Why You Need a Full Thyroid Panel (Not Just TSH)

If you’ve ever been told, “Your thyroid labs look normal,” yet you still feel exhausted, foggy, or off, you’re not imagining things. One of the most common frustrations people face is having ongoing thyroid symptoms dismissed simply because their TSH (thyroid-stimulating hormone) level falls “within range.”

But here’s the truth:
TSH alone doesn’t tell the full story.

In functional medicine, we know that a full thyroid panel is essential to understanding how your thyroid is truly functioning, and why you might still feel unwell even when basic lab results say you're fine.

Let’s break down why this matters, what to test for, and what it can reveal about your health.

What Is TSH and Why Is It Limited?

TSH is a hormone released by the pituitary gland that tells your thyroid to produce hormones (mainly T4). If TSH is high, it suggests your thyroid isn’t doing enough, and if it’s low, your thyroid may be overactive.

But here's the problem:
TSH is just one piece of the puzzle, and it doesn’t actually measure the thyroid hormones circulating in your body or how well your cells are using them.

It’s possible to have a "normal" TSH while still having thyroid dysfunction, especially in early or subclinical stages, or when conversion and absorption are impaired.

What a Full Thyroid Panel Includes

Here’s what a comprehensive thyroid panel typically includes (and why each marker matters):

1. TSH (Thyroid Stimulating Hormone)

This hormone is produced by the brain (specifically the pituitary gland) to signal the thyroid to produce hormones. While it provides insight into how the brain is communicating with the thyroid, it doesn't reflect how much active thyroid hormone is actually available to your cells, which is why it's limited when used alone.

2. Free T4 (Thyroxine)

This is the main hormone your thyroid produces. It’s inactive until converted to T3.

3. Free T3 (Triiodothyronine)

The active form of thyroid hormone. This is what your cells actually use for energy, metabolism, and brain function. Low T3 can mean poor conversion (T4 to T3 conversion), even if TSH is normal.

4. Reverse T3 (rT3)

This is an inactive form of T3. When it’s high, it blocks your body from using active T3 properly, often due to stress, illness, or inflammation.

5. Thyroid Antibodies:

• TPO (Thyroid Peroxidase Antibodies)

• TG (Thyroglobulin Antibodies)

These test for autoimmune thyroid disease, like Hashimoto’s or Graves’. Antibodies often appear years before TSH becomes abnormal.

Why TSH-Only Testing Misses So Much

Let’s say your TSH is normal but:

• Your Free T3 is low ➝ Your cells aren’t getting enough to regulate your metabolism, mood, body temperature and energy. You feel sluggish, cold, depressed, or can’t lose weight

• Your Reverse T3 is high ➝ Your body can’t use the hormone properly

• Your Antibodies are elevated ➝ You’re in the early stages of Hashimoto’s, but no one’s told you

This happens all the time, and people go years without answers. A full panel gives you a complete picture so you can address the real issue, whether it’s inflammation, poor conversion, chronic stress, gut health, or nutrient deficiencies.

The Functional Medicine Approach

In functional medicine, we go beyond "Is this in range?" and ask:

• Are these levels optimal for your body and symptoms?

• Are you converting hormones properly?

• Are there underlying root causes like autoimmunity, stress, or nutrient depletion?

We may also look at related markers like:

• Iron/ferritin (important for thyroid hormone production)

• Vitamin D (modulates immune function and thyroid health)

• Cortisol (impacts conversion and thyroid signaling)

• Iodine, selenium, and zinc (crucial thyroid nutrients)

With this information, we build a personalized plan that supports your thyroid from every angle, nutrition, stress, gut health, and, if needed, referrals for hormone replacement therapy.

Don’t Settle for "Normal"

You deserve more than a 2-minute explanation and a basic lab test.
If you’re experiencing symptoms like:

• Fatigue

• Weight gain or difficulty losing weight

• Cold hands and feet

• Hair thinning or hair loss

• Depression or brain fog

• Constipation

• Irregular cycles or fertility issues

...and have been told your labs are fine, it’s time to dig deeper.

I have a full thyroid panel available for order in my lab shop. No doctor visit required. If you are interested in ordering, you can do so using this link: Adventure Ready Wellness Lab Shop