@telson.health's thyroid testing claims, fact-checked

What did @telson.health actually say?

The creator listed classic hypothyroidism symptoms, including cold intolerance, hair loss, constipation, brain fog, low mood, and unexplained weight gain. Their central argument is that conventional medicine checks only TSH and calls it a day, while functional medicine practitioners order a broader panel: TSH, free T4, free T3, reverse T3, and both thyroid antibodies (TPO and TgAb). The claim is that "most of your active thyroid hormone and the function of your thyroid happens at a cell level," which justifies going beyond TSH.

They also repeated a widely circulated statistic: "1 in 8 women have low thyroid function and half of them don't know it." That framing sets up the core pitch, which is that broader testing unlocks diagnoses conventional doctors are missing.

Does the science back this up?

Partially, but not as cleanly as the video implies. The symptom list is accurate and well-supported. The criticism of TSH-only testing has real merit in certain populations. But the leap from "TSH can miss things" to "order everything including reverse T3" goes further than current evidence supports.

The American Thyroid Association acknowledges that TSH alone is the recommended first-line screen for most patients because it reflects pituitary feedback with high sensitivity (Garber et al., 2012, Thyroid). Free T4 is a reasonable add-on when TSH is abnormal or pituitary disease is suspected. Free T3 is more controversial: most endocrinology guidelines do not recommend it for routine diagnosis because its levels fluctuate significantly throughout the day and it adds limited diagnostic value over TSH plus free T4 (Ross, 2023, UpToDate).

Reverse T3 is where the video's credibility takes a hit. There is no validated clinical cutoff for reverse T3 in ambulatory patients, and most peer-reviewed endocrinology literature does not support its routine use as a diagnostic marker (Jonklaas et al., 2014, Thyroid). It rises in any illness, caloric restriction, or stress state. Using it to diagnose thyroid dysfunction outside those contexts is not evidence-based practice.

What did they get wrong (or right)?

They got the symptoms right. Cold intolerance, outer-third eyebrow loss, constipation, hair thinning, and weight gain are legitimate, textbook hypothyroid signs. Credit where it is due.

The "1 in 8 women" figure tracks with American Thyroid Association estimates, though it includes subclinical hypothyroidism, which is a different clinical conversation than overt disease.

Where they went wrong: the framing that conventional medicine is simply asleep at the wheel because it does not order reverse T3 is misleading. TSH has a sensitivity of roughly 98 percent for primary hypothyroidism (Surks et al., 2004, JAMA). It is not a blunt instrument. The issue is not that TSH is inadequate, it is that subclinical cases and autoimmune thyroid disease require clinical judgment layered on top of labs, which good conventional endocrinologists already do.

• Reverse T3 as a routine marker: not supported by endocrinology guidelines.
• Free T3 for initial diagnosis: not recommended as a standalone screen.
• TPO and TgAb antibodies: legitimately useful for diagnosing Hashimoto's thyroiditis. This part is accurate.

What should you actually know?

If your TSH comes back normal but you still feel terrible, that is worth a follow-up conversation, not a panic. A few things matter here. First, some people feel symptomatic at TSH levels within the broad reference range. There is ongoing debate about whether the upper limit should be lowered from 4.5 to around 2.5 mIU/L (Wartofsky and Dickey, 2005, Journal of Clinical Endocrinology and Metabolism). Second, Hashimoto's thyroiditis can cause symptoms before TSH becomes abnormal, which is a real case for checking TPO antibodies in symptomatic patients with a family history. Third, many symptoms attributed to thyroid dysfunction overlap with iron deficiency, sleep disorders, depression, and perimenopause. Ordering a broader panel without ruling those out is just running up lab costs.

The functional medicine framing around lifestyle, sleep, stress, and gut health is not wrong in principle. Chronic stress does elevate cortisol, which can suppress thyroid hormone conversion. But that is not the same as saying a reverse T3 panel will fix it. The answer there is addressing the stressor, not adding a lab marker with no validated treatment threshold.

Bottom line: ask your provider about free T4 and TPO antibodies if your TSH is borderline or you have a family history of autoimmune thyroid disease. Skip the reverse T3 pitch unless you are critically ill or recovering from surgery, which is the context where it actually has clinical relevance.