Abstract
# Your Thyroid Panel Is One Number — And That's Why You Still Feel Like Garbage ## The TSH-only screening trap You went to your doctor because you're tired all the time. You've gained 12 pounds you can't explain. Your hair is thinning, your hands are cold, your gut is sluggish, and your brain feels like it's running through wet sand by 2 p.m. They ran "thyroid labs." The result came back as a single number on the patient portal: **TSH**. It was inside the lab's reference range — somewhere between 0.5 and 4.5 mIU/L. The portal said "normal." The doctor said your thyroid is fine. They suggested stress, sleep, maybe an antidepressant. You walked out of that appointment knowing something was wrong and unable to prove it. That's the trap. The standard primary-care thyroid workup in the United States is **one biomarker** — TSH — and it routinely misses functional thyroid dysfunction in symptomatic adults. The thyroid system has at least six markers that matter. Most people get screened on one. And the "normal range" for that one number is the subject of a 20-year argument the average internal medicine practice never resolved. This article walks through what's actually happening, what the published research says, and what a serious thyroid workup looks like when you're symptomatic and your single TSH number says "you're fine." --- ## Why TSH alone doesn't tell the story TSH (thyroid-stimulating hormone) is made by the pituitary gland, not the thyroid. It's the brain's signal telling the thyroid to produce more hormone. When your thyroid output drops, the pituitary cranks up TSH. When thyroid output is high, TSH falls. That makes TSH a useful proxy — *if* the feedback loop is intact. But TSH tells you nothing directly about: - **How much T4 your thyroid is actually producing** (the storage hormone). - **How much T4 your body is converting to T3** (the active hormone — the one that runs your metabolism). - **Whether your immune system is attacking your thyroid** …
All information is presented for Research Use Only (RUO). Not medical advice.