Your Thyroid Antibodies Are Positive. Here Is What I Do Next.

She came in as a new patient at thirty-eight because she was tired in a way sleep did not fix, and because she had been bloated most afternoons for as long as she could remember. Her mother had taken thyroid medication for twenty years. Her own thyroid had been checked twice in the past five years, and both times her TSH had come back normal.

Her TSH was normal again with us. Her thyroid peroxidase (TPO) antibodies were 180, well above our lab’s cutoff of 9. Elevated TPO antibodies mean the immune system is involved with the thyroid, and in most people the reason is Hashimoto’s, even while the thyroid is still working normally.

She asked the question nearly everyone asks next: if my thyroid is still working, what is there to do?

What a positive antibody test means

Hashimoto’s is an autoimmune condition. The immune system is overactive and produces proteins, the TPO antibodies, that gradually affect the thyroid and can lead to an underactive thyroid over time. It is the most common reason a thyroid becomes underactive in this country, and it is far more common in women.

The antibodies can be positive for years before TSH ever leaves the normal range. A standard thyroid screen usually begins and ends with TSH, so many people learn they have Hashimoto’s only after the thyroid has already slowed. That is why I check TPO antibodies for every new patient, whether or not anything else points to the thyroid. It is a common condition, and finding it early gives us years to work with.

Two separate decisions

In my article on thyroid testing, I wrote that finding positive antibodies is often about watching rather than treating. That sentence describes one of two separate decisions, and the difference between them matters.

The first decision is whether thyroid hormone is needed. I read the full thyroid panel, TSH, free T4 and free T3, together with how the person feels. In my experience, free T3 is particularly informative, because T3 is the active form of thyroid hormone, and reading it alongside TSH and free T4 gives me a fuller picture than TSH alone. A positive antibody result on its own does not start thyroid hormone. Many people with positive antibodies have a thyroid that keeps up for years, and for them, watching is the right answer to that question.

The second decision is about the immune process itself, and here I do treat. I have two goals: for the person to feel better, and for the antibody number to trend down over time.

Where the immune system meets the gut

The way I explain Hashimoto’s to patients begins in the gut. The lining of the digestive tract acts as a barrier, and a large share of the immune system sits just behind it. When that barrier lets through more than it should, often called "leaky gut," the immune tissue behind it meets more than it is built to handle. In anyone with an autoimmune condition, supporting that barrier is where I start.

Research gives good reason to pay attention here. Changes in gut permeability and in the gut’s bacteria have been measured in people with Hashimoto’s, and the gut barrier is part of a widely studied model of how autoimmunity develops, alongside genetics and environmental triggers. How much each piece contributes is still being worked out. What I see in practice is that when we support the gut, patients feel better, and their antibodies often follow. I wrote about the gut as a barrier in an earlier article on absorption.

What the plan includes

Because the gut, the immune system and environmental exposures all bear on an autoimmune condition, I address all three together rather than one at a time.

Gluten. I talk with patients with Hashimoto’s about removing gluten, and the choice is theirs. In my experience, many patients with Hashimoto’s are sensitive to gluten, and removing it can ease bloating and other digestive discomfort. Celiac disease, the autoimmune reaction to gluten, is also more common in people with autoimmune thyroid disease, and the two conditions share genetic risk. Patients who remove it often feel better within a few weeks, long before any change in the antibodies. Studies of a gluten-free diet on its own have not consistently lowered antibodies. In my practice, gluten removal is one part of a larger plan, and the antibody changes I have seen came with the plan as a whole.

Gut and immune support. I use targeted supplements aimed at the gut lining and at modulating the immune response, meaning helping an overactive immune system settle rather than stimulating it. Which ones, and how much, depends on the person and is worked out together at the visit.

Vitamin D. Optimizing vitamin D is important for supporting the immune system, and in Hashimoto’s I pay particular attention to it.

Exposures. In my experience, people with autoimmune conditions are also more sensitive to environmental exposures, and some chemicals are known to interfere with the thyroid directly. Reducing those exposures where we reasonably can is part of the plan.

When the thyroid itself does need support, thyroid hormone becomes part of the plan as well, alongside everything above.

One caution: many supplements marketed for thyroid support contain iodine, and some people with Hashimoto’s are sensitive to it. It is worth reading labels, and worth asking before adding anything aimed at the thyroid.