Functional Medicine · Hormonal Health

The Journal

by Dr. Natasha Ryan, ND

Thyroid · Autoimmunity

Hashimoto's With a Normal TSH: What Thyroid Antibodies Mean and What Helps

5 min read

You finally got someone to run more than a TSH. It came back normal, but the thyroid antibodies didn't. Your TPO antibodies are high. Someone tells you it's Hashimoto's, but there's nothing to treat until your TSH goes up.

So you wait. And you keep feeling tired, foggy, cold, and puffy, with hair in the drain.

Here's what positive antibodies with a normal TSH actually mean, and what you can do while you wait.

What the antibodies tell you

Hashimoto's thyroiditis is an autoimmune condition. Your immune system makes antibodies against your own thyroid, and over time the inflammation can damage the gland so it makes less hormone.

The two antibodies tested are:

  • TPO antibodies (thyroid peroxidase), the most common marker of Hashimoto's
  • Thyroglobulin antibodies (TgAb), positive in many but not all cases

Having positive antibodies means the autoimmune process is there. It doesn't mean your thyroid has stopped working yet. TSH only rises once the gland is struggling to keep up.

How common it is

Thyroid antibodies are surprisingly common. In the large US NHANES III survey, about 11% of people with no known thyroid disease had positive TPO antibodies, and about 10% had positive thyroglobulin antibodies. Both were more common in women than men.

Will it turn into hypothyroidism?

Not always, but the risk is real. The best long-term data comes from the Whickham Survey, which followed people in northern England for 20 years.

Compared with women who had neither, women who started with:

  • Positive antibodies alone had about 8 times the odds of developing hypothyroidism
  • A raised TSH alone had about 8 times the odds
  • Both positive antibodies and a raised TSH had about 38 times the odds

So antibodies are an early warning. They tell you to monitor, not to panic.

Why you might feel unwell with a normal TSH

This is the frustrating part. Many women with Hashimoto's feel tired, foggy, achy, and low even when their TSH is in range.

A 2019 randomized trial in the Annals of Internal Medicine took this seriously. Researchers in Norway studied people with Hashimoto's who had persistent symptoms despite normal thyroid hormone levels on treatment, and very high TPO antibodies. Those who had their thyroid removed reported large improvements in quality of life and fatigue over 18 months. Those who stayed on medication alone did not improve.

Surgery isn't the takeaway here. The study was small, the patients had unusually high antibody levels, and surgery has real risks. But it supports something many women already know: the autoimmune process itself may cause symptoms, separate from thyroid hormone levels.

There are other reasons too. A TSH in the "normal" range may not be normal for you, and TSH alone doesn't show how much active hormone (free T3) you're making. See Is It Your Thyroid or Your Hormones? and "Your Labs Are Normal".

The labs worth tracking

If you have positive antibodies, a fuller thyroid picture helps:

  • TSH
  • Free T4 and free T3
  • TPO and thyroglobulin antibodies
  • Ferritin, vitamin D, and B12, which affect thyroid function and energy
  • A celiac screen (tissue transglutaminase IgA, with total IgA)

Most guidance suggests rechecking TSH about once a year when antibodies are positive and TSH is normal, or sooner if symptoms change. Many functional medicine doctors check more often while making changes.

What helps

Selenium

The thyroid has more selenium per gram than any other organ, and it's needed both to make thyroid hormone and to protect the gland from damage.

A meta-analysis of 35 randomized trials found selenium lowered TPO antibodies, and lowered TSH in people not taking thyroid medication. It didn't change thyroglobulin antibodies, and side effects were no different from placebo. Most trials used around 200 mcg a day.

What we don't know yet is whether lowering antibodies prevents hypothyroidism down the line. And more isn't better. Selenium becomes toxic at high doses, so don't combine several supplements that each contain it. Selenium is available through my Fullscript dispensary, and two or three Brazil nuts a day is a food-based option.

Celiac screening, then a thoughtful look at gluten

Celiac disease is more common in people with autoimmune thyroid disease. A 2016 meta-analysis of 27 studies found biopsy-confirmed celiac disease in 1.6%, or about 1 in 62, and the authors recommended screening everyone with autoimmune thyroid disease.

For women who don't have celiac disease, the evidence is less clear. A 2025 meta-analysis of three small trials found a gluten-free diet lowered thyroglobulin antibodies, but TPO antibodies actually rose and TSH didn't change. The certainty was very low.

So screen first. If you don't have celiac disease and want to try going gluten-free, treat it as a three-month experiment and track how you feel and what your labs do.

The basics that calm autoimmunity

  • Sleep and stress. Chronic stress affects immune balance. See Nervous System Regulation and Hormones.
  • Gut health. Much of your immune system sits in the gut lining.
  • Vitamin D and iron, brought into a healthy range if they're low.
  • Protein and enough food. Under-eating slows thyroid conversion.

When medication makes sense

Once TSH rises, thyroid hormone replacement is the standard treatment. Some women with positive antibodies, ongoing symptoms, and a TSH in the upper part of the normal range may be offered treatment earlier. That's a decision to make with your clinician.

Hashimoto's in midlife

Perimenopause and Hashimoto's share many symptoms: fatigue, weight gain, low mood, poor sleep, hair thinning, and brain fog. They also often show up at the same age. If you're in your 40s with these symptoms, it's worth checking both rather than assuming it's one or the other.

What you can do now

  1. Get the full panel, including free T3, free T4, and both antibodies.
  2. Ask for a celiac screen.
  3. Check selenium-containing supplements you already take before adding more.
  4. Recheck at least yearly, or sooner if symptoms change.

Positive antibodies with a normal TSH aren't a reason to do nothing. They're an early signal, and a chance to act before the thyroid is damaged.

References

  1. Hollowell JG, et al. Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab. 2002. View source
  2. Vanderpump MP, et al. The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey. Clin Endocrinol. 1995. View source
  3. Guldvog I, et al. Thyroidectomy versus medical management for euthyroid patients with Hashimoto disease and persisting symptoms: a randomized trial. Ann Intern Med. 2019. Summary in Clinical Thyroidology for the Public, American Thyroid Association. View source
  4. Selenium supplementation in patients with Hashimoto thyroiditis: a systematic review and meta-analysis of randomized clinical trials. 2024. View source
  5. Roy A, Laszkowska M, Sundström J, et al. Prevalence of celiac disease in patients with autoimmune thyroid disease: a meta-analysis. Thyroid. 2016;26(7):880-890. View source
  6. Araújo EMQ, Coutinho-Lima CRO, de Sousa AS, et al. Effects of gluten-free diet in non-celiac Hashimoto's thyroiditis: a systematic review and meta-analysis. Nutrients. 2025;17(21). View source