Your whole body thrives when it has enough iodine. The benefits extend way beyond the thyroid gland. As we talked about in a recent article about iodine’s benefits beyond the thyroid, we saw:
- Iodine helps support the immune system in fighting infections.
- Iodine regulates estrogen and supports reproductive health.
- Iodine helps keep blood pressure and cholesterol at normal levels.
- Iodine improves insulin sensitivity.
- Iodine helps remove toxins like heavy metals, fluoride, and bromide.
- Iodine helps keep women’s breast tissue normal so they don’t get fibrocystic breast disease.
- Iodine helps keep the heart rhythm normal as well.
- Iodine helps keep blood sugar at the normal level.
- Iodine is critical during pregnancy for brain development and IQ.
We even saw there’s a few signs of iodine deficiency:
- fibrocystic breast disease
- polycystic ovary syndrome (PCOS)
- irregular heartbeat
- infertility
- poor concentration
- poor detoxification
Indeed, iodine has some very amazing benefits. However, when you take high doses of iodine as supplemental iodine, it’s very important to also get adequate amounts of selenium also to protect the thyroid and maximize these benefits.
When you take high doses of iodine as supplemental iodine, it’s very important to also get adequate amounts of selenium also to protect the thyroid
Here’s Why You Need Selenium To Help Protect The Thyroid.
The thyroid gland is where thyroid hormone is created. It converts iodine into thyroid hormones like thyroxine, T4, and triiodothyronine, T3. (Most of the T3 is made outside of the thyroid, but about 20% is made in the thyroid.) This process generates a lot of free radicals and oxidative stress that needs to be suppressed before it damages the thyroid cells. This is why you need selenium.
The trace mineral selenium acts as a cofactor for some key enzymes, especially glutathione peroxidase (GPx). Glutathione peroxidase neutralizes harmful hydrogen peroxide and other free radicals that are made during the thyroid hormone production. If you don’t have enough selenium, the thyroid can become vulnerable to inflammation, impaired function, and autoimmunity.
Selenium and iodine work hand in hand. Selenium deficiency can make the impact of iodine’s insufficiency much worse. There are cases of double deficiency of selenium and iodine leading to a condition called myxedematous cretinism. To combat the formation of cretinism, you need both selenium and iodine in sufficient quantities.
Several studies highlight that maintaining optimal selenium levels helps safeguard the thyroid.
Evidence from Research: Selenium’s Protective Benefits
In a 2017 review by Ventura, Melo and Carillo, they said, “The literature suggests that selenium supplementation of patients with autoimmune thyroiditis is associated with reduction in antithyroperoxidase antibody levels, improved thyroid ultrasound features, and improved quality of life.” So if someone has high levels of autoimmune antibodies against thyroid proteins, having sufficient amounts of selenium can be very helpful.
A study in New Zealand looked at people between the age of 60 and 80 who had mild selenium and iodine deficiencies. In this controlled study, giving selenium or selenium plus iodine improved glutathione peroxidase activity and improved iodine status as well, compared to the placebo group. Thyroglobulin concentration decreased as a result, which is a sign of alleviated thyroid strain. Overall, they found that selenium did boost antioxidant defenses, without harming thyroid hormone production.
In a clinical trial of pregnant women, 77 thyroid peroxidase antibody- positive (TPOAb(+)) women received 200 micrograms of selenomethionine a day. In another 74 TPOAb(+) women, a placebo was administered. And then 81 TPO antibody negative age-matched women were the control group.
They looked at postpartum thyroid dysfunction in these pregnant women and found that the ones that took selenium had significantly lower levels of PPTD (28.6 vs 48.6% of the women) and permanent hypothyroidism (11.7 vs 20.3%). So, it made quite a big difference, almost cutting the risk in half, taking just 200 micrograms of selenium a day.
A large cross-sectional observation study in China pointed out the differences in thyroid function in 2 counties—one that was selenium deficient and another county that was selenium adequate. They looked at serum samples for thyroid function and selenium concentrations.
For this group of 6,152 participants, they found that the prevalence of pathological thyroid conditions was significantly lower in adequate selenium county (18.0%) compared to the low selenium county (30.5%). Higher serum selenium was associated with lower odds of autoimmune thyroiditis, subclinical hypothyroidism, hypothyroidism, and enlarged thyroid. Having enough selenium really makes a difference for the thyroid.
Recommended Dosage and How to Incorporate Selenium
So if you are supplementing your diet with iodine, with Nascent Iodine or equivalent, it’s a good idea to take about 200 micrograms of selenium a day. This helps support thyroid health and prevents potential imbalances. Long-term use of 200 micrograms a day is really considered safe. The upper safety limit of selenium is 400 micrograms a day. Using the selenomethionine form of selenium (the most common form found in dietary supplements) is much safer than selenium as sodium selenite.
Of course, if you are seeing a doctor for thyroid issues, you should consult with him about taking selenium and iodine.
At Hallelujah Diet, we recommend our Glutathione Promoter / Selenium supplement to complement iodine intake. This formula provides selenium in its most bioavailable form (selenomethione), along with supportive ingredients like N-acetyl L-cysteine (a glutathione precursor and direct antioxidant), alpha lipoic acid (for water- and fat-soluble protection), zinc, vitamin C, and vitamin E. Together, these promote glutathione production—the body’s master antioxidant—while enhancing immune function and protecting against oxidative stress from infections or hormone synthesis. It’s non-GMO, vegetarian, and easy to digest, even on an empty stomach. You can find it here, and customer reviews rave about its role in maintaining health and vitality. A high-quality multivitamin, multimineral supplement often includes selenium, so if you are taking one of those, check the label to see if you’re covered.
Final Thoughts
Combining selenium supplementation with iodine is a great idea. It’s a smart strategy for protecting your thyroid and getting full benefit out of iodine’s potential for energy, immunity, hormone balance and more.
Selenium helps support glutathione peroxidase function to suppress any oxidative damage in the thyroid. Basically, it makes sure your thyroid operates smoothly when you have a lot of extra iodine running around.
So get them both: iodine and selenium for your best chances of improving thyroid health.
