Is it good to take selenium for hypothyroidism?

A brown plate with cut lemon, meat and greens on the wooden table.

You know that when I was writing this article I got a bit surprised. I’d say, at this negative meaning. Every time I write somethings, besides normal science researcher I’m checking what people are looking for regarding their condition.

What was the surprise is that some of the most typed questions or phrases were like this:

  • Is selenium good for thyroid?
  • What is selenium?
  • What is hypothyroidism?
  • can selenium help thyroid function?

We completely lack basic knowledge about health. That’s a fault of our schools and medical specialists that doesn’t educate patients about the disease they got diagnosed with. Here you’ll find out how selenium helps thyroid, what selenium does to the thyroid gland.

Like vitamin D, you have to have enough selenium in your body to treat Hashimoto hypothyroidism.


  • You should take selenium for hypothyroidism if you have a deficiency,
  • Selenium plasma concentration is often low in hypothyroid Hashimoto patients,
  • Normal selenium plasma range is 60 – 120 microgram per liter, it is good if your level is in higher-normal range,
  • Selenium plays a key role in thyroid gland protection from oxidative and autoimmune-mediated destruction,
  • Selenium low status or deficiency is related to a disturbance in thyroid function as well as pathological conditions autoimmune hypothyroidism, subclinical hypothyroidism, and enlarged thyroid gland,
  • Selenium supplementations, especially with organic forms (selenomethionine, selenocysteine) usually improves thyroid function and alleviates autoimmunity.

You should already have known that Vitamin D is one of the most essential nutrients in Hashimoto’s Disease (HT) like in other autoimmune diseases. Selenium is another one without which thyroid can’t work properly, and… safely. Moreover, both nutrients support their function especially selenium potentiates thyroid-healthy properties of vitamin D.

READ: Vitamin D Supplementation can help you treat Hashimoto’s Thyroiditis

If you haven’t read an article about the importance of vitamin D in HT I’d recommend you read it first, then go back to this one. You’ll keep things going in an order to understand them best by that.

Selenium for thyroid?

In contrast to vitamin D function, which stimulates gene expressions which means protein production – selenium is an essential part of some of them which are called selenoproteins.

Some of them are actively protecting the thyroid gland from oxidative damage by oxidants. The latter is naturally produced in the body during the processing of food nutrients in the cell to generate usable energy from them.

Selenium protects the thyroid gland from destruction

In the thyroid gland, selenoprotein called glutathione peroxidase protects the gland against hydrogen peroxide generated for iodide oxidation during the production of thyroid hormones.

Oxidation of iodide is necessary to produce thyroid hormones and in the case of selenium depletion, oxidants that are not used in this process interact in thyroid gland molecules destroying them. That is why selenium deficiency is a risk factor for developing Hashimoto’s Disease.

From the other side, iodine overconsumption from the diet or worse from supplements is a risk factor of HT development. One of the reasons for that is increased oxidant production and thus, potential thyroid gland destruction.

This stimulates the immune system and may cause inflammation and autoimmune processes. If you are taking any dietary supplements you should really be careful about iodine content in them.

Selenium regulates thyroid hormones activity

Another role that selenium (Se) does is being a part of another selenoprotein called iodothyronine deiodinases. Those are responsible for homeostasis of thyroid hormones making them active or inactive.

In the case of Se deficiency, you may have increased inactive thyroid hormones (T4 and fT4) and decreased active ones (T3). That is what you don’t want, that is what hypothyroidism is.

Increase selenium intake from diet

Selenium-containing food products are widely eaten although there are still many places in the world deficient in this compound. For example, the daily intake of Se in Europe is approximately about 40 micrograms per day (which is 0,000 04g).

Scientific Committee on Food of the European Commission recommends a daily intake of 55 micrograms of Se per day. This means that Europeans are eating 15 micrograms Se less than they should be providing 72% of the amount they need.

Despite that those amounts are extremely low, they are extremely important for the immune system and thyroid gland function.

You can find selenium at animal food products like fishes like salmon (it has omega-3 too!), tuna, halibut and sardines (they are also a good source of collagen), white meat like chicken or turkey and grass-fed beef, offals like liver and kidney, eggs and cheese. Brazil nuts are the richest selenium-containing food products, besides them, in plant food products you’ll find selenium in oats (great source of beta-glucan type plant fiber), mushrooms (especially sundried are a great source of vitamin D too), seeds like sunflower seeds, bread.

Selenium thus plays two essential roles, it protects the thyroid gland from reactive oxidants that are essential for thyroid hormones production and secondly is a part of proteins that metabolizes those hormones.

Infographic. Selenium and thyroid function. Selenium is a key player for antioxidative protection of the thyroid gland. It regulates thyroid hormones activity. Alleviates inflammatory processes and improves vitamin D functions.

Selenium and thyroid function.

Serum selenium concentration

Se deficiency is often a case in HT but it is easily manageable by supplementation or diet. You can test your selenium serum concentration and check out if it is in an appropriate concentration.

The standard Se level ranges from 60 to 120 micrograms per liter. Unfortunately, it doesn’t reflect thyroid gland saturation and that is what we are unable to test. However, studies on HT patients confirms that its good to provide high enough of Se from the diet.

Even if you have tested yourself and found having low Se status, Se supplementation or increase of Se serum concentration doesn’t have to bring any clinical improvements. Don’t worry, it is still a good step forward for you if you have HT.

Sometimes lack of results only shows how interconnected and complex are metabolic processes in the body. Selenium no matter how much you’d like it to be it’s not a miracle for your inflamed autoimmune thyroid. You should do more effort than just taking a simple pill.

Note that in one study long-term Se intake by 8 years almost tripled the risk of developing type 2 diabetes. Both low and high selenium concentration in the blood is dangerous to the body.

Selenium and Hashimoto’s Disease

Selenium nourishment is believed to be responsible for positive changes in the echostructure of the thyroid gland in HT patients. It is possible, that this effect is a result of alleviation:

  • Inflammatory processes,
  • Antioxidative protection.

Another important antioxidant in your body is glutathione. It is naturally synthesized in the body and often reported to be decreased in HT patients. If you haven’t heard about glutathione, check out what it is and how to increase its production in the body.

READ Glutathione – Boost Your Natural Protector 

If you want to increase Se status in your body you want to choose organic compounds like selenomethionine or selenocysteine instead of inorganic ones like selenite and selenate. The former ones have a better absorption rate in the gut thus their bioavailability for the body is higher.

Inorganic Se compounds used in the studies on HT patients might be responsible for a lack of results reported in some of them. 

An organic form like selenomethionine was reported to block the production of inflammatory compounds that directly lead to thyroid destruction or blocks their function. You should know that even if your thyroid gland looks good at the scan and has proper volume. It may be blocked by inflammatory processes that are going inside there.

How is that happening? By blockage of thyroid-specific protein synthesis by inflammatory cytokines. Selenium depletion aid to that. Moreover, when you are lacking Se, oxidative stress increases and this leads to stimulation of anti-thyroid antibody production.

Antithyroid antibodies like thyroid peroxidase antibody (anti-TPO) and thyroglobulin antibody (anti-TG) are mediating autoimmune thyroid destruction. Their serum concentration, especially anti-TPO are directly related to clinical complications in autoimmune hypothyroidism.

Selenium supplementation in Hashimoto’s Disease

If you are hypothyroid, have decreased thyroid function or contrary – increased thyroid volume, multiple nodules you can expect yourself to be selenium deficient. If you tested yourself and that is the case, I’d recommend taking 200 micrograms of selenomethionine for 6 or 12 months and retest.

Note that plasma Se concentration of 60 to 120 micrograms per liter is in the normal range, although studies show that it’s better to be at higher-normal range. But definitely stop supplementation if you go above the normal range.

Based on currently done studies so far, anti-TPO titers seems to be easier decreased by Se nourishment than anti-TG. Anti-TPO might decrease in 6 months while anti-TG after 12 months of intervention.

Are selenium supplements intake safe?

In one study long-term selenium supplementation increased risk of cancer and type 2 diabetes. Because of the lack of studies, it is hard to tell how long and what dose is safe. However, it is known that you shouldn’t go above 200 micrograms of selenium in the plasma.

Some patients, especially when taking the inorganic form of selenium (selenite, selenite) reports mild gastric discomfort and pain. But it is rare. Remember that organic form is a better choice for absorption and for your guts if they are sensitive.

Some scientists discourage Se supplementation in HT patients if their Se status is in the normal range because of possible hypothyroidism exacerbation and other disease development. As usual, we need more studies to make firm conclusions.

However, those studies done so far put selenium in a good light. Talk with your dietitian or doctor and make your decision.


Selenium supplementation is often a good choice in Hashimoto’s patients because of undernourishment. This mineral plays a key role in thyroid gland protection from the destruction and thyroid hormones metabolism. Although plasma selenium concentration above normal range might exacerbate hypothyroidism or increase the risk of developing other diseases – current studies show that Hashimoto’s patients may benefit a lot from selenium supplementation. An organic form has a higher bioavailability than inorganic ones. By improving selenium status in the body you may decrease anti-thyroid antibody titers and alleviate hypothyroidism.

Sources & References

All references can be found in the original article published in Journal of Food and Nutrition Research “Supplementation in Autoimmune Thyroid Hashimoto’s Disease. Vitamin D and Selenium (DOI: 10.12691/jfnr-7-8-6).