How Much Selenium Per Day For Immunity

  • By Performance Lab
  • 5 minute read
How Much Selenium Per Day For Immunity

We’re always looking for ways to optimize body performance and keep ourselves as healthy as possible, and doing that starts with supporting immune function.

It’s a system that keeps you protected from invading pathogens that can compromise health and performance, but it’s also one of the hardest hit where diet and lifestyle choices are concerned.

Aren’t getting enough sleep? Not eating properly? Stressed out?

Unfortunately, they all contribute to a weakened immune system. And although selenium is a trace mineral that’s only required in small amounts, when it comes to supporting immune function, this guy is big.

We’re talking about the role of selenium in immunity and how much you should be getting for optimal performance.

What Is Selenium?

In the spectrum of vitamins and minerals, we have certain ones that the body requires in larger amounts for optimal function. Trace elements, like selenium, are minerals that are present in living tissues in small amounts that function primarily as catalysts in enzyme systems 1.

However, unlike water-soluble vitamins, all trace elements are toxic when consumed in high levels for extended periods; the difference between toxic intakes and optimal intakes for physiological demands of essential trace elements differs between elements.

But what exactly is selenium?

It wasn’t until the 1950s that the importance of selenium was recognized. Extreme differences in exposure were found across the world, even within countries, which enables the understanding of the correlation between selenium deficiency and human disease prevalence.

While the entire scope of roles for selenium isn’t well known or understood, the only major biochemical function recognized for selenium in all mammals is its role in the peroxide-destroying enzyme glutathione peroxidase 1.

It may also participate in other important metabolic interactions with a number of hazardous elements, including mercury, cadmium, and arsenic.

The Role Of Selenium In Immune Function

In humans, the primary role of selenium is attributed to the function of 25 selenoproteins that have selenocysteine at their active center 2.

The family of glutathione peroxides exhibit the most far-reaching effects; they are a group of antioxidant enzymes that remove hydrogen peroxide, lipid hydroperoxides, and (GPx4) phospholipid and cholesterol hydroperoxides.

Individually, they all exert specific roles, such as 2:

  • GPx1 (cystolic): Reduces retroviral virulence by preventing viral mutations
  • GPx2 (gastrointestinal): Antiapoptotic function in the colon; helps to maintain the integrity of intestinal mucosa
  • GPx3 (plasma): Antioxidant in extracellular fluids; protects the thyroid from hydrogen peroxide in thyrocytes and follicular lumen
  • GPx4 (phospholipid): Membrane-associated; present in high concentrations in the testis, where it’s required for sperm motility and viability

When we dive into this further, we can see that selenium plays an important role in mitigating oxidative stress, which is linked to high levels of inflammation, immune responses, and disease.

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Selenium supplementation has been shown to exhibit immunostimulant effects, such as enhancing the proliferation of activated T cells, increasing cytotoxic lymphocyte-mediated tumor cytotoxicity, and natural killer cell activity 2.

One study of elderly volunteers found that supplementation with 400 μg of selenium per day significantly increased total T-cell count by more than 27% compared to the placebo, which was attributed to an increase in subsets of CD4+ T cells and increased cytotoxicity of natural killer cells 3.

The reason selenium is linked to a stronger immune response is because selenoproteins are essential for activated T-cell function.

And because T cells are especially sensitive to levels of oxidative stress, selenoprotein-deficient T cells cannot proliferate in response to T-cell-receptor stimulation because of the inability to suppress the production of reactive oxygen species (free radicals) 4.

Rodent studies find that mice with selenoprotein-less T-cells exhibit reduced pools of mature and functional T-cells in lymphoid tissues along with impaired T-cell-dependent antibody responses.

Long story short, the biological effects of selenium are mainly seen through its incorporation into selenoproteins, and selenoproteins are heavily involved in the activation, proliferation, and differentiation of cells that drive both innate and adaptive immune responses 5.

Thus, sufficient intake of selenium through diet and selenoproteins is not only important for initiating or enhancing immune function, but they’re also involved in immunoregulation, which is essential for preventing excessive immune responses that can contribute to the development of autoimmunity or chronic inflammation.

Interestingly, in low selenium supply, synthesis of some selenoproteins—for example, glutathione peroxidase, GPx4—is prioritized over others 2.

The importance of selenoproteins and the associated enzymes to human health is evident by looking at the effects of single nucleotide polymorphisms (SNPs) in selenoprotein genes on disease risk or mortality—CVD, cancer, stroke, type 2 diabetes, metabolic syndrome, and more.

Selenium Deficiency

As we just mentioned, the thing with selenium is that tissues that maintain high concentrations of selenium will maintain their selenium levels during deficiency, but tissues such as those of the immune system will exhibit a more rapid decline in bioavailable selenium during deficiency, ultimately resulting in decreased synthesis of selenoproteins 5. Researchers refer to this as “the hierarchy of selenoprotein synthesis.”

But what happens when you don’t get enough selenium?

More than 500 million people are affected by selenium deficiency around the world due to inadequate intake, especially where soil concentrations are low, which affects the quantities present in food 6.

Under normal conditions, selenium acts in combination with vitamin E to maintain the integrity of cell membranes, participating in redox reactions with hydrogen peroxide-producing glutathione.

A deficiency of this critical mineral exacerbates the redox by-product toxicity and oxidative damage to cell membranes 6. A deficiency of selenium has also been shown to turn harmless viruses into virulent pathogens.

Other effects of selenium deficiency include:

  • Infertility
  • Thyroid dysfunction
  • Muscle weakness
  • Fatigue
  • Brain fog
  • Hair loss
  • Weakened immunity

How Much Selenium For Immunity?

Selenium is widely available in food sources that are both animal and plant-based. While selenium is present in plant food in organic form as selenomethionine with about a 90% bioavailability, inorganic forms like selenate and selenite are also used in supplements and are highly bioavailable.

Studies consistently suggest that adequate dietary selenium is essential for the activity of virtually all arms of the immune system, and if not getting adequate intake from diet, supplemental selenium can also improve immune function.

Currently, the recommended dietary intake (RDI) for selenium is 55mcg with a tolerable upper intake level of 400mcg per day 7.

Levels above this are considered to be toxic. Because high levels of selenium can be problematic, sticking to the recommended daily intake is ideal.

However, some studies suggest the RDI is on the low side and set the minimum requirement at 90 mcg daily per adult.

But if you’re looking for the ultimate way to boost immune function, Performance Lab PL-Immune has you covered.

It’s the most comprehensive dynamic immune support supplement on the market designed to activate immune cells and support all types of immune responses. With each serving you’re getting:

  • 25mcg NutriGenesis Vitamin D
  • 30mg NutriGenesis Vitamin C
  • 25mcg NutriGenesis Selenium
  • 5mg NutriGenesis Zinc
  • 50mg IMMUSE Paraprobiotic
  • 250mg Setria Glutathione
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Final Thoughts

Supporting your immune system in a world that seems to always be working against it can be challenging, but if you know what your body needs for optimal function, it’s a cinch.

While adding selenium into your diet can make a big impact for the immune system, giving it a bigger boost with PL-Immune containing selenium and five other powerful immune-boosters is a surefire way to keep you protected during even the toughest immune challenges.


  1. National Research Council (US) Committee on Diet and Health. Diet and Health: Implications for Reducing Chronic Disease Risk. Washington (DC): National Academies Press (US); 1989. 14, Trace Elements. Available from:
  2. MP Rayman. Selenium and human health. Lancet. 2012;379(9822):1256-1268.
  3. SM Wood, C Beckham, A Yosioka, H Darban, RR Watson. beta-Carotene and selenium supplementation enhances immune response in aged humans. Integr Med. 2000;2(2):85-92.
  4. BA Carlson, MH Yoo, RK Shrimali, et al. Role of selenium-containing proteins in T-cell and macrophage function. Proc Nutr Soc. 2010;69(3):300-310.
  5. Z Huang, AH Rose, PR The role of selenium in inflammation and immunity: from molecular mechanisms to therapeutic opportunities.Antioxid Redox Signal. 2012;16(7):705-743.
  6. AP Shreenath, MA Ameer, J Dooley. Selenium Deficiency. (Updated 2021 Jul 23). In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: