Selenium; the mineral your thyroid cannot ignore
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Time to read 5 min
Selenium (Se) is an essential trace element that the body cannot produce on its own. You need it, absolutely, but in precise amounts. And most people have less than they should.
Have you felt tired for no reason? Is your hair falling out more than usual? Is your thyroid not working as it should? Before looking for answers elsewhere, it is worth looking at this small but powerful mineral.
Key Fact · Biochemistry
25
distinct selenoproteins in the human body require selenium for their correct synthesis. Without it, none of those proteins can perform their function.
What does selenium do in your body?
Selenium does not act alone; it is incorporated as selenocysteine —the 21st genetically encoded amino acid— within selenoproteins. These proteins are fundamental in processes such as the reduction of oxidative stress, the regulation of the immune system, and the production of active thyroid hormones.
Science-backed benefits of selenium
- High-potency antioxidant: Glutathione peroxidase (GPx), a selenium-dependent enzyme, neutralizes free radicals that damage DNA, cell membranes, and proteins. It is one of the most powerful antioxidant systems in the body.
- Essential thyroid regulator: Iodothyronine deiodinases (DIO1, DIO2, DIO3) are selenoproteins that convert inactive thyroxine (T4) into active triiodothyronine (T3). Without enough selenium, this conversion fails and metabolism slows down.
- Immune system modulator: Selenium boosts T-lymphocyte proliferation and the activity of NK (natural killer) cells, improving the response to viral and bacterial infections.
- Cardiovascular protector: Low levels of selenium are associated with a higher risk of cardiovascular disease. Selenoprotein P acts as a plasma transporter and protector against LDL oxidation.
- Male fertility: Phospholipid hydroperoxide glutathione peroxidase (GPx5) is essential for sperm motility and morphology, being one of the most studied minerals in male reproductive health.
📖 Scientific reference
A meta-analysis published in Thyroid (2018) showed that selenium supplementation significantly reduces anti-TPO antibodies in patients with Hashimoto's thyroiditis, improving thyroid function and the quality of life reported by patients.
Signs you might have a selenium deficiency
Selenium deficiency is more common than you might think, especially in areas with soils poor in this mineral. Many Latin American countries, including Chile, have suboptimal levels in their agricultural soils.
🦋 Hypothyroidism or Hashimoto's
Selenium deficiency promotes the accumulation of H₂O₂ in the thyroid, increasing inflammation and cellular damage.
😴 Chronic fatigue
The reduction in active T3 synthesis slows down cellular metabolism, causing persistent exhaustion.
💇 Hair loss
Uncontrolled oxidative stress affects the hair follicle. Selenium is key in the antioxidation of the scalp.
🧠 Brain fog
The brain is highly dependent on selenoproteins for its protection against neuronal oxidative damage.
🔄 Low immunity
Recurrent infections or slow recovery may be a sign of an immune response compromised by a lack of selenium.
💪 Muscle weakness
Myopathy due to severe selenium deficiency is known as Keshan disease, discovered in deficient areas of China.
Selenium deficiency may not cause symptoms on its own, but it significantly increases susceptibility to diseases caused by other factors, especially in thyroid function.
— Rayman, M.P. (2012). Selenium and human health. The Lancet, 379(9822), 1256–1268.
Selenium and hypothyroidism: the connection many ignore
When we talk about hypothyroidism, iodine often takes center stage. But selenium is equally fundamental. The thyroid gland is the organ with the highest concentration of selenium per gram of tissue in the human body.
60%
of Hashimoto's patients have low selenium levels
Selenium reduces inflammatory markers anti-TPO and anti-Tg, slowing the autoimmune attack on the thyroid and improving general well-being.
Without enough selenium, the H₂O₂ (hydrogen peroxide) generated as a byproduct of hormonal synthesis accumulates, damages thyroid cells, activates the immune response, and accelerates the autoimmune process. The result: hypothyroidism that becomes increasingly difficult to manage with levothyroxine alone.
Liposomal Selenium with Metazome™ patent: the best selenium on the market
Not all selenium supplements are the same. The way the mineral is delivered to the body can make a difference of up to 3 to 5 times in its bioavailability.
Metazome™ technology is a patented dry liposome system that encapsulates selenium in phospholipid vesicles—the same structures that form our cell membranes—allowing the mineral to be recognized by the body as "its own" and absorbed efficiently and directly.
Why is liposomal selenium absorbed better?
🔬
Dry liposomes
Solid-state technology. Greater stability and shelf life than conventional liquid liposomes.
🧬
Phospholipid membrane
Identical in structure to the membrane of your cells. The body absorbs it as a priority.
🎯
Direct cellular delivery
Selenium reaches cells directly without being degraded in the digestive tract.
⚗️
International patent
Metazome™ has clinical support and comparative bioavailability studies.
Conventional Selenium vs. Metazome™ Liposomal Selenium
Conventional selenium
~30%
estimated actual bioavailability
Metazome™ Liposomal Selenium
~90%
absorption boosted by liposomes
* Indicative percentages based on bioavailability studies of liposomal formulations.
The advantage of the dry liposome
Most liposomal products on the market are liquid: they are unstable and degrade with time, temperature, or oxidation. Metazome™ dry liposome technology solves this by encapsulating the vesicles in a solid format, maintaining their integrity until the exact moment of absorption in your body.
How much selenium do you need daily?
The recommended daily intake (RDI) varies by life stage:
👶 Children (1–8 years)
20–30 mcg/day (NIH, 2022)
🧑 Adults
55 mcg/day. Optimal functional level: 70–100 mcg/day
🤰 Pregnancy / Lactation
60–70 mcg/day. Critical for the baby's thyroid development.
⚠️ Tolerable upper limit
200 mcg/day in adults according to the Ministry of Health. Exceeding that level can cause selenosis.
💡 Professional advice
If you have hypothyroidism, Hashimoto's, or simply want to optimize your thyroid function and antioxidant system, consult your doctor or nutritionist about whether liposomal selenium can be part of your protocol. Precision supplementation always starts with an individual assessment.
✍️ Author
Nelba Villagrán
Integrative Orthomolecular Nutritionist | Technical Manager
Who is Nelba Villagrán? →
Frequently asked questions about selenium
Does selenium cure hypothyroidism?
No, selenium is not a treatment for hypothyroidism. However, in people with Hashimoto's thyroiditis, selenium supplementation has been shown to reduce anti-TPO antibodies and improve general well-being. Always as a complement to established medical treatment.
Can selenium be taken together with levothyroxine?
Generally yes, but always under medical supervision. It is recommended to take levothyroxine on an empty stomach and leave a margin of 2–4 hours before taking any mineral supplement.
Why choose liposomal selenium and not conventional selenium?
The difference is in actual absorption. A supplement with high bioavailability (like the one with Metazome™) ensures that the mineral effectively reaches your cells, rather than simply passing through the digestive system without being correctly absorbed.
What is Metazome™ dry liposome technology?
Metazome™ is a patented solid-phase liposomal encapsulation. Unlike conventional liquid liposomes that degrade with time and temperature, dry liposomes maintain their structural integrity until the moment of absorption, ensuring maximum efficacy.
Does liposomal selenium have side effects?
At correct doses, liposomal selenium is safe and well tolerated. Liposomal technology also reduces the gastrointestinal irritation that some inorganic forms of the mineral can cause. It is recommended not to exceed 400 mcg/day in adults.
