Selenium for fertility

On this page

1. What is selenium?
2. Function and how it works
3. Fertility benefits
4. Recommended daily dose
5. Food sources
6. Cautions and contraindications
7. My Fertility Guide
8. Related pages

1. What is selenium?

Selenium is widely considered the most important trace element in our diet for fertility. Low selenium levels are linked with miscarriage, pre-eclampsia, poor sperm motility and reduced thyroid function. Selenium is incorporated into selenoproteins, which include glutathione peroxidase — one of the body's master antioxidant enzymes — and the deiodinase enzymes that convert T4 to active T3.

Reference ranges and recommended intakes vary from country to country — always interpret guidance against the recommendations of your own healthcare authority.

2. Function and how it works

Selenium supports fertility through several mechanisms:

1. Antioxidant defence. Glutathione peroxidase, a selenoprotein, neutralises hydrogen peroxide and other free radicals that would damage eggs and sperm.
2. Thyroid hormone activation. Selenium is required for converting T4 (the thyroid storage hormone) to T3 (the active form), which directly supports ovulation and a healthy uterine lining.
3. Sperm motility. Selenium is concentrated in the sperm tail and is required for healthy sperm movement.
4. Sperm DNA integrity. Selenium protects sperm DNA from oxidative damage.
5. Miscarriage prevention. Low selenium has been linked with recurrent miscarriage and pre-eclampsia.

3. Fertility benefits

Selenium is one of the most important supplements for both male and female fertility. For men with poor sperm motility, selenium supplementation has been shown to improve sperm function. For women with thyroid-related fertility difficulties, autoimmune thyroid disease or recurrent miscarriage, selenium is part of a comprehensive approach. Each ejaculation depletes selenium, so men benefit from steady daily intake.

4. Recommended daily dose

I recommend a daily dose of 200 mcg of selenium for both men and women trying to conceive. The selenomethionine form is preferable to inorganic selenite. Just 2–3 Brazil nuts a day provide the daily requirement, though selenium content in Brazil nuts varies considerably depending on the soil they grew in.

5. Food sources

Selenium is found in:

1. Brazil nuts (the richest source)
2. Fish (sardines, tuna, salmon)
3. Poultry (chicken, turkey)
4. Meats (beef, lamb)
5. Whole grains
6. Mushrooms
7. Onions and garlic
8. Broccoli and cabbage
9. Eggs

6. Cautions and contraindications

1. Selenium has a relatively narrow therapeutic window. Long-term doses above 400 mcg per day can cause selenium toxicity (selenosis), with symptoms including hair loss, brittle nails and a garlic odour to the breath.
2. Eating too many Brazil nuts (more than 5–6 per day) can result in selenium overdose.
3. Always consult with a fertility specialist or your doctor before starting any new supplement regime.

7. My Fertility Guide

8. Related pages

• Fertility supplements directory
• Iodine — works with selenium for thyroid hormone production
• Zinc
• Vitamin E
• Coenzyme Q10
• Thyroxine (T4) and triiodothyronine (T3)
• Male infertility
• Miscarriage