Best Selenium Supplements (2026) — Ranked by Cost per Effective Dose
Top pick for Selenium: NOW Supplements Selenium 200mcg — 200mcg per 1 capsule, $0.04/day. Our best-value pick.
All Selenium Supplements Compared
All 2 products sorted by cost per clinically-effective daily dose (lowest first). Dose, certification, and pricing verified against NIH DSLD and manufacturer data.
| Product | Brand | Dose / Serving | Cost / Day | Certification | Pick | Buy |
|---|---|---|---|---|---|---|
| NOW Supplements Selenium 200mcg | NOW Foods | 200mcg / 1 capsule | $0.04 | None | Best Value | Buy |
| Life Extension Super Selenium Complex | Life Extension | 200mcg / 1 capsule | $0.11 | None | Buy |
Our Picks
Best Value: NOW Supplements Selenium 200mcg
200mcg per 1 capsule. $0.04/day. 180 servings per container at $7.49.
How We Rank Selenium Supplements
Every product is evaluated on three criteria:
- Cost per clinically-effective daily dose. Not cost per pill or cost per bottle. We calculate what it actually costs per day to take the dose used in clinical trials.
- Third-party certification. USP Verified, NSF Certified for Sport, and ConsumerLab Approved indicate independent testing for purity, potency, and contaminants.
- Bioavailable form. We prioritize products using the specific chemical form shown to be most effective in published research.
Rankings are not influenced by affiliate commissions. We earn the same commission regardless of which product you choose. Read our full methodology.
Personalize Your Selenium Choice
Not sure which selenium supplement is right for you? Use our free tools:
- DNA Supplement Analyzer — upload 23andMe or AncestryDNA data to check for genetic variants affecting selenium metabolism. Runs entirely in your browser.
- Lab Results Interpreter — enter your blood test values to get personalized dosing recommendations.
- Supplement Stack Builder — build a complete protocol based on your age, sex, medications, and goals.
- Supplement Audit — already taking selenium? Check if you have the right form and dose.