Selenium · low result
What does a low Selenium mean?
Short answer
Low selenium reflects intake — soil selenium varies by region, and people eating mainly locally grown food in low-selenium areas, on restricted or long-term tube-fed diets, or with malabsorption run low — plus higher needs in dialysis, HIV and critical illness. Selenium supports thyroid hormone activation and antioxidant enzymes; deficiency is linked to hypothyroidism symptoms, muscle weakness, heart muscle disease (Keshan disease) and impaired immunity. Acute inflammation lowers the measured level transiently.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
What is the normal range for Selenium?
- age 18+: 70.0 – 150 mcg/L
Can reflect malabsorption or low-selenium diets in certain regions.
Full reference table, citations and testing options: Selenium biomarker page.
What are the common causes of low Selenium?
- Low dietary intake (low-selenium soils, restrictive or vegan diets without Brazil nuts, seafood or grains from selenium-rich regions)
- Malabsorption: celiac disease, Crohn's, bariatric surgery, short bowel
- Long-term parenteral or enteral nutrition without selenium
- Kidney disease on dialysis, HIV, critical illness
- Phenylketonuria and other medically restricted diets
- Acute inflammation (transient false low)
What symptoms go with low Selenium?
- Often none
- Fatigue, muscle weakness or pain, hair loss, whitened nail beds
- Symptoms of low thyroid function, frequent infections
- Heart failure symptoms in severe long-standing deficiency
What do clinicians usually check next?
- Repeat when well (CRP alongside)
- TSH and Free T4/Free T3
- Dietary review — a few Brazil nuts a week or seafood usually suffices; supplements are dosed to avoid excess (upper limit 400 mcg/day)
Follow-up tests available at TestWell: TSH (Thyroid Stimulating Hormone) ($26.99), TSH + Free T4 ($27.99), Free T3 (Triiodothyronine) ($30.99), C-Reactive Protein (CRP) ($26.99), Free T4 (Thyroxine) ($23.99), T3 Uptake ($22.99).
How do you recheck Selenium?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Vitamin & Mineral Deficiency Panel | Panel · 9 tests | $189.99 | No | 3–5 business days |
| Men's Hair Health Panel | Panel · 19 tests | $499.99 | No | 4–7 business days |
| Women's Hair Health Panel | Panel · 19 tests | $469.99 | No | 4–7 business days |
| Selenium | Test | $64.99 | No | 3–7 business days |
Common questions
How much selenium do I need?
55 mcg a day for adults. One Brazil nut can supply that or more, which is also why taking Brazil nuts plus a supplement is the usual route to excess (hair loss, brittle nails, garlic breath).
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.