Here's Why You Still Feel Like Sh*t After Doing Everything Right...

Dave Asprey

Mar 19, 2026

Episode description

Your thyroid controls your energy, your metabolism, your testosterone, your mood, and your ability to think clearly. Most doctors are testing it wrong and treating it wrong, and this episode tells you exactly what to do instead.

-Watch this episode on YouTube for the full video experience: https://www.youtube.com/@DaveAspreyBPR

Host Dave Asprey sits down with McCall McPherson, a physician associate, TEDx speaker, and founder of Modern Thyroid Clinic, Modern Weight Loss, and the advocacy platform Thyroid Nation. McPherson has been honored on the 2024 and 2025 Inc. 5000 lists and named a 2025 Top 500 Inc. Female Founder. She hosts the Modern Thyroid and Wellness podcast and built her entire practice around thyroid care after being failed by conventional medicine while managing her own hypothyroidism. She treats patients nationwide via telemedicine and has become one of the most trusted voices in functional medicine thyroid care.

Dave and McCall expose why standard TSH-only testing catches just 1 to 2 percent of actual thyroid variation, why the medication most doctors prescribe (Synthroid/levothyroxine) fails a massive percentage of patients, and why T3 is the active hormone that mainstream medicine has been trained to fear without good reason. They also get into how fluoride in tap water, bromine in American wheat, mold exposure, dairy, gluten, and oxalates directly suppress thyroid function and drive autoimmunity. If you want to optimize your metabolism, protect your mitochondria, support brain optimization, and stop leaving your longevity on the table, thyroid is the first domino.

This is essential listening for anyone serious about biohacking, human performance, anti-aging, functional medicine, supplements, sleep optimization, and using smarter not harder strategies to take control of your biology.

You'll Learn:

Why testing TSH alone misses thyroid dysfunction in the vast majority of people
What a full thyroid panel actually includes and the optimal ranges for T4, T3, and reverse T3
Why T4-only medications like Synthroid fail and what works better
How low thyroid directly tanks testosterone and libido in both men and women
The environmental triggers destroying your thyroid, including fluoride, bromine, mold, and inflammatory foods
How Hashimoto's connects to broader autoimmune risk and what drives it into remission
Why kids are being misdiagnosed with ADHD when the real issue is hypothyroidism
The supplements and cofactors (selenium, zinc, magnesium, ashwagandha, tyrosine) that support thyroid activation
How thyroid optimization connects to metabolism, dementia prevention, cardiovascular health, and economic outcomes
When to use T3 only vs. a T3/T4 combination, and how

Mindsip insights from this episode:

Reassess T3 hormone levels to reduce mortality risk

Doctors are trained to fear the active T3 hormone, but research shows higher T3 levels decrease mortality while higher T4 levels increase it.

#hormones

#mortality

Recognize limitations of T4 medications like Synthroid for effective hormone conversion

T4-only medications like Synthroid are like crude oil and are ineffective for many people who cannot convert it into the usable 'gasoline' T3 hormone.

#hormones

Identify dairy as a primary inflammatory trigger for Hashimoto's

In thousands of inflammatory food tests on Hashimoto's patients, dairy shows up as an inflammatory trigger about twice as often as gluten.

#autoimmunity

#dairy

Recognize low testosterone as early sign of hypothyroidism

Low testosterone is often the very first hormonal dysfunction to appear with hypothyroidism, with 99.5% of the speaker's patients having extraordinarily low levels.