Cod Liver Oil vs Fish Oil: Which Is Better For Your Health?

Cod liver oil vs fish oil brings the comparison between the two types of oil that is from the codfish liver and fish oil or any other types of fishes. Cod liver is just a type of fish oil. Both types of fish oil have been used as supplements to provide vitamins and minerals. They can be found easily as bottles sold online or in physical pharmacy stores.

cod vs sardines

Cod liver oil vs fish oil brings the comparison between the two types of oil that is from the codfish liver and fish oil or any other types of fishes. Cod liver is just a type of fish oil. Both types of fish oil have been used as supplements to provide vitamins and minerals. They can be found easily as bottles sold online or in physical pharmacy stores.

What Is COD Liver Oil?

Cod liver oil came from the codfish liver came from the codfish (Gadidae). Its liver contains Omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) that are beneficial to human health. It’s available in soft-gel capsules and sold in plastic or glass bottles and also in packaging. The cod liver oil has a long history back to the 19th century where it was used as a medicine. The early fish oil was foul-tasting as there’s no method to purify it until the invention of the Moller process invented by Peter Moller in 1850. The method involves grounding the liver into a slurry and then skimming it to get the oil.


Codfish liver oil contains DHA and EPA plus vitamins A & D. Cod liver benefits include: 

  • Prevents inflammation
  • Lowers blood pressure
  • Increase HDL or good cholesterol –  Cod liver oil is high in omega 3 fatty acids that can increase good HDL cholesterol and thus lower the risks of heart disease (1, 2)
  • Support bone density
  • Lower blood triglycerides
  • Reduce arthritis pain
  • Prevent illness in the upper respiratory system
  • Promote eyesight and healthy brain function of the fetus.
  • Lowers risk of type 1 diabetes when used during pregnancy and by newborn babies.
  • Prevents plaque from building up in the arteries – Studies on animals have found that cod liver oil may decrease of risks of plaque formation in arteries. Plaques can block arteries and lead to stroke and heart attack (3, 4)
  • Reduce risks of heart disease – A study showed that regular consumption of fish can lead to lower risks of heart disease.
  • Improve anxiety and depression symptoms – Studies have shown that omega 3 fatty acids found in cod liver oil can reduce inflammation that is linked to depression and anxiety. (5, 6)

Health Concerns and Side Effects

Cod liver oil may:

  • Cause belching, nausea, heartburn and bad breath due to the fish nature of oil. Some people report that they have fishy after taste after ingesting the cod liver oil.
  • Cause high levels of vitamins A and D that lead to toxicity.
  • Interfere with the treatment of some medical conditions.
  • Cause an increase in LDL or bad cholesterol


There are no standards for cod liver oil dosage as the dosage depends upon your health, age, gender, and age. You can seek a health care professional advice before taking cod liver oil.

What Is Fish Oil?

Fish oil came from the tissues or meat of oil fishes such as the following:

Atlantic pacific Flounder Mahi-mahi Swordfish
Barramundi Giant tiger prawn Pollock Sydney rock oyster
Blue eye cod Green shell mussels Salmon Tile fish
Blue grenaider Grouper Sardines Cod
Canned tuna Herring Shark Tuna
Catfish Mackerel Silver Gemfish Snapper



Studies have shown that fish oil from food sources and supplements is effective in reducing levels of triglycerides (1). The Federal Drug Administration of the USA approved a fish oil supplement named Lovaza.

Likely effective

  • Heart disease: Eating oily fish and taking fish oil supplements may or might be effective in reducing the risks of heart disease although it’s less clear if fish oil supplements are effective for people who have already taken fish diet.

Possibly effective

  • Re-blockage of blood vessels: Prevent the recurring blockage of blood vessels after the angioplasty surgery which a procedure used to open the closed blood vessel.
  • Bipolar disorder: May improve the symptoms of bipolar disorder but the mania.
  • Heart transplant: Ingesting fish oil may seem to keep kidney function and decrease the long-term increase in blood pressure after a heart transplant.
  • LgA nephropathy: This type of kidney disease is characterized by weight loss, nausea, vomiting, darkened skin, and muscle cramps.
  • Reynaud’s syndrome: Some evidence shows that people who have this syndrome have improved cold tolerance.
  • Kidney damage caused by cyclosporine: This drug is used to prevent an immune system from rejecting the organs.
  • Dry eye
  • Reclosing of artery bypass grafts
  • Developmental coordination disorder or DCD 
  • Menstrual pain
  • Heart transplant
  • Endometrial cancer
  • Dyspraxia or movement disorder in children
  • High blood pressure
  • Psoriasis
  • Stroke
  • Rheumatoid arthritis

Likely ineffective

  • Type 2 and type 1 diabetes 

Possibly ineffective for 

AIDS &HIV Colorectal cancer Ulcerative colitis or IBS
Autism Epilepsy Headache or migraine
Bedsores Hay fever Pregnancy complications
Behcet’s syndrome Pneumonia Premature birth
Blood infection Schizophrenia Renal disease (Advance)
Cancer Phenylketonuria Salicylate intolerance
Cataract Mastalgia or breast pain Helicobacter pylori infection
Cerebrovascular disease Mental function Sepsis or blood infection
Cirrhosis or liver scarring Weight loss Systemic lupus erythematosus
Claudication Muscle strength gain Rapid heart rhythms
Osteoarthritis Pancreatic swelling Clozapine induced abnormal cholesterol levels

No clear evidence for its efficacy against

Asthma Glaucoma Loss of vision due to aging
Hayfever Dyslexia Itchy skin
Autism Chrone’s disease  Eczema
Cataracts Sickle cell disease Chronic fatigue syndrome
Depression Alzheimer’s disease  

Health concerns

Too much fish oil may or might lead to:

  • Bleeding (1) (2) (3)
  • High blood sugar –  High doses of omega 3 can stimulate glucose production which in turn can increase the levels of blood sugar (1)
  • Low blood pressure (1, 2)
  • Diarrhea (1, 2, 3)
  • Acid reflux (1,2)
  • Stroke (1, 2)

Cod Liver Oil vs Fish Oil: Which Is Better?

Both oils have health benefits but cod liver oil has vitamins A and D. There’s no absolute best supplement as it may depend on your needs. If you need the extra benefits of vitamins A and D, cod liver oil is the best. Both oils constitute different benefits and risks as they have been sourced from different fishes and possible synthetic ingredients. 

The Bottom Line

The benefits of fish and cod liver oils can or might improve your health as science has proven the benefits of omega 3 and 6 fatty acids. Take the supplements in moderation and seek professional advice. Also, it can be helpful to avoid self-medication or mixing supplements. Combine a healthy diet with oil supplements for the best results.

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