Hashimoto’s: what to do when your thyroid antibodies are raised

The short answer

Raised thyroid peroxidase (TPO) antibodies suggest your immune system is reacting against your thyroid. This can happen years before thyroid hormone levels fall. From a functional medicine perspective, this is an opportunity to investigate the wider picture: nutrient status, gut health, diet, stress and other factors that may be contributing to your symptoms and immune health.

“Your antibodies are high, but your thyroid is working, so we’ll just keep an eye on it.”

I hear this often. Monitoring matters, but it can leave you feeling that you have to wait until your thyroid struggles before anything can be done.

In my clinic, raised antibodies prompt a broader conversation. How are you feeling? What changed before your symptoms began? Are you absorbing nutrients well? How are your digestion, sleep and energy? Is there a family history of autoimmunity?

You may not need thyroid medication yet, but there is still plenty worth investigating and supporting.

What are thyroid antibodies?

Antibodies are proteins produced by the immune system. In autoimmune thyroid disease, the immune system loses tolerance to parts of the thyroid and develops a response against them.

The main antibodies are:

Antibody	Usually raised in	What it means
TPO antibodies (TPOAb)	Hashimoto’s, sometimes Graves’ disease	A common marker of thyroid autoimmunity
Thyroglobulin antibodies (TgAb)	Hashimoto’s and other autoimmune thyroid conditions	Another marker that can help identify thyroid autoimmunity
TSH receptor antibodies (TRAb)	Graves’ disease	Can stimulate the thyroid to produce excess hormone

Antibodies help us understand the underlying process, but their level does not directly measure how much damage has occurred or how unwell you should feel. A positive result needs to be interpreted alongside your thyroid function, symptoms and history.

What is Hashimoto’s?

Hashimoto’s is an autoimmune condition affecting the thyroid. Over time, the immune response can damage thyroid tissue and reduce its ability to produce hormones.

From a functional medicine perspective, we consider both thyroid function and the wider immune picture. Replacing missing hormone can be essential, while nutrition, digestion and lifestyle may need attention too.

Hashimoto’s can be present while TSH and free T4 remain within their reference ranges. This gives us a valuable opportunity to assess your health before an underactive thyroid develops.

Symptoms associated with an underactive thyroid include:

tiredness and reduced stamina
feeling unusually cold
constipation and weight gain
brain fog and difficulty concentrating
low mood
dry skin, hair thinning or hair loss
a hoarse voice
heavy or irregular periods

These symptoms deserve investigation, even when an initial thyroid result is described as normal. Some may relate to thyroid function; others may reflect overlapping issues such as iron deficiency, poor sleep or hormonal changes.

Do raised antibodies mean I need levothyroxine?

Raised antibodies alone do not mean you need thyroid hormone replacement. That decision depends on thyroid function, symptoms and circumstances, including pregnancy.

If your thyroid is becoming underactive, levothyroxine can provide the hormone your body needs. Supporting immune health and replacing missing thyroid hormone can sit alongside each other.

In practice, I look at the pattern over time. Is TSH rising? Is free T4 falling? Are symptoms changing? A result within the laboratory range is useful information, but it does not explain every aspect of how you feel.

My aim is to understand that fuller picture and identify what we can reasonably improve.

How should Hashimoto’s be monitored?

Monitoring should bring together blood results and your experience of daily life.

TSH and free T4 remain central. Depending on the clinical picture, I may also include free T3 to add context, alongside nutrients such as iron, B12 and vitamin D. Free T3 alone cannot tell us how well every tissue is using thyroid hormone.

Routine repeat antibody testing is not performed on the NHS because it rarely changes treatment but in Functional medicine antibody testing can be very valuable.

I also want to know whether your energy, digestion, concentration, temperature tolerance and menstrual health are improving.

You can read more in Is TSH enough?

What can I do if my thyroid antibodies are raised?

There is no single trigger or universal Hashimoto’s protocol. My approach is to identify the factors relevant to you and build a manageable plan.

Nutrients the thyroid relies on. Iron, selenium, zinc and iodine contribute to thyroid hormone production or metabolism. Vitamin D and B12 may also be relevant to your wider health and symptoms. I look at dietary intake, absorption and appropriate testing before recommending supplements. More is not always better, particularly with iodine and selenium.

Gut health and absorption. Persistent bloating, constipation, diarrhoea or food reactions deserve attention. These can affect nutritional status and quality of life. Depending on your history, we may investigate coeliac disease, digestive problems or other gut conditions. Microbiome testing can sometimes add information, but it is not automatically necessary for everyone with Hashimoto’s.

Gluten and individual food responses. Coeliac disease is more common in autoimmune thyroid disease, and testing is recommended at diagnosis. Arrange testing while you are still eating gluten. Beyond coeliac disease, I may explore a structured dietary trial where symptoms suggest it could help, with a clear plan to assess the response. Gluten exclusion is not a proven treatment for everyone with Hashimoto’s.

Blood sugar and adequate nourishment. Regular meals, sufficient protein, fibre and a varied diet provide a practical foundation. I also look for under-eating, restrictive diets or repeated energy crashes. Supporting your thyroid should include giving your body enough fuel.

Stress, sleep and recovery. I ask about sleep quality, workload, emotional strain and whether you have any space to recover. These factors can have a substantial effect on energy and wellbeing. We build realistic support around your life, rather than adding another demanding list of things to do.

Hormonal transitions. Pregnancy, the postpartum period and perimenopause can bring changes in symptoms and thyroid requirements. Looking at the timeline helps us understand what needs checking and how closely to monitor.

Other relevant contributors. Your medical history, medicines, supplements and other autoimmune conditions may provide useful clues. Further testing should follow those clues, with a clear purpose.

Selenium is one supplement studied in Hashimoto’s. A 2024 review found reductions in TPO antibodies, but this does not establish that supplementation prevents thyroid damage or removes the need for medication. I consider intake, likely need and dose rather than recommending it routinely.

Is it thyroid, or something else?

It can be several things at once.

Someone with Hashimoto’s may also have low iron stores, disturbed sleep, digestive problems or perimenopausal changes. Addressing these can make a meaningful difference, even when thyroid medication is already well adjusted.

This is where a functional medicine assessment can be helpful: bringing the pieces together and deciding which deserve attention first.

See Thyroid or perimenopause? How to tell the difference and my thyroid guide.

When to see your GP

Arrange a thyroid review if symptoms are developing or worsening, or if you notice swelling in your neck.

If you are pregnant or planning a pregnancy, let your GP or maternity team know about your thyroid antibodies so testing and treatment can be reviewed early.

Difficulty breathing or significant difficulty swallowing requires urgent medical assessment.

Common questions

Can thyroid antibodies go down?

Yes, antibody levels can fluctuate and sometimes fall. Certain interventions, including selenium in some studies, have reduced TPO antibodies. However, a reduction does not reliably tell us whether symptoms will improve or future hypothyroidism will be prevented.

My focus is on supporting your health, correcting identified problems and monitoring thyroid function—not chasing an antibody number alone.

Will I definitely develop an underactive thyroid?

No. Raised antibodies increase the likelihood, but progression is not inevitable. Regular thyroid function checks help identify changes early.

Meanwhile, we can work on your nutrition, digestion, sleep and any other problems identified in your assessment.

Should I go gluten-free if I have Hashimoto’s?

If you have coeliac disease, strict gluten avoidance is essential.

If you do not, the evidence is mixed. Get tested for coeliac disease while you’re still eating gluten, then decide with your practitioner.