She had been my patient for several years when she came in one day for a routine symptom assessment. She was around 60, from Menlo Park, and had been on Synthroid for twenty years. Her endocrinologist had been managing her thyroid the entire time. Every year, her TSH came back in the normal range. Every year, she was told her thyroid was fine.
When we went through her symptom checklist together, she had checked off more than ten thyroid symptoms, all of which she had chalked up to aging:
- Weight gain
- Fatigue
- Anxiety
- Joint pain
- Morning stiffness
- Easy bruising
- Hair loss
- Heart palpitations
- Ringing in the ears
- Hoarse voice
- Constipation
- Cold hands and feet
- Muscle pain
Symptoms that had been chased for other causes for years, because the one thing driving most of them was considered managed.
I suggested we run a complete thyroid panel. Not just TSH. Everything.
What We Found
Her TSH was exactly where her endocrinologist wanted it. Perfect, by that single measure. But when we looked at the full picture, a different story emerged entirely.
Her free T3 and total T3 were not just suboptimally low. They were actually low. Her reverse T3 and T3 uptake were both within the standard clinical reference range, but when read through an optimal lens they told a different story. Her T3 uptake was too low, most likely driven by estrogen and insulin surges raising her binding proteins and locking thyroid hormone away from her cells. Her reverse T3 was too high, pointing to the liver and gut being involved in why her body could not effectively convert the T4 she had been taking into active T3. Synthroid is a synthetic T4. It is not biologically identical to the hormone your thyroid produces. Her body was supposed to convert that T4 into active T3. It was not doing that effectively. And nobody had looked to see why, because TSH said everything was fine.
TSH does not even come from the thyroid. It is a feedback signal from the brain telling the thyroid to produce more hormone. When you are giving someone exogenous T4, TSH quiets down because the brain thinks the job is done. It does not tell you whether the T4 is actually being converted into something the body can use. That requires a completely different set of markers.
What Changed
We discussed switching from Synthroid to a desiccated thyroid product that contains both T3 and T4. She was open to it. We made the change.
About a month later she came in and said her hairdresser had commented on how much thicker her hair was looking. There was new growth coming in, little baby hairs all around her hairline. Her hair looked healthier. She was sleeping better. Her energy was up. Her joints were not as stiff in the mornings. She went back through the symptom list and most of what she had checked off was either gone or significantly improved.
She was stunned. She had been on thyroid medication for twenty years. She had assumed her thyroid was handled. What she did not know was that her medication was handling one number and leaving the underlying conversion problem completely unaddressed.
What Happened Next
About three months later, she went back to see her endocrinologist for her regular appointment. He reviewed her labs, saw that she was no longer on Synthroid, and told her she had made a mistake. He was not open to discussing the complete panel results. He put her back on Synthroid.
Her hair started falling out again. The fatigue came back. The joint pain returned. The symptoms she had just watched disappear came back one by one.
About six months after that, she emailed me. She said she was embarrassed and asked if she could come back. She wanted to fix it again.
We did.
I tell this story not to criticize any individual physician but because it illustrates something I see consistently: when a woman's TSH is in range, the conversation about her thyroid is considered closed. The symptoms she is living with get attributed to other causes, other conditions, other explanations. The medication gets credited with doing its job. And the actual picture, what is happening at the level of conversion, of cellular availability, of the systems driving the whole process, never gets looked at.
What a Complete Thyroid Panel Actually Shows
TSH and T4, the two markers most physicians rely on, tell you whether the gland is being stimulated and whether it is producing raw material. They do not tell you whether that raw material is being converted into the active hormone your cells actually use, whether something is blocking that conversion, or whether your immune system is attacking your thyroid in the background.
A complete panel gives you the full picture — what is being produced, what is available to cells, what is being blocked, and whether the immune system is part of the story. It includes:
- TSH
- Free T3
- Total T3
- Free T4
- Total T4
- Reverse T3
- T3 Uptake
- Anti-TPO antibodies
- Anti-thyroglobulin antibodies
In twenty years of managing this woman's thyroid, nobody had run that panel. The answer to why she still had more than ten thyroid symptoms on a full dose of thyroid medication was sitting in tests that had never been ordered.
If you have been on thyroid medication and still feel exhausted, foggy, cold, or symptomatic in any of the ways she was, the panel you have been managed on may be incomplete. That is not a small distinction. It is the difference between treating a number and treating the person.
For the full clinical breakdown of what each marker in a complete thyroid panel measures and why it matters, read the full article here: Twenty Years on Thyroid Medication and Still Symptomatic: What Synthroid Cannot Do That a Complete Panel Reveals.
If you are in Menlo Park, Palo Alto, Atherton, Los Altos, Woodside, Portola Valley, or Redwood City and you want to know what your thyroid is actually doing, there are two ways to start.
If you want to talk through your symptoms first, schedule a Discovery Call.
If you are ready to get started, book the Discovery Experience.
Frequently Asked Questions
Can I still have thyroid symptoms if my TSH is normal?
Yes. TSH is a pituitary signal, not a direct measure of thyroid function at the cellular level. It can look perfectly normal while free T3 is low, reverse T3 is high, and your body is not effectively using the thyroid hormone it has. This is one of the most common patterns I see in women who have been told their thyroid is managed.
Is Synthroid the wrong medication for everyone?
No. Synthroid works well for many people. The issue is when someone is on T4-only medication and their body is not converting T4 to active T3 effectively. In that case, adding T3 through a desiccated thyroid product or a compounded T3/T4 combination often produces a dramatically different result. The right medication depends on what the complete panel shows, not on what the TSH says.
What causes poor T4 to T3 conversion?
Liver dysfunction, gut dysbiosis, blood sugar dysregulation, chronic stress, nutrient deficiencies particularly in selenium and zinc, and toxic burden are among the most common drivers. This is why looking at thyroid conversion in isolation from the rest of the clinical picture misses the point. The conversion problem is rarely the whole story. Something is causing it.
How do I get a complete thyroid panel?
You can request one from your physician, though many will only order TSH and sometimes T4. A naturopathic physician or functional medicine practitioner can order the full panel including reverse T3, T3 uptake, and both antibody markers. This is part of what I assess in every thyroid workup.
Do I need a referral to see you?
No referral needed. You can book directly through a Discovery Call or the Discovery Experience.
Related reading:
- Your Thyroid Is Not Fine Just Because Your TSH Is Normal
- What a Complete Lab Panel Reveals That 30 Years of Doctor Visits Missed
- Why Hormone Replacement Alone Is Not Enough
- Why Stress Hits Women Over 45 Completely Differently
For further reference on thyroid hormone conversion and treatment, the American Thyroid Association provides reliable patient-facing resources.