Cod liver oil for fertility

On this page

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

1. What is cod liver oil?

Cod liver oil is the oil extracted from the liver of cod fish. Unlike regular fish oil (which is extracted from the body of oily fish), cod liver oil contains naturally occurring vitamins A and D in addition to the omega-3 fatty acids EPA and DHA. It has been used as a traditional preconception and pregnancy tonic for centuries, especially in Northern Europe where sunlight-derived vitamin D is scarce.

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

Cod liver oil supports fertility through:

1. EPA and DHA omega-3. Reduces inflammation, improves blood flow to the uterus and ovaries and supports embryo implantation. DHA is critical for foetal brain and eye development.
2. Vitamin A (retinol). Essential for ovarian and testicular function, embryo development and a healthy uterine lining.
3. Vitamin D. Supports oestrogen and progesterone production, sperm quality and successful implantation.
4. Anti-inflammatory action. The combination of EPA, DHA and vitamin D helps regulate inflammatory cytokines.

3. Fertility benefits

Cod liver oil is particularly useful for:

1. Couples preparing for natural or assisted conception
2. People with low vitamin D status (winter months, indoor lifestyles)
3. Women with low oestradiol or thin endometrium
4. Men with poor sperm parameters
5. Women with PCOS or chronic inflammation

4. Recommended daily dose

I recommend a daily dose of 1 teaspoon (5 ml) of high-quality cod liver oil, which typically provides around 800–1,000 mg combined EPA + DHA, 800 IU vitamin A and 400–1,000 IU vitamin D. Avoid high-dose vitamin A (over 3,000 µg RAE / 10,000 IU per day) preconception and during pregnancy — always check the label.

5. Sources

Cod liver oil is sold as:

1. Liquid (most cost-effective)
2. Capsules (more convenient)
3. Flavoured liquid (lemon, orange, mint)

Choose a fermented or molecularly distilled product from cold-water sources, batch-tested for heavy metals (mercury, lead) and PCBs.

6. Cautions and contraindications

1. Avoid high doses of vitamin A in pregnancy — preformed vitamin A above 3,000 µg RAE per day is teratogenic. Check the cod liver oil label before continuing into pregnancy.
2. Cod liver oil has mild blood-thinning effects — do not combine with anticoagulant medication without medical supervision.
3. Stop cod liver oil at least two weeks before any planned surgery.
4. Choose a brand that tests for mercury and PCB contamination.
5. 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
• DHA (omega-3)
• Vitamin A
• Vitamin D
• Vitamin E