McCall McPhersonFounder, Modern Thyroid Clinic.

Thyroid Hormones: T4 Risks vs. T3 Benefits Explained! #shorts

15 Oct 2026 · 1 min

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McCall McPherson breaks down a study showing high T4 increases mortality risk and osteoporosis, dementia, diabetes, and heart disease. Higher-normal T3 does the opposite: lower mortality, better cardiovascular health, stronger bones, and longer working years.

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What this study showed is higher levels of T4 is associated with higher levels of mortality. It was associated with higher incidence of osteoporosis, osteopenia. It was associated with higher levels of dementia, diabetes, heart disease. Higher levels of T3, and I'm not talking like unending, right? Like, everything's in balance. We're talking about high normal levels of T3 was associated with lower risk of mortality, lower risk of heart disease, cardiovascular events, osteoporosis, osteopenia, higher socioeconomic status, more hours worked, later retirement, and reduced risk of disability.