Is selenium good to take every day? Understanding this Essential Trace Mineral

November 3, 2025 •

3 min read

According to the National Institutes of Health, most adults need a certain amount of selenium daily, making it an essential trace mineral for health. Understanding if is selenium good to take every day depends heavily on your existing dietary intake and whether you're at risk of deficiency.

Quick Summary

Taking selenium daily is important for health if intake is appropriate, but most people meet their needs through food. Excessive daily intake, particularly from supplements, can cause toxicity. Optimal intake supports thyroid function, reproduction, and immune health, while high levels risk hair loss, nail brittleness, and neurological issues.

Key Points

Daily Intake is Key, But Often Met: Meeting the recommended daily amount is important, and many people achieve this through their diet.
Moderation is Essential with Supplements: Selenium has a narrow safe intake range, and consistently high intake can lead to toxicity.
Food is a Primary Source: Getting selenium through a balanced diet of foods like Brazil nuts, seafood, meat, and whole grains is a safe way to meet needs.
Supplements for Deficiency Only: Only individuals with a medically confirmed deficiency, such as those with certain GI disorders or undergoing dialysis, should typically consider supplementation.
Watch for Toxicity Signs: Symptoms of selenosis include hair loss, brittle nails, nausea, and a garlic-like breath odor, indicating that intake may be too high.
Consult a Professional: Always speak with a healthcare provider before starting a daily selenium supplement, as they can assess your needs and guide your intake.

Selenium is a trace mineral that is essential for human health, playing a crucial role in many bodily functions. It acts as a powerful antioxidant, helping to protect cells from damage caused by oxidative stress. It also plays a vital role in thyroid hormone metabolism, DNA synthesis, reproduction, and protecting the body from infections. While daily intake is necessary, the question of whether to take a daily supplement depends on your individual circumstances.

The Role of Selenium in Your Body

Selenium's functions are critical for maintaining overall well-being. It is a key component of selenoproteins, which have various health benefits.

Antioxidant Defense: Selenoproteins like glutathione peroxidase act as potent antioxidants, neutralizing free radicals that can cause cellular damage. This protective effect is linked to a reduced risk of chronic diseases such as heart disease and some cancers.
Thyroid Function: The thyroid gland has a high concentration of selenium. This mineral helps regulate thyroid hormone production and protects the gland from oxidative stress.
Immune System Support: A healthy immune system depends on adequate selenium levels to function effectively and fight off infections.
Reproductive Health: Selenium is essential for proper reproductive function in both men and women. For men, it is needed for sperm motility, while in women, it can reduce the risk of pregnancy complications.

Daily Intake and Getting Enough Selenium

The recommended dietary allowance (RDA) for selenium varies based on age and life stage. It is important to be aware that exceeding the tolerable upper intake level (UL) can be dangerous.

Food sources of selenium

Most people can meet their daily selenium requirements through a balanced diet, as the mineral is present in many common foods. The selenium content of plant-based foods can vary depending on the soil where they were grown.

Brazil Nuts: This is a notable natural source of selenium.
Seafood: Tuna, cod, sardines, and shrimp are good sources of selenium.
Meats: Beef, poultry, and organ meats contain this mineral.
Grains and Cereals: Whole grains, fortified bread, and pasta are sources.
Other Foods: Eggs, cottage cheese, mushrooms, and legumes also contribute to selenium intake.

Do you need a selenium supplement?

For most people in countries with selenium-rich soil, like the United States, supplementation may be unnecessary and could lead to excessive intake. However, supplements may be considered for certain individuals who are at a higher risk of deficiency, including:

Individuals with chronic gastrointestinal conditions like Crohn's disease or celiac disease, which can impair nutrient absorption.
People undergoing kidney dialysis.
Those with HIV.

The Risks of Excessive Daily Selenium Intake

While essential, selenium has a narrow therapeutic range. Consistently high intake, especially from supplements, without a confirmed deficiency, can lead to a toxic condition called selenosis.

Side effects of selenium toxicity

Garlic-like odor on the breath
Hair loss and brittle nails
Nausea, vomiting, and diarrhea
Skin rashes
Fatigue and irritability
In severe cases, neurological symptoms, heart failure, and kidney failure

Comparison: Getting selenium from diet vs. supplements


Feature	Dietary Intake (from food)	Supplemental Intake (from pills)
Selenium Level	Variable, dependent on soil quality and food choices.	Fixed amount. Risk of overconsumption exists if intake is not monitored.
Absorption	Generally absorbed effectively by the body.	Can have a high absorption rate, potentially increasing the risk of toxicity at high intakes.
Associated Nutrients	Comes with a host of other vitamins, minerals, and nutrients.	Isolated nutrient; lacks synergistic benefits of whole foods.
Risk of Toxicity	Very low. Unlikely to reach toxic levels from food alone.	Higher risk, especially if daily intake is consistently high.
Best For	Meeting daily needs for most healthy people.	Addressing a medically diagnosed deficiency under a doctor's supervision.

Conclusion

Is selenium good to take every day? Yes, in the appropriate amount, as it is an essential mineral for numerous body functions. However, for most people, the safest and most effective way to ensure adequate daily selenium intake is through a balanced diet rich in selenium-containing foods like seafood, meats, and Brazil nuts. The average dietary intake in many Western countries often meets or exceeds the RDA. For anyone considering a daily selenium supplement, it is crucial to consult with a healthcare provider to assess potential deficiency and determine if supplementation is necessary, ensuring total daily intake remains within safe limits. A cautious approach to supplementation is key to maximizing benefits and avoiding the risks associated with toxicity.

For more information on the health benefits of essential nutrients, visit the NIH Office of Dietary Supplements.(https://ods.od.nih.gov/factsheets/selenium-healthprofessional/)

Frequently Asked Questions

The recommended daily allowance (RDA) for most adults varies by age and life stage, with specific recommendations for pregnant and breastfeeding women.

Excellent food sources include Brazil nuts, seafood like tuna and cod, lean meats, poultry, eggs, and whole grains.

Excessive intake of selenium can lead to selenosis, a toxic condition with symptoms including hair loss, brittle nails, garlic breath, nausea, and, in severe cases, neurological or heart problems.

While it is possible, selenium toxicity from food alone is very rare. The risk is much higher from taking high-dose supplements, particularly if you are already consuming sufficient amounts from your diet.

Supplements are typically recommended only for individuals with a diagnosed selenium deficiency. This can occur in those with chronic gastrointestinal diseases or people undergoing kidney dialysis.

Selenium deficiency is rare in many developed countries but can lead to health issues such as worsening iodine deficiency and certain types of heart disease or arthritis.

Most of the selenium you consume is excreted from the body within 24 hours. However, it can accumulate in certain tissues, which is why chronic, high-dose supplementation can lead to toxicity over time.