Few systems affect how you feel more than the thyroid. Dr. Allen calls it "the general of the system" — the gland that helps set the pace for energy, metabolism, temperature, mood, and mental clarity. When it slows down, everything slows with it. And yet millions of people with real thyroid symptoms are told their thyroid is "fine."
The reason is almost always the same: they were tested with a single number.
Why TSH Alone Is Not Enough
Most standard workups check only TSH — a pituitary signaling hormone. TSH is useful, but it is one message in a much longer conversation. It does not directly tell you how much active thyroid hormone is reaching your cells, or whether your immune system is quietly attacking the gland. A person can have a "normal" TSH and still have low free T3, the most active form of thyroid hormone your body actually uses.
As Dr. Allen explains in his chapters on the thyroid and on Hashimoto's, a more complete panel is often what finally connects the dots.
- Free T4 and Free T3The actual thyroid hormones available to your cells — not just the pituitary's signal.
- Thyroid antibodies (TPO, TgAb)These can reveal Hashimoto's, an autoimmune cause of hypothyroidism, sometimes years before TSH drifts out of range.
- Reverse T3 and nutrient statusContext that helps explain why symptoms persist even when the basic numbers look acceptable.
The Symptoms Worth Taking Seriously
Persistent fatigue, cold hands and feet, weight that won't move, thinning hair, constipation, dry skin, brain fog, and low mood are all classic signals. Any one of them can have other causes — but together, and especially when they have crept in over time, they deserve a fuller look than a single lab value can provide.
What Care Can Look Like
When the picture is clear, treatment is rarely about chasing a number. It is about restoring what is missing — carefully and gradually — and paying attention to how you actually feel and function along the way. For some people that includes thyroid support; for others it means addressing inflammation, sex hormones, insulin, or nutrients that influence how the thyroid works.
This is exactly the kind of "normal but not well" story at the heart of Dr. Allen's book, Why Do I Feel Like This?. If it sounds familiar, take our 3-minute quiz, learn more about our hormone therapy program, or book a consultation.