Cod Liver Oil vs. Fish Oil: Comparison and Health Benefits

Omega-3 supplements are among the most commonly used supplements in the world, but have you ever wondered how one differs from another? 

Both fish oil and cod liver oil come from fish, and both are known for their omega-3 content. Each brings its own nutritional strengths and limitations to the table.  

But how do you know which one is for you? For that, you must understand the differences and benefits of cod liver oil and fish oil.  

This blog breaks down everything you need to know, from nutrient profiles and science-backed benefits to safety tips and pregnancy guidance, so that you can confidently choose the right supplement for your wellness journey. 

What Is Fish Oil and Cod Liver Oil? 

Fish oil is a supplement made from the tissues of various fatty fish species, including salmon, mackerel, sardines, and anchovies. It is mainly used as a source of two long-chain omega-3 fatty acids:  

Cod liver oil, on the other hand, comes specifically from the liver of atlantic codfish. 

Since the liver is a storehouse of fat-soluble nutrients, this makes the supplement unique. It provides natural fat-soluble vitamins A and D along with its omega-3 content. (1) 

Now that you know what sets fish oil and cod liver oil apart, let’s look at the health benefits each one offers. 

Benefits of Fish Oil  

Fish oil is rich in omega-3 fatty acids, especially EPA and DHA, which play a major role in regulating inflammation, circulation, and cell function. 

Benefits of fish oil are:  

High levels of triglycerides, a type of fat found in the blood, can increase the risk of heart attacks. 

EPA and DHA may reduce triglyceride production in the liver and support the breakdown of fatty acids.(2) 

Clinical data shows that optimal daily intake of EPA and DHA relaxes blood vessels and helps lower blood pressure numbers.(3) 

Atherosclerosis is a condition in which fatty deposits, called plaque, are deposited in the arteries and restrict blood flow. Fish oil reduces inflammation within arterial plaque and makes it more stable. 

Under normal conditions, tiny blood cells called platelets activate and stick together at the site of an injury to form a plug and stop bleeding.  

However, in certain clinical situations, such as atherosclerosis or chronic inflammation, these platelets become hyperactive, increasing the risk of unwanted clot formation within arteries. 

The EPA and DHA in fish oil become part of the platelet structure and change the signals platelets produce. This lowers the amount of thromboxane A2, a substance that makes platelets stick together and causes blood vessels to tighten. 

With less thromboxane A2, platelets do not clump unnecessarily and support smoother blood flow without blocking the body’s ability to form a clot when there’s a real injury. 

Fish oil may activate antioxidant pathways that help protect blood vessels and heart cells from oxidative damage.(2) 

Also Read: 10 Highly Inflammatory Foods to Avoid & 10 Anti-Inflammatory Foods to Include in Your Diet 

DHA, found in both supplements, plays an important role in brain structure and function.  

Research on omega-3s in older adults suggests that higher omega-3 levels are associated with better memory, processing speed, and structural brain measures, and a 2023 review reported that DHA may help slow cognitive decline in some people.(4) 

You will be surprised to know that 60% of the brain’s dry weight is made up of fat. This is where omega-3 fatty acids play an important role. (5) 

It maintains cell structure and supports communication between neurons and reduces inflammation in the brain and increases blood flow to the brain. 

Fish oil improves insulin sensitivity in the body by raising the levels of adiponectin, a hormone that supports insulin sensitivity and metabolic health. 

DHA and other omega-3 help protect the insulin-producing cells of the pancreas from stress and dysfunction and limit excess fat storage in the body.(2) 

EPA and DHA reduce the production of certain pro-inflammatory compounds and may reduce the multiplication of abnormal cancer cells. Alongside, fish oil supports apoptosis, the body’s natural process of removing damaged or abnormal cells.(2) 

DHA forms a part of the retinal membrane; therefore, it helps to maintain retinal structure and normal visual function.(2) 

Some studies suggest omega-3s can improve tear stability and ease dry-eye symptoms, although research is still ongoing.  

In a study by Augood and colleagues on adults (65 years), it was seen that adults who ate oily fish at least once a week had 53% lower chances of developing age-related macular degeneration, a condition that affects the central part of the retina (macula) responsible for sharp, detailed vision.(6) 

Research also suggests that long-chain omega-3 intake (from fish liver oil) during pregnancy can reduce the risk of preterm and early preterm birth. 

Studies suggest that omega-3 fatty acids may support joint comfort by reducing inflammation and easing pain. 

In a meta-analysis of randomized trials, giving omega-3 supplements lowered the need for painkillers (NSAIDs) in rheumatoid arthritis patients and also improved morning stiffness. 

Also Read: Support Your Wellness Naturally: Exploring Tocotrienols' Potential for Inflammation! 

Benefits of Cod Liver Oil 

Cod liver oil provides the same core omega‑3 benefits as fish oil (cardiovascular support, brain function, blood sugar regulation, joint health, and more), as it contains same EPA and DHA. 

The difference between cod liver oil and fish oil, which sets it apart, is that cod liver oil is also a natural source of vitamin A and D, sourced directly from the liver, making cod liver oil a dual-purpose supplement for both heart and overall wellness. 

So, while fish oil is usually the more focused omega‑3 supplement, cod liver oil brings a broader nutrient profile to the table as: 

 Vitamin D in cod liver oil supports calcium absorption, which is important for building and maintaining dense, resilient bones necessary for bone strength.(7) 

Also, vitamin A, present in cod liver oil, supports bone remodeling and the formation of new bone tissue, helping prevent age-related bone loss and fractures. 

Cod liver oil boosts immunity in three simple ways:  

The two nutrients (Vitamin A and DHA) present in cod liver oil supports vision and eye health independently by two different ways: 

Together, they work in complementary ways: vitamin A enables light detection, while DHA maintains the retina’s physical integrity and function. 

Also Read: The 8 Best Foods to Boost Your Immune Health 

NOTE: Since vitamins A and D are fat-soluble, the body stores them in tissues rather than flushing out the excess through urine, as it does with water-soluble vitamins. That’s why cod liver oil needs more careful dose monitoring. 

It might be clear by now that cod liver oil and fish oil may look similar at first glance, but their nutrient profiles tell a different story.

Before you start taking either supplement, it’s important to understand a few safety considerations. 

Are Fish Oil and Cod Liver Oil Safe?  

Yes, both of them are safe for most healthy adults at recommended doses, but cod liver oil carries a risk of vitamin A overdose. In contrast, there is no such risk with fish oil.  

 Be careful if you are taking cod liver oil supplements; always monitor your total vitamin A intake. The National Institutes of Health recommends that total vitamin A intake should not exceed 3,000 mcg from all sources to avoid toxicity. 

High levels of vitamin A can be harmful to a developing baby, so pregnant individuals should avoid fish liver oils unless specifically prescribed by the doctor. 

According to the NIH Office of Dietary Supplements, cod liver oil may prolong clotting time when taken with blood thinners like warfarin. It can also interact with your blood pressure medications or anti-diabetic drugs. 

Always speak to a healthcare professional before adding it to your routine if you take these medications for high blood pressure or diabetes. 

Some people notice a fishy aftertaste or repeat fishy burps after taking cod liver oil or fish oil. 

These supplements can sometimes cause mild stomach discomfort, nausea, or loose stools. 

How much fish oil and cod liver oil supplements should you take daily?

Before you choose, know what to look for, and what to skip.

Conclusion 

Fish oil and cod liver oil aren't competing supplements; they simply serve different purposes. 

If your goal is to get more EPA and DHA without adding extra vitamins, fish oil is usually the better fit. If you'd also like the added nutritional support of vitamins A and D, cod liver oil can be a smart choice, as long as you're mindful of how much vitamin A you're getting from other sources. 

The bottom line? Don't choose based on what's trending. Choose the supplement that fills a gap in your diet and aligns with your health goals. And whatever you pick, make sure it's sourced from a reputable brand that's transparent about purity, potency, and quality testing. 

A well-made supplement can't replace healthy habits, but it can be a valuable addition to them.

FAQs 

Q1. What are the health benefits of taking cod liver oil and fish oil supplements? 

Q2. Are there any differences between fish oil and cod liver oil in liquid form? 

Q3. How to choose high-quality fish oil and cod liver oil supplements? 

Q4. Are there signs that I may be getting too much vitamin A from cod liver oil? 

Possible signs can include nausea, dizziness, headache, or other symptoms of excess vitamin A, which is why total intake should stay within safe limits. 

References