Dr Cobi

"TSH in range. Brain fog winning. The two can coexist for years before anyone runs the test that actually catches it."

The thyroid cluster that gets missed most often:

— Brain fog
— Constipation
— Low energy, especially in the afternoon
— Weight that won't move despite eating well

TSH is the signal from your pituitary to your thyroid. It does not tell you whether the thyroid is converting T4 to T3 at the cellular level. It does not tell you what's actually available for the brain and body to use.

A full thyroid panel includes: TSH · Free T4 · Free T3 · Reverse T3 · Anti-TPO · Anti-TG

When Free T3 is suboptimal and TSH is in range, the conversion pathway is the problem — and no standard panel will find it unless you ask.

This is not a rare pattern. It is a missed one.

Save this and bring it to your next appointment if you've been told your thyroid is fine.