Published on June 16, 2021

Cod Liver Oil vs Fish Oil: Which Is Better?

Cod Liver Oil vs Fish Oil: Which Is Better?

Omega-3 fatty acids have so many benefits, such as a reduced risk of cardiovascular disease, type 1 diabetes, certain types of cancer, glaucoma, and stroke. This nutrient is essential for the body’s function, but our bodies are unable to produce them on their own. Therefore, it’s important that we get enough Omega-3 fatty acids from outside sources.

If you’re looking for a way to get your Omega-3 fatty acids in, there are so many ways to do so. If introducing Omega-3s into your diet by eating two to three servings of fish per week doesn’t seem feasible, supplements such as cod liver oil and fish oil are here to help.

Many people use these supplements to boost their health and prevent chronic diseases. In fact, research from the National Institutes of Health showed that, in 2012, 7.8% of adults in the United States and 1.1% of children had taken a fish oil supplement in the previous 30 days.[1]

In this article, I’ll answer the commonly asked question: cod liver oil vs fish oil: which is better? We’ll look at the overall health benefits you can expect from taking Omega-3 supplements and break down the differences between cod liver oil and fish oil.

Facts About Omega-3 Supplements

There are three types of Omega-3 fatty acids: Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA), and Alpha-linolenic acid (ALA). EPA and DHA come mainly from fish while ALA comes mainly from plant sources such as flaxseed and walnuts.[2] Omega-3 supplements such as Cod Liver Oil and Fish Oil provide the EPA and DHA our bodies need.

Omega-3 fatty acids are very important for our heart health. They can reduce the risk of cardiovascular disease and blood clots.[3] They can also help to reduce high blood pressure, which is common among adults in the United States.[4]


Omega-3 supplements can also help to reduce high cholesterol and plaque formation in your arteries.[5][6] They can also help to reduce the risk of sudden cardiac death, which occurs when the heart is either pumping irregularly or ineffectively, making it unable to pump blood as intended to the rest of your vital organs.[7]

One important thing to note is that while getting your Omega-3 fatty acids from dietary sources such as fatty fish provides these benefits, studies have shown that taking Omega-3s in the form of supplements does not reduce the risk of heart disease.[8]

Omega-3 fatty acids have non-cardiac benefits as well. Studies show that they can reduce your risk of glaucoma, certain cancers, and certain mental health disorders.[9][10][11]

Some studies also show that including Omega-3 fatty acids in your lifestyle may lead to improved weight loss when combined with a healthful diet.[12]

With all of these possible benefits, it’s understandable why you would want to increase your Omega-3 intakes. If eating fatty fish, such as tuna or salmon, or plant sources of Omega-3s, such as nuts and seeds, consistently doesn’t seem realistic for your lifestyle, you’d likely be interested in taking an Omega-3 supplement. But which supplement is right for you? Let’s explore the benefits of each.

Are These Supplements Safe?

According to the National Institutes of Health, side effects experienced by users of Omega-3 supplements, if any, are usually mild. These side effects may include unpleasant taste, bad breath, headache, and gastrointestinal symptoms. This could include symptoms such as nausea, diarrhea, or heartburn.[13]


Another thing to note with Omega-3 supplements is that they may interfere with medicines that many Americans take to prevent blood clotting. If you’re on one of these medications or if you have a seafood allergy, it’s important to speak with your doctor before deciding to start taking Omega-3 supplements.

While many consumers may be worried about the mercury content of fish oils, a literature review conducted showed that fish oil capsules do not contain mercury. They noted that when the oil is extracted from the fish, the mercury and other heavy metals that may be present actually stay behind.[14]

How Much Should I Take?

The tricky thing about these supplements is that there is no standard recommended dosage for EPA or DHA. It’s recommended that you read the supplement label and only take the recommended dosage. Especially if you choose to take Cod Liver Oil, it’s important to follow the recommended dosage on the supplement’s label as too much Vitamin A can be toxic.

Regardless of which supplement you’re taking, you can also speak with your primary care doctor to determine what dosage is right for you. If you want to research a particular brand of Omega-3 supplement, you can use the Dietary Supplement Label Database from the National Institutes of Health.[15]

Cod Liver Oil vs Fish Oil Benefits

Here are the differences in the benefits between consuming cod liver oil vs fish oil.

Cod Liver Oil Benefits

Cod Liver Oil was often used at the turn of the 20th century to treat rickets, a bone disease caused by Vitamin D deficiency. This is because Cod Liver Oil contains Vitamin D.[16] Cod Liver Oils tested tended to provide about 400 IU of Vitamin D. The recommended daily intake of Vitamin D for adults is 600 IU, so these supplements provide the majority of what you need.[17]


Getting enough Vitamin D through diet or supplements is especially important for individuals who don’t get a lot of sunlight during the day or don’t already get enough Vitamin D from their diet alone. Additionally, Cod Liver Oil contains Vitamin A, which is important for eye health and immune function.

One important thing to note is that Vitamin A can be toxic in high amounts, so when taking Cod Liver Oil, it’s important to stick to the recommended dosage. Cod Liver Oil also has other possible benefits. It’s long been a popular folk remedy for inducing labor and managing constipation.[18]

Fish Oil Benefits

As opposed to Cod Liver Oil, which is a specific type of fish oil, the commonly called “Fish Oil” supplement is a bit different. Fish Oil supplements typically contain oil that has been extracted from fatty fish, such as herring, tuna, or anchovies.[19]

While Fish Oil also contains Omega-3s and, therefore, has similar benefits to Cod Liver Oil supplements, it has one primary benefit: the fish used in these supplements are fattier than Cod. Therefore, Fish Oil supplements have a higher Omega-3 content.[20] This may mean that taking Fish Oil supplements, as opposed to Cod Liver Oil supplements, may end up giving you a bigger bang for your buck.

Cod Liver Oil vs Fish Oil: Which Is Better?

Both Cod Liver Oil and Fish Oil supplements provide the benefits of Omega-3 fatty acids without having to increase your weekly intake of fatty fishes. They both may provide a reduced risk of glaucoma, improved heart health, and reduced risk of mental health disorders and certain types of cancers.

If you’re looking for a supplement that gets the most bang for your buck, Fish Oil supplements may be right for you. They contain a higher level of Omega-3 supplements than Cod Liver Oil supplements, which may end up being more cost-effective for some consumers.


However, if you have a diet low in Vitamin D or Vitamin A or don’t get enough sunlight during the day, it may be helpful to take an Omega-3 supplement that also contains these vitamins. In that case, Cod Liver Oil may be right for you. One of the drawbacks of this supplement, however, is that it does contain lower levels of Omega-3 than Fish Oil supplements do.

As noted, if you are on blood thinners or have a seafood allergy, it’s important to speak with your doctor before starting any of these supplements.

Whichever supplement you choose, know that these supplements have overall very mild possible side effects and can be a great addition to a healthful diet to promote overall wellness.

Featured photo credit: Caroline Attwood via cod liver oil vs fish oil


[1] NIH: Omega-3 Supplements: In-Depth
[2] Harvard School of Public Health: Omega-3 Fatty Acids: An Essential Contribution
[3] Cleveland Clinic: Omega-3 Fatty Acids
[4] Moderate consumption of fatty fish reduces diastolic blood pressure in overweight and obese European young adults during energy restriction
[5] ResearchGate: Omega-3 fatty acids in health and disease and growth and development
[6] Effect of omega-3 fatty acids supplementation on endothelial function: a meta-analysis of randomized controlled trials
[7] Mayo Clinic: Ventricular fibrillation
[8] NCCIH: Omega-3 Supplements: In-Depth
[9] TVST: Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults
[10] Dietary fatty acids and colorectal cancer: a case-control study
[11] Long-chain omega-3 fatty acids for indicated prevention of psychotic disorders: a randomized, placebo-controlled trial
[12] Randomized trial of weight-loss-diets for young adults varying in fish and fish oil content
[13] NCCIH: Omega-3 Supplements: In-Depth
[14] Anabolic Labs: Fish oil supplementation: Evidence for health benefits
[15] National Institutes of Health: Dietary Supplement Label Database (DSLD)
[16] Vitamin D, cod-liver oil, sunlight, and rickets: a historical perspective
[17] ConsumerLab: What is the difference between fish oil and cod liver oil? Is one better than the other?
[18] NCBI: What Started Your Labor? Responses From Mothers in the Third Pregnancy, Infection, and Nutrition Study
[19] Healthline: What’s the Difference Between Cod Liver Oil and Fish Oil?
[20] Medical News Today: What are the differences between cod liver oil and fish oil?

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Samantha Klig, RD

Registered Dietitian

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Published on August 27, 2021

Should Men Take Fish Oil? 4 Fish Oil Benefits for Men

Should Men Take Fish Oil? 4 Fish Oil Benefits for Men

Fish oil is a well-known healthy food that fits in almost any diet. Most people who want to improve their diet usually try to include fish oil in their daily consumption. But some people may ask: what are the fish oil benefits for men? Is it really good for men’s health? Or is there something fishy about fish oil?

In this article, I will take a comprehensive look at why fish oil is recommended for everyone, especially men. Let’s start with the sources of fish oil and how it could be good for your health.

Fish Oil Sources and Why It Could Be a Good Catch

Fish oil is primarily found and extracted from oily fish varieties, such as salmon, tuna, mackerel, sardine, herring, and trout.[1] It contains two highly beneficial types of omega-3 fatty acids for many health conditions:[2]

  • Docosahexaenoic acid (DHA)
  • Eicosapentaenoic acid (EPA)

But here’s the catch: your human body cannot make omega-3 polyunsaturated fatty acids. You are dependent on food sources to supplement these vital nutrients.[3] But this is not a big deal since you could consume foods that are rich in omega-3 fatty acids, such as oily fish, or consume fish oil in the form of supplements.

As a side note, you can also find another type of omega-3 fatty acid called alpha-linolenic acid (ALA) in some plant sources, such as walnuts, flax seeds, pumpkin seeds, and chia seeds. You cannot find alpha-linolenic acid in fish oil, and interestingly, your body converts ALA into DHA and EPA, but in very small amounts.[4] So, if you want your Omega-3 in balance, you will have to consume DHA, EPA, and ALA via food sources or supplements or a combination of both.

Can Fish Oil Improve Your Health?

The American Heart Association (AHA) recommends consuming oily or fatty cold-water fish twice a week.[5] Fish is one of the best ways to get your omega-3 fatty acids intake and reap its numerous health benefits. It is an excellent source of protein and, in comparison to other fatty meat products, it has low saturated fat.


However, if you’re a vegetarian or do not consume fish, you can consult your doctor for dietary alternatives to fish and fish oil.

Let’s look at some of the fish oil benefits for men, though some of these benefits also apply to everyone.[6]

1. Fish Oil Can Boost Male Fertility

Various research studies have suggested that Omega-3 improves semen quality, volume, erectile function and even prevents prostate cancer.[7]

Recently, the first observational study on the association between fish oil supplementation intake and improved testicular function conducted also showed these supplements to be beneficial to men’s health.[8] The study was conducted on 1,700 young, healthy Danish men who averaged around nineteen years of age. Those who took fish oil supplements reported higher semen volume and improved sperm quality. Those who took other supplements, such as multivitamins did not show the same effects, pointing to possible links between fish oil supplements and better sperm counts.

The study’s lead researcher Tina Kold Jensen, a professor of environmental medicine at the University of Southern Denmark who has been active in this research field for over 25 years, said that these male reproductive factors should lead to improved male fertility in men taking fish oil. Jansen was also optimistic that her research findings would have the same effect on older men who take fish oil supplements.

She concluded that she recommends fish oil supplements for those who want to improve their male fertility. However, she adds that your best options are to increase your fish intake like codfish and follow your doctor’s dietary advice.


Other studies have also found positive associations between fish oil supplements and sperm quality.[9]

While these results have certainly been encouraging, the findings from these observational studies need to be corroborated by more rigorous randomized clinical experiments. Therefore, I encourage patients to discuss their individual cases with their doctors to ensure safety and maximize benefits from fish oil supplements.

2. Fish Oil Helps Maintain a Healthy Heart

Heart disease is the leading cause of death among men, according to the Centers for Disease Control and Prevention (CDC).[10] Overall, it accounts for one in four deaths in America every year.

Fish oil is a heart-friendly nutrient as it is a good source of omega-3 fatty acids. It protects your heart by reducing many of the risk factors for heart disease. Some benefits of fish oil include:[11][12][13]

  • Reduction of triglyceride levels
  • Lowering your blood pressure
  • Reducing your bad cholesterol
  • Preventing blood from clotting
  • Slowing or hindering plaque formation in your arteries
  • Reducing the risk of an abnormal heart rhythm
  • Decreasing your risk of a heart attack and stroke

There is also research that suggests that fish oil supplements reduce adverse situations, such as hospital admissions and death in people with heart failure.[14]

The American Heart Association (AHA) recommends that people without heart disease have at least two servings of fish every week to reduce cardiovascular events. It suggests eating a variety of cold-water, wild fish like tuna, mackerel, salmon, and sardines for their high levels of omega-3 fatty acids. The AHA does not recommend omega-3 supplements for people who don’t have a high risk for cardiovascular disease.[15]


However, if you have heart disease, it’s best to consult your doctor before you decide to take fish oil supplements. Depending on your condition, they might recommend eating more foods rich in omega-3 fatty acids and/or taking an FDA-approved fish oil supplement.

Sometimes, higher doses of omega-3 are given to lower triglycerides. But it should be strictly under the care of a doctor because it can cause complications such as bleeding and affect the immune system.

3. Fish Oil Gives You Clear and Focused Vision

The American Academy of Ophthalmology (AAO) recommends fish oil to optimize your eye health. While there are some conflicting reports, some findings show how fish oil helps treat eye diseases like dry eye and age-related macular degeneration (AMD).[16]

A recent 2019 study supported findings that people who consumed fresh fruits, vegetables, and fish were less likely to develop eye diseases than those who did not.[17] Another study published in Investigative Ophthalmology & Visual Science suggests omega-3 fatty acid DHA for vision protection.[18]

Various studies have found similar findings of fewer dry eye symptoms in those who consumed fish oil. The omega-3 fatty acids in fish oil improved the eye’s oil film produced by meibomian glands situated on the edge of the eyelid.[19] Other studies also found that fish oil reduces pain and swelling, making it an effective treatment for dry eyes.[20]

4. Fish Oil Helps You Become Healthy From the Inside-Out

Fish oil is a versatile nutrient that seems to contribute to several other health benefits. These include:


  • Lowering your depression[21]
  • Boosting your memory[22]
  • Preventing disease-causing inflammation with enhanced B cell activity or white blood cells[23]
  • Aiding in weight loss
  • Giving you healthier skin by clearing your acne and psoriasis[24][25][26]

Why You Need to Stay Cautious About Fish Oil

Fish oil has some possible risks associated with its consumption. Fish oil supplements have common temporary side effects, such as foul taste, smell, belching, heartburn, nosebleeds, rash, nausea, flatulence, and diarrhea.

While fish oil can prevent prostate cancer, excess consumption can increase your risk for high-grade prostate cancer.[27] Fish oil in high doses can cause bleeding, affect your immune system, and reduce your body’s ability to fight off infection.[28]

Certain combinations of medications can cause serious health risks when you take them regularly alongside fish oil. Hence, it would be best if you first discussed with your doctor about taking fish oil along with your prescribed medications.

While fish oil from the source is preferable, some fish meats are prone to mercury contamination and other toxic industrial and environmental chemicals.[29] Mercury contaminated fish meats can cause blindness, brain damage, and mental retardation in children.[30]

What’s the Verdict on Fish Oil?

The fish oil benefits for men and women far outweigh the risks, especially for middle-aged and older people who follow the recommendations by the FDA, AHA, and EPA.

Make fish oil your friend by:


  • Choosing more from food sources than supplements.
  • Following AHA’s recommendation of eating one to two servings of non-fried fish every week.
  • Eating a variety of fish higher in EPA and DHA and lower in methylmercury to minimize potentially adverse effects due to environmental pollutants.
  • Consuming fish along with other vital aspects of a healthy diet, such as fruits, vegetables, dairy products, and whole grains that ensure balanced omega.
  • Getting your doctor’s approval and prescribed fish oil supplement and following their instructions.
  • Following the AHA’s recommendations of consuming no more than 3 grams of fish oil supplement daily, as taking more can cause bleeding.
  • Taking your fish oil supplements into two doses in the morning and night to decrease side effects.
  • Taking fish oil supplements with food to increase absorption and decrease side effects.
  • Freezing and consuming them to decrease side effects.
  • Following the US federal government’s 2020–2025 Dietary Guidelines for Americans recommendations of seafood for pregnant and nursing women. Safe fish options for pregnant and nursing women include sardines, trout, salmon, herring, and anchovies because of higher EPA and DHA and lower mercury.

On a final note, your health is in your hands. Choose wisely, and use fish oil for your health benefit today. But first, consult your doctor for medical advice before making an informed decision on fish oil and taking action.

More About the Benefits of Fish Oil

Featured photo credit: Sam Moqadam via


[1] National Institutes of Health: Omega-3 Fatty Acids
[2] WebMD: The Facts on Omega-3 Fatty Acids
[3] Harvard School of Public Health: Omega-3 Fatty Acids: An Essential Contribution
[4] National Institutes of Health: Omega-3 Fatty Acids
[5] American Heart Association: Fish and Omega-3 Fatty Acids
[6] WebMD: What to Know About Omega-3s and Fish
[7] NCBI: Prostate Cancer Risk And Omega-3 Fatty Acid Intake From Fish Oil
[8] JAMA Network: Associations of Fish Oil Supplement Use With Testicular Function in Young Men
[9] Dietary supplementation with docosahexaenoic acid (DHA) improves seminal antioxidant status and decreases sperm DNA fragmentation
[10] Centers for Disease Control and Prevention: Men and Heart Disease
[11] MayoClinic: Omega-3 in fish: How eating fish helps your heart
[12] Cleveland Clinic: Omega-3 Fatty Acids
[13] Harvard Health Medical School: The complicated relationship between fish oil and heart health
[14] WebMD: Fish Oil
[15] National Institutes of Health: Omega-3 Fatty Acids
[16] American Academy of Ophthalmology: The Benefits of Fish Oil for Dry Eye
[17] NCBI: Nutrients for Prevention of Macular Degeneration and Eye-Related Diseases
[18] Harvard Health Publishing: Omega-3 for your eyes
[19] Mayo Clinic: Mayo Clinic Q and A: Fish oil supplements and dry eyes
[20] WebMD: Fish Oil
[21] Translational Psychiatry: Efficacy of omega-3 PUFAs in depression: A meta-analysis
[22] WebMD: Fish Oil Supplements Boost Memory
[23] Science Daily: Nothing fishy about it: Fish oil can boost the immune system
[24] NCBI: Cosmetic and Therapeutic Applications of Fish Oil’s Fatty Acids on the Skin
[25] Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomized, double-blind, controlled trial
[26] Oxford Academic: Efficacy of fish oil and its components in the management of psoriasis: a systematic review of 18 randomized controlled trials
[27] NCBI: Prostate Cancer Risk And Omega-3 Fatty Acid Intake From Fish Oil
[28] Mayo Clinic: Fish Oil
[29] American Heart Association: Fish and Omega-3 Fatty Acids
[30] World Health Organization: Mercury and health

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