Tired, Wired, or Cold All the Time? Your Thyroid Might Be the Missing Piece

Why a Former Cardiac Surgery PA Digs Deeper on Thyroid Health

Before functional medicine, Dr. Gengo spent years as a physician assistant in cardiac surgery, eventually becoming Chief PA at NewYork-Presbyterian/Weill Cornell. She saw how often an undiagnosed thyroid problem was quietly driving a patient's fatigue, weight gain, and cardiovascular strain — dismissed for years because a single TSH test came back "normal."

That experience changed the question she asks. Instead of stopping at one lab value, she asks "what does the full thyroid picture — and everything connected to it — actually show." That's what brought her to functional medicine, and why she runs a comprehensive thyroid panel most doctors never order. Dr. Lisa Gengo, ND, PA-C, FMCP-M sees patients in Stamford, Greenwich, Darien, New Canaan, Fairfield, and Ridgefield, CT — and throughout the Tri-State Area via telehealth.

Why a "Normal" TSH Doesn't Mean Your Thyroid Is Fine

Most doctors screen thyroid function with a single test: TSH. But TSH is just one signal in a much longer chain — it doesn't show how well your body is actually converting and using thyroid hormone, or whether your immune system is quietly attacking your thyroid in the background.

The changes rarely show up as one dramatic symptom. Fatigue that sleep doesn't fix, weight that won't move no matter what you change, hair thinning, feeling cold when everyone else is fine, constipation, brain fog, and low mood can each get chalked up to stress or aging on their own. Together, they're a pattern that a single TSH number can completely miss.

That's the part that catches people off guard. A patient can have textbook-normal TSH and still have a thyroid that isn't functioning well for them, or an autoimmune thyroid condition years before it's caught. Dr. Gengo's approach is to look at the whole thyroid picture — TSH, free T3, free T4, and thyroid antibodies — so problems are caught while they're still easy to address.

Hashimoto's: The Autoimmune Piece Most Thyroid Testing Misses

Here's a fact that surprises most patients: the most common cause of an underactive thyroid in the U.S. isn't a thyroid problem at first — it's an autoimmune condition called Hashimoto's thyroiditis, and standard TSH testing doesn't screen for it.

In Hashimoto's, the immune system gradually attacks the thyroid gland. In the early stages, TSH and thyroid hormone levels can still look completely normal, even as the underlying autoimmune process is already active and symptoms are building. By the time TSH shifts enough to flag a standard test, the thyroid may have been under attack for years.

Dr. Gengo tests for thyroid antibodies directly, rather than waiting for TSH to cross a diagnostic line. Catching the autoimmune piece early — while nutrition, gut health, and targeted support can still make a meaningful difference — is one of the most effective things she does for a patient's long-term thyroid health.

The Nutrients Your Thyroid Runs On — and Why Deficiency Hides in Plain Sight

Your thyroid depends on specific nutrients to make and use hormone properly: iodine and selenium to produce thyroid hormone, zinc and iron to help convert it into its active form, and vitamin D to help regulate the immune response behind autoimmune thyroid disease. Low levels of any of these can quietly work against you — and most people have never had them tested, because they're not part of a standard checkup.

This is where Dr. Gengo's approach differs most from a typical visit: rather than reaching straight for a prescription and stopping there, she checks what your body may actually be low on and helps you build it back up — first and foremost through food, alongside medication when it's genuinely needed.

Her philosophy, in her words: Nutrition isn't about eating less. It's about eating more of what actually nourishes you. Dr. Gengo doesn't hand patients a restriction list. She works from abundance — real, nutrient-dense food that supports thyroid function, calms inflammation, and heals the gut at the same time, because those systems were never meant to be treated separately. Gut health and thyroid health are closely connected, and that's exactly the kind of connection a rushed 15-minute appointment doesn't have time to make.