Top 6 Best Selenium Supplements for Thyroid, Immunity & Antioxidant Support (2025)

Selenium is a trace mineral that plays a vital role in thyroid function, immune health, and protection against oxidative stress. While it’s found in foods like Brazil nuts, seafood, and whole grains, many Americans may still fall short of the recommended daily intake due to soil depletion and dietary restrictions. That’s where selenium supplements come in.

Whether you’re looking to support your metabolism, reduce inflammation, or promote reproductive health, the right selenium supplement can make a difference. In this guide, we’ll break down the key benefits, how to choose the right form, and what to look for in a high-quality supplement.

Our Top Picks for Selenium Supplements

1. Best Overall Selenium Supplement: Nutricost Selenium 200mcg (240 Capsules)

• Why? Offers an excellent combination of high dose (200mcg), large supply (240 capsules), and affordability at only $0.06 per count. Made with L-Selenomethionine for superior absorption, it’s non-GMO, gluten-free, and produced in a GMP-certified facility.
• Key Benefits: Supports immune health, thyroid function, and antioxidant protection.
• Best for: Individuals seeking a reliable, high-potency selenium supplement for long-term daily use.

2. Best Liquid Selenium Drops: Go Nutrients Selenium Liquid Drops (1 oz)

• Why? Highly bioavailable liquid form ideal for those who prefer drops over pills. Delivers 200mcg of selenium per serving from selenomethionine with zero fillers, artificial ingredients, or preservatives.
• Key Benefits: Enhances thyroid function, immunity, and energy levels.
• Best for: Users looking for convenient, fast-absorbing selenium in drop form.

3. Best Organic Whole-Food Selenium: Global Healing Selenium 200mcg (2 fl oz)

• Why? Made from certified organic mustard seed extract, providing a whole-food form of selenium with excellent absorption. Non-GMO, gluten-free, and manufactured in a cGMP-certified U.S. facility.
• Key Benefits: Antioxidant protection, thyroid support, and cellular health.
• Best for: Health-conscious users who prioritize organic, plant-based sources.

4. Best Sublingual Selenium Liquid: Triquetra Health Selenium 200mcg (2 oz)

• Why? Delivers selenium as selenomethionine in a sublingual liquid format for enhanced absorption and flexible dosing. Each droplet contains 50 mcg, allowing easy customization.
• Key Benefits: Supports thyroid, brain, heart, and immune function while reducing oxidative stress.
• Best for: Users wanting a sublingual delivery method and adjustable dosages.

5. Best Daily Support for Thyroid & Prostate: PurePremium Selenium 200mcg (100 Capsules)

• Why? Formulated for daily use with bioavailable L-Selenomethionine, supporting thyroid, immune, and prostate health. Made in the USA with a natural herbal extract formula.
• Key Benefits: Helps regulate hormones, boost immunity, and maintain prostate function.
• Best for: Men and women seeking everyday wellness with a U.S.-made selenium formula.

6. Best Budget Option: Force Factor Selenium 200mcg (120 Capsules)

• Why? At just $0.03 per capsule, this is the most affordable option without compromising on quality. Offers 200mcg per serving, is vegan-friendly, and made in GMP-certified U.S. facilities.
• Key Benefits: Promotes immune defense, cellular health, and antioxidant support.
• Best for: Budget-conscious buyers looking for a cost-effective immune support supplement.

Rank	Product	Form	Price per Count	Highlight	Key Benefits	Best For
1️⃣	Nutricost Selenium 200mcg (240ct)	Capsule	$0.06	Best Overall Selenium Supplement	Thyroid support, immunity, antioxidant protection	Users needing long-term high-quality selenium
2️⃣	Go Nutrients Selenium Liquid Drops (1 fl oz)	Liquid	$0.18	Best Liquid Selenium Drops	Thyroid health, energy, antioxidant support	Those preferring liquid form for easy dosing
3️⃣	Global Healing Selenium Drops (2 fl oz)	Liquid	$0.30	Best Organic Whole-Food Selenium	Organic antioxidant, thyroid & heart health	Health-focused users prioritizing organic sources
4️⃣	Triquetra Health Selenium Liquid (2 oz)	Liquid (Sublingual)	$0.07	Best Sublingual Selenium Liquid	High absorption, antioxidant, immune support	Users needing fast-acting and flexible dosing
5️⃣	PurePremium Selenium 200mcg (100ct)	Capsule	$0.13	Best Daily Support for Thyroid & Prostate	Hormone balance, prostate health, immune support	Men and women seeking daily selenium support
6️⃣	Force Factor Selenium 200mcg (120ct)	Capsule	$0.03	Best Budget Option	Immune support, antioxidant defense, cellular health	Budget-conscious buyers needing immune support

1. Best Overall Selenium Supplement: Nutricost Selenium 200mcg (240 Capsules)

Price: $13.95

Nutricost Selenium offers a simple yet highly effective solution for daily selenium supplementation. With 200 mcg of L-selenomethionine per capsule and 240 capsules per bottle, it provides 8 months of consistent support for thyroid, immune, and antioxidant health. The product is non-GMO, gluten-free, soy-free, vegetarian-friendly, and third-party tested for quality—making it a solid choice for those seeking clean and affordable nutrition.

Key Benefits

• Supports thyroid hormone production and metabolism
• Strengthens the immune system
• Acts as a powerful antioxidant
• Promotes male reproductive health and prostate support
• May help stabilize blood sugar and support heart rhythm

Key Ingredients

• Selenium (as L-selenomethionine) – 200 mcg per capsule
• Other ingredients: Rice flour, hypromellose (vegetarian capsule), dicalcium phosphate

Pros

• High potency and bioavailability (L-selenomethionine form)
• Exceptional value at only $0.06 per capsule
• Long-lasting supply (240 capsules)
• Manufactured in a GMP-compliant, FDA-registered facility
• Suitable for vegetarians

Cons

• Some users reported a strong odor
• A few users experienced side effects like cramps or mild discomfort (may be related to overdose or individual sensitivity)

Customer Feedback:

• Value for Money:
  Widely praised for its affordability and quantity. Many users say it’s the best deal for a high-potency selenium supplement. “Great value… will continue to purchase.”
  “The price is right and it works.”
• Effectiveness:
  Users noted improved thyroid function, immune health, and even prostate support. “Strengthened my immune system.”
  “Great for the thyroid… highly recommend.”
• Ease of Use:
  Capsules are small, convenient, and easy to swallow. “Easy to swallow… nicely packaged.”
  “Convenient and no strong taste.”
• Taste & Smell:
  Most users say it has no taste. However, a few mentioned a mild or unpleasant odor. “Tastes good… but oh so stinky!”
  “No flavor… great value.”
• Side Effects:
  A small number of users experienced mild joint pain, stomach issues, or cramping. These may result from exceeding selenium intake. “I had leg cramps in my sleep… had to stop.”
  “Developed stomach pain after a few days.”

Best Suited For

• Budget-conscious users needing long-term selenium support
• Individuals with thyroid or immune concerns
• Men looking to support prostate and reproductive health

Usage Recommendations

• Take 1 capsule daily with food, ideally earlier in the day
• Do not exceed the recommended dose, especially if consuming selenium from other sources

Summary: Nutricost Selenium 200 mcg stands out as one of the most affordable and effective options for long-term use. With high bioavailability, clean ingredients, and over 200 positive reviews on quality and value, it’s an excellent pick for anyone looking for reliable selenium support on a budget.

2. Best Liquid Selenium Drops: Go Nutrients Selenium Liquid Drops (1 oz)

Price: $19.97

Go Nutrients Selenium provides a liquid alternative to traditional capsules, delivering 200 mcg of selenium per serving from L-selenomethionine in a highly absorbable tincture format. With 100 servings per 1 oz bottle and no added fillers or preservatives, it’s an ideal choice for users who have trouble swallowing pills or prefer fast absorption.

Key Benefits

• Promotes healthy thyroid function and metabolism
• Enhances energy, focus, and immune strength
• May improve skin clarity and reduce acne
• Helps support antioxidant defense and overall wellness
• Offers fast absorption in a liquid format

Key Ingredients

• Selenium (as L-selenomethionine) – 200 mcg per 6-drop serving
• Other ingredients: USP-grade vegetable glycerin, purified water

Pros

• High bioavailability liquid form
• Easy to use and mix with beverages
• No artificial sweeteners, gluten, or preservatives
• Manufactured in FDA-registered, GMP-certified facility
• Clean formula with no binders or fillers

Cons

• Taste may not appeal to everyone
• Slightly more expensive per serving compared to capsule forms
• Some reviews noted packaging could be improved for travel

Customer Feedback:

• Effectiveness:
  Strongly praised for boosting thyroid health, mental clarity, and immune balance. Users saw lab result improvements and more energy. “The results are excellent.”
  “Gave me energy… perfect for my health.”
• Ease of Use:
  Highly convenient, with users appreciating how easy it is to add drops to water, coffee, or food. “So easy, just 6 drops a day.”
  “Easy to pack when I travel!”
• Thyroid & Metabolism Support:
  Customers noted improvements in weight management, brain fog, and clarity. “Helps maintain proper weight… able to think straight.”
  “Lost 5 pounds… more focus and energy.”
• Energy & Vitality:
  Many users reported a noticeable boost in energy and metabolism. “Game changer – gave me energy.”
  “Burst of energy every day.”
• Skin & Absorption:
  Praised for helping with skin health and absorbing better than pills. “Helped my acne… will use forever!”
  “Liquid is convenient and absorbs completely.”

Best Suited For

• Individuals seeking fast-acting selenium support
• Those with difficulty swallowing pills
• People managing thyroid conditions or chronic fatigue
• Users focused on clean, additive-free supplementation

Usage Recommendations

• Take 6 drops daily, preferably with meals
• Can be added to water, smoothies, or coffee
• Shake bottle well before use and store in a cool, dry place

Summary: Go Nutrients Selenium Drops are an excellent choice for those who want a fast-absorbing, easy-to-use liquid supplement. Backed by strong customer reviews for thyroid, energy, and skin health benefits, it stands out as the best liquid selenium option—especially for users seeking a clean, non-pill format.

3. Best Organic Whole-Food Selenium: Global Healing Selenium 200mcg (2 fl oz)

Price: $19.95

Global Healing Center’s Selenium Drops offer a plant-based, vegan-friendly selenium supplement sourced from certified organic mustard seed extract. Each serving provides 200 mcg of selenium in a bioavailable liquid form, with a clean, gluten-free, and alcohol-free formula. It’s designed to support thyroid function, immune health, and cellular detox—ideal for health-conscious users who prioritize organic, holistic wellness.

Key Benefits

• Supports thyroid hormone production and metabolism
• Promotes immune function and antioxidant defense
• Aids in detoxification and healthy aging
• May improve hair, skin, and nail strength
• Highly absorbable organic formula

Key Ingredients

• Selenium (from certified organic mustard seed extract) – 200 mcg per 0.5 mL
• Other ingredients: Triple-distilled water, organic vegetable glycerin

Pros

• 100% plant-based selenium from organic mustard seed
• Liquid format for fast absorption
• Free from GMOs, gluten, soy, alcohol, and synthetic additives
• Easy to dose for personalized supplementation
• Made in the USA at an eco-conscious facility

Cons

• Higher price point per serving
• Taste may not be preferred by all users
• Glass dropper bottle may not be travel-friendly

Customer Feedback:

• Effectiveness:
  Users consistently report improved thyroid labs, energy, and focus after use. “My thyroid levels improved within weeks.”
  “Mental clarity and energy are noticeably better.”
• Ingredient Quality:
  Customers love the organic, plant-based sourcing and clean label. “Cleanest selenium supplement I’ve found.”
  “No additives—just what I needed.”
• Ease of Use:
  Most find it convenient to take, especially those avoiding pills. “Perfect alternative to tablets.”
  “A few drops in juice, and I’m good to go.”
• Taste:
  Mixed opinions—some found it mild and easy, others less so. “Tastes fine to me.”
  “Not the best flavor but worth it for the benefits.”
• Packaging:
  A few users mentioned the glass dropper could be fragile or messy. “Great product, wish the dropper was sturdier.”

Best Suited For

• Users who prefer organic, clean-label supplements
• Individuals with thyroid conditions or detox goals
• Those who avoid capsules or have dietary sensitivities
• Health-conscious consumers seeking a premium formula

Usage Recommendations

• Take 0.5 mL (approx. 1 dropper) daily, ideally with a meal
• Can be mixed into water or juice for improved taste
• Shake well before use and refrigerate after opening for freshness

Summary: Global Healing Center Selenium Drops are a premium organic choice for those who value plant-based, fast-absorbing nutrition. With clean ingredients and strong thyroid and detox support, it’s an ideal pick for users looking for the best in purity and performance.

4. Best Sublingual Selenium Liquid: Triquetra Health Selenium 200mcg (2 oz)

Price: $21.97

Triquetra Health’s Selenium supplement is a sublingual liquid formula crafted for rapid absorption and ease of use. Each serving provides 200 mcg of selenium in the highly bioavailable L-selenomethionine form. Packaged in a glass dropper bottle with 300 servings, it’s designed to support antioxidant defense, thyroid health, and immune function—all without yeast, gluten, or synthetic additives.

Key Benefits

• Rapid sublingual absorption for better bioavailability
• Supports thyroid hormone production and metabolism
• Enhances immune system activity
• Protects cells from oxidative stress
• Ideal for people who dislike swallowing pills

Key Ingredients

• Selenium (as L-selenomethionine) – 200 mcg per 0.25 mL serving
• Other ingredients: Purified water, organic vegetable glycerin

Pros

• Liquid sublingual format for fast, efficient absorption
• 300 servings per bottle—excellent long-term value
• Vegan, non-GMO, gluten-free, and yeast-free
• No synthetic preservatives or additives
• Comes in an amber glass bottle for purity and stability

Cons

• Taste may not appeal to all users
• Requires measuring drops carefully for accurate dosing
• Not travel-friendly compared to capsules or tablets

Customer Feedback:

• Value for Money:
  Users highlight the high number of servings and clean formulation as excellent value. “A little goes a long way. 300 doses in a bottle—impressive.”
  “I love that it’s clean and simple with no fillers.”
• Effectiveness:
  Many report noticeable improvement in thyroid health, energy, and reduced hair loss. “Helped me balance my thyroid and stop shedding hair.”
  “I feel more energetic and focused.”
• Ease of Use:
  Mixed feedback—while some find the liquid format convenient, others find the taste or measuring inconvenient. “Easy to take under the tongue—no pills!”
  “Taste is okay, but I wish it came with a flavor option.”
• Absorption & Digestive Tolerance:
  Positive reports on absorption and tolerance, especially for users with digestive issues. “No stomach upset like I had with pills.”
  “Perfect for my sensitive digestion.”

Best Suited For

• Individuals with difficulty swallowing capsules
• Those seeking fast-absorbing, yeast-free selenium
• Users focused on thyroid, immune, or antioxidant support without synthetic fillers

Usage Recommendations

• Take 0.25 mL daily under the tongue, hold for 15–30 seconds before swallowing
• Shake well before use and store in a cool, dry place
• Best taken with or after meals

Summary: Triquetra Health Selenium Liquid offers a clean, fast-absorbing, and yeast-free option perfect for those who prefer liquid supplements. With 300 vegan servings in each bottle, it’s a great value for those prioritizing thyroid and immune support.

5. Best Daily Support for Thyroid & Prostate: PurePremium Selenium 200mcg (100 Capsules)

Price: $14.99

PurePremium Selenium delivers 200 mcg of L-selenomethionine in each easy-to-swallow capsule. This formula is crafted to support immune defense, thyroid hormone regulation, and prostate function. Made in the USA with clean-label ingredients, it offers a 3-month supply at a reasonable price point.

Key Benefits

• Supports thyroid hormone balance and metabolism
• Strengthens immune system function
• Promotes normal prostate and reproductive health
• Provides antioxidant protection against oxidative stress

Key Ingredients

• Selenium (as L-selenomethionine) – 200 mcg per capsule
• Other ingredients: Vegetable capsule, rice flour, magnesium stearate (vegetable source)

Pros

• Uses bioavailable L-selenomethionine for superior absorption
• Clean formula with no artificial additives
• Non-GMO, gluten-free, and made in the USA
• Tailored for daily use by both men and women

Cons

• Slightly higher cost per capsule compared to larger bottles
• No additional nutrients to complement selenium benefits

Customer Feedback

• Effectiveness:
  Users report improvements in thyroid energy, clearer skin, and a general boost in well-being. “Helped normalize my thyroid lab results.”
  “I feel more balanced and energized.”
• Ease of Use:
  The capsules are small, easy to swallow, and well tolerated. “Capsules go down easily and no bad aftertaste.”
  “Perfect size and easy on my stomach.”
• Quality & Clean Label:
  Customers appreciate the natural, no-filler formula and U.S.-based production. “Great quality and no junk ingredients.”
  “Love that it’s made in the USA.”
• Price vs. Supply:
  Generally viewed as affordable for a 3-month supply, though not the cheapest option. “Worth the price for a clean and effective supplement.”

Best Suited For
Men and women looking for a straightforward selenium supplement to support thyroid health, immunity, and prostate function with clean, trustworthy ingredients.

Usage Recommendations
Take 1 capsule daily with food. Best taken in the morning or with a main meal to support absorption and energy production.

Summary: PurePremium Selenium offers targeted daily support for thyroid and immune function with a clean, bioavailable formula. It’s a strong choice for users wanting effective, no-nonsense selenium in capsule form.

6. Best Budget Option: Force Factor Selenium 200mcg (120 Capsules)

Price: $7.49

Force Factor Selenium provides 200 mcg of selenium per capsule, designed to support immune system resilience and overall antioxidant protection. This vegan, non-GMO formula comes from a well-known brand in the immunity and performance supplement space and offers a convenient daily capsule format.

Key Benefits

• Strengthens immune response and cellular defense
• Helps reduce oxidative stress
• Supports thyroid hormone metabolism
• Contributes to cardiovascular and cognitive health

Key Ingredients

• Selenium (as L-selenomethionine) – 200 mcg per capsule
• Vegan-friendly capsules, free of GMOs, gluten, and synthetic fillers

Pros

• High-potency 200 mcg dose in each serving
• Clean label: non-GMO, vegan, gluten-free
• Made in the USA with quality standards
• Convenient once-daily capsule

Cons

• No additional cofactors (like vitamin E or zinc) to enhance synergistic effects
• Basic formula compared to some multi-ingredient competitors

Customer Feedback

• Value for Money: Users find it well-priced for a high-quality selenium supplement, especially with 120 servings per bottle.
• Effectiveness: Customers report feeling more resilient during cold seasons and improved energy and mental focus.
• Ease of Use: Once-a-day capsule is easy to swallow with no aftertaste or digestive issues.
• Side Effects: Rare, but a few sensitive users noted mild upset if taken on an empty stomach.
• Overall Rating: A strong daily selenium option with high trust in Force Factor’s brand quality.

Best Suited For
People looking for a clean, effective selenium product to support long-term immune and thyroid health, especially those on plant-based diets.

Usage Recommendations
Take 1 capsule daily with food, preferably in the morning for better absorption and energy support.

Summary: Force Factor Selenium is a reliable, vegan-friendly supplement offering a potent 200 mcg dose in each capsule. It’s a great option for immune and thyroid support with simple, clean ingredients from a reputable brand.

What Is Selenium and Why Should You Supplement It?

Selenium is an essential micronutrient that your body cannot produce on its own. It functions primarily as a component of antioxidant enzymes (like glutathione peroxidase), helping to neutralize free radicals and prevent cellular damage.

Selenium is also critical for:

• Thyroid hormone production: Selenium is necessary to convert the thyroid hormone T4 into its active form, T3.
• Immune response: It helps regulate inflammation and strengthens your body’s defense against pathogens.
• Reproductive health: Especially in men, selenium supports sperm production and motility.
• Brain and heart health: Its antioxidant properties may protect against cognitive decline and cardiovascular damage.

Most Americans need around 55 mcg per day, but therapeutic doses in supplements range from 100 to 200 mcg.

Key Benefits of Selenium Supplements

1. Supports Thyroid Function
   Selenium is essential for the synthesis and metabolism of thyroid hormones, helping to maintain energy levels and metabolic balance.
2. Boosts Immune Health
   It plays a role in regulating immune cell activity, making it helpful for people with weakened immunity or autoimmune conditions.
3. Fights Oxidative Stress
   As a cofactor for antioxidant enzymes, selenium helps protect cells from inflammation and free radical damage.
4. Promotes Reproductive Health
   It supports fertility, especially in men, by improving sperm quality and motility.
5. Protects Brain & Heart
   Adequate selenium intake may reduce the risk of cognitive decline and support healthy circulation and blood pressure levels.

How to Choose the Best Selenium Supplement

When shopping for a selenium supplement, keep these factors in mind:

• Form of Selenium:
  • L-selenomethionine (yeast-bound or organic): best absorbed and well-tolerated
  • Sodium selenite/selenate: less bioavailable and may cause digestive discomfort in high doses
  • Selenium-enriched yeast: offers natural co-factors and high absorption
• Dosage:
  • Ideal daily supplement dose is typically 100–200 mcg
  • Avoid exceeding 400 mcg/day, which may increase the risk of selenium toxicity
• Delivery Format:
  • Capsules and tablets are common and shelf-stable
  • Liquid forms allow for flexible dosing
  • Softgels may offer better absorption for some individuals
• Additional Features:
  • Non-GMO, gluten-free, yeast-free (if sensitive), and third-party tested
  • Combination formulas with zinc or vitamin E for added immune/skin support

Who Should Consider Taking Selenium Supplements?

Selenium supplements may benefit:

• Individuals with thyroid disorders like Hashimoto’s or hypothyroidism
• People following plant-based or low-selenium diets
• Men seeking to improve fertility and reproductive health
• Those experiencing frequent fatigue or immune challenges
• Adults aiming to support anti-aging, heart, and cognitive health

Safety and Side Effects

Selenium is generally safe when taken in appropriate doses. However, chronic high doses (over 400 mcg/day) can lead to toxicity, with symptoms like:

• Nausea
• Hair loss
• Fatigue
• Irritability
• Garlic-like breath odor

Always check the supplement facts panel and consult your healthcare provider if you’re taking thyroid medications or other mineral supplements.

FAQ (Frequently Asked Questions)

Final Verdict

Selenium is one of the most underrated trace minerals for overall wellness. From thyroid balance to fertility and immune defense, the right supplement can fill nutritional gaps and provide lasting benefits—especially if you’re not consistently getting selenium from food.

Sharing is caring!