Why Synthroid Isn’t Working – The Shocking Truth About T4, T3 & Thyroid Symptoms

31 Jul 2025 · 16 min
16:19

McCall McPherson explains why Synthroid and other T4-only thyroid drugs often fail: the body struggles to convert T4 to T3, and reverse T3 accumulates over months. Standard lab targets miss the problem. He recommends gradually reducing T4 dose while adding T3, aiming for TSH around 0.9-1.2 and T3 at 3.6-4.2.

Questions this video answers

89 percent.

About 12.5 micrograms per visit.

Approximately 0.9 to 1.2.

About 3.6 to 4.2.

Initial acute improvement in the first weeks; partial relapse over ~3–6 months; slow accumulation of reverse T3 over ~6–18 months.

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