigation 1992) · cited 4x in the literature
"Though no changes in the level of T4 were found, the level of T3 was significantly decreased and that of rT3 was significantly increased on Day 1 after surgery." (abstract, passage verified)
pubmedfull study (doi) - supports: Non-thyroidal illness in the ICU: a syndrome with different faces. (Thyroid : official journal of the American Thyroid Association 2014) · cited 315x in the literature
"Critically ill patients typically present with low or low-normal plasma thyroxine, low plasma triiodothyronine (T3), increased plasma reverse T3 (rT3) concentrations, in the absence of a rise in thyrotropin (TSH). This constellation is referred to as nonthyroidal illness syndrome (NTI)." (abstract, passage verified)
pubmedfull study (doi) - supports: Clinical and laboratory aspects of 3,3',5'-triiodothyronine (reverse T3). (Annals of clinical biochemistry 2021) · cited 27x in the literature
"Reverse T3 (3,3',5'-triiodothyronine or rT3) is the third most abundant iodothyronine circulating in human blood and is produced by the inner ring deiodination of the pro-hormone thyroxine (T4)... Serum rT3 concentration is increased as part of the non-thyroidal illness syndrome, and by administration of common medications such as amiodarone which inhibit the metabolism of rT3." (abstract)
pubmedfull study (doi)
Every person has cancer cells continuously present in their body that the immune system constantly destroys.
"the cancer cells that we all have in our body, FYI, we all have them, but your immune system is constantly destroying them." (said at 0:29:35)
The claim states that every person has cancer cells continuously present in their body that are constantly destroyed by the immune system. In immunology and oncology, the framework of cancer immunoediting recognizes an "elimination phase" (or immunosurveillance), in which the immune system detects and destroys nascent transformed cells. Furthermore, genomic sequencing shows that healthy individuals accumulate somatic mutations and clonal expansions in normal tissues throughout life. However, phrasing this as "we all have cancer cells" is a slight oversimplification; histologically normal tissues accumulate driver mutations and altered cells, but possessing mutated or aberrant precursor cells is not clinically or pathologically synonymous with having malignant cancer. The core physiological mechanism of immune elimination (immunosurveillance) acting against newly transformed or aberrant cells is well supported.
- supports: The immunobiology of cancer immunosurveillance and immunoediting. (Immunity 2004) · cited 3005x in the literature
"The last fifteen years have seen a reemergence of interest in cancer immunosurveillance and a broadening of this concept into one termed cancer immunoediting. The latter, supported by strong experimental data derived from murine tumor models and provocative correlative data obtained by studying human cancer, holds that the immune system not only protects the host against development of primary nonviral cancers but also sculpts tumor immunogenicity. Cancer immunoediting is a process consisting of three phases: elimination (i.e., cancer immunosurveillance), equilibrium, and escape." (abstract, passage verified)
pubmedfull study (doi) - supports: Cancer immunoediting: antigens, mechanisms, and implications to cancer immunotherapy. (Annals of the New York Academy of Sciences 2013) · cited 361x in the literature
"Accumulated data from animal models and human cancer patients strongly support the concept that the immune system can identify and control nascent tumor cells in a process called cancer immunosurveillance." (abstract, passage verified)
pubmedfull study (doi) - context: Clonal Evolution in Healthy and Premalignant Tissues: Implications for Early Cancer Interc… (Cancer prevention research (Philadelphia, Pa.) 2023) · cited 22x in the literature
"Histologically normal human tissues accumulate significant mutational burden with age. ... Interestingly though, the presence of these mutations and positive clonal selection in isolation remains a poor indicator of potential future cancer transformation in solid tissues." (abstract)
pubmedfull study (doi)
Eighty to ninety percent of women diagnosed with hypothyroidism have Hashimoto's thyroiditis.
"and what, like 80, 90% of women with hypothyroidism have Hashimoto's." (said at 0:41:30)
In iodine-sufficient regions, chronic autoimmune thyroiditis (Hashimoto's thyroiditis) is the underlying cause in the vast majority (often estimated between 80% and 90%) of non-iatrogenic primary hypothyroidism, predominantly affecting women. However, globally, iodine deficiency remains a leading cause in iodine-deficient areas, and a substantial minority of hypothyroidism cases arise from iatrogenic causes (such as thyroid surgery or radioactive iodine therapy) and medication side effects.
- context: Epidemiology and prevention of clinical and subclinical hypothyroidism. (Thyroid : official journal of the American Thyroid Association 2002) · cited 349x in the literature
"Iodine deficiency is the most common cause of hypothyroidism worldwide. In persons living in iodine-replete areas, causes are congenital, spontaneous because of chronic autoimmune disease (atrophic autoimmune thyroiditis or goitrous autoimmune thyroiditis [Hashimoto's thyroiditis]), or iatrogenic because of goitrogens, drugs, or destructive treatment for thyrotoxicosis." (abstract, results, passage verified)
pubmedfull study (doi) - context: Hypothyroidism. (Lancet (London, England) 2024) · cited 118x in the literature
"The most common cause of hypothyroidism is chronic autoimmune thyroiditis (Hashimoto's thyroiditis), although other causes, including drugs (such as amiodarone, lithium, and immune checkpoint inhibitors), radioactive-iodine treatment, and thyroid surgery, are frequent. Historically, severe iodine deficiency was the most common cause." (abstract, results, passage verified)
pubmedfull study (doi) - context: Hashimoto's thyroiditis: from pathogenesis to clinical management. (Frontiers in endocrinology 2026) · cited 4x in the literature
"Hashimoto's thyroiditis (HT) is a chronic autoimmune thyroiditis characterized by thyroid-specific autoantibodies (TPOAb, TGAb) positivity and lymphocytic infiltration, and is a major cause of hypothyroidism in iodine-sufficient regions. Epidemiological data show a significant increase in the prevalence of HT, which is about four times more common in adult women than in men." (abstract, results, passage verified)
pubmedfull study (doi)
Hypothyroidism causes myxedema, characterized by visible thickening and swelling of the face, neck, skin, and back of the arms rather than just adipose tissue.
"The myxedema, the swollen face, the moon face, the thickening. Like if you're looking at yourself and your your face, like it's not just fat. It's literally like a thickening of the the face, of the neck, of the skin, back of arms. It's it's thicker." (said at 1:03:56)
Generalized myxedema is a hallmark cutaneous manifestation of severe hypothyroidism caused by the accumulation of hydrophilic glycosaminoglycans (notably hyaluronic acid) in the dermis and subcutaneous tissues, which produces non-pitting edema, facial/periorbital puffiness, and skin thickening rather than simple adipose tissue expansion. However, the specific clinical term 'moon face' (moon facies) is classically a feature of Cushing's syndrome (hypercortisolemia) rather than hypothyroidism.
- context: Cutaneous manifestations of endocrine disorders: a guide for dermatologists. (American journal of clinical dermatology 2003) · cited 235x in the literature
"In patients with hypothyroidism, there is hair loss, the skin is cold and pale, with myxedematous changes, mainly in the hands and in the periorbital region. The striking features of Cushing syndrome are centripetal obesity, moon facies, buffalo hump, supraclavicular fat pads, and abdominal striae." (abstract, passage verified)
pubmedfull study (doi) - supports: Thyroid hormone action on skin. (Dermato-endocrinology 2011) · cited 55x in the literature
"The name "myxedema" refers to the associated skin condition caused by increased glycosaminoglycan deposition in the skin. Generalized myxedema is still the classic cutaneous sign of hypothyroidism. It is caused by deposition of dermal acid mucopolysaccharides, notably hyaluronic acid. Despite its appearance, the skin does not pit with pressure." (abstract, passage verified)
pubmedfull study (doi)
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