What are the effects of omega-3 fatty acids found in fish oil?

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Last updated: April 29, 2025View editorial policy

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From the Guidelines

Prescription omega-3 fatty acid products, not nonprescription fish oil supplements, are recommended for the management of elevated triglyceride levels and ASCVD risk reduction due to their verified efficacy, consistent content, and purity, as well as FDA approval for this indication. When considering the use of fish oil for heart health, it's essential to distinguish between prescription omega-3 fatty acid products and nonprescription fish oil supplements. The former has been demonstrated to have cardiovascular outcomes benefits and is recommended for ASCVD risk reduction, particularly in patients with elevated triglyceride levels (≥150 mg/dL) and established cardiovascular disease or diabetes mellitus with additional risk factors for cardiovascular disease 1.

Key differences between prescription omega-3 products and nonprescription fish oil supplements include:

  • FDA classification: Prescription drugs vs. dietary supplements
  • FDA-approved indication for treating elevated triglycerides: Yes for prescription products, no for supplements
  • Efficacy verification: Verified for prescription products, not for supplements
  • Content consistency and purity: Consistent and pure for prescription products, variable for supplements
  • Tolerability: Generally well-tolerated for prescription products, may cause gastrointestinal side effects for supplements

For patients requiring triglyceride reduction, prescription omega-3 fatty acid products, such as IPE (icosapent ethyl), are indicated as an adjunct to maximally tolerated statin therapy or diet to reduce triglyceride levels and ASCVD risk. IPE, an ethyl ester of EPA, has been shown to reduce the risk of myocardial infarction, stroke, coronary revascularization, and unstable angina requiring hospitalization in adult patients with elevated triglyceride levels and established cardiovascular disease or diabetes mellitus with additional risk factors for cardiovascular disease 1.

It's also important to note that while fish oil supplements may not provide the same cardiovascular benefits as prescription omega-3 products, eating fatty fish like salmon, mackerel, or sardines twice weekly can provide similar heart health benefits, according to recommendations from the American Heart Association 1. However, for specific conditions like high triglycerides, prescription omega-3 fatty acid products are preferred due to their proven efficacy and safety profile.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Fish Oil Benefits

  • Fish oil, which contains omega-3 fatty acids, has been shown to have several health benefits, including the reduction of triglyceride levels and the prevention of coronary heart disease 2, 3, 4.
  • The active ingredients in fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are responsible for its triglyceride-lowering effects 2, 5, 6.

Treatment of Hypertriglyceridemia

  • Prescription omega-3 fatty acids, which contain EPA and DHA, have been approved by the United States Food and Drug Administration for the treatment of very high triglyceride levels 2, 5, 6.
  • The recommended dose of EPA and DHA for triglyceride lowering is approximately 2-4 g/day 2, 6.
  • Fish oil products containing EPA and DHA are available without a prescription, but the American Heart Association advises that therapy with EPA and DHA to lower very high triglyceride levels should be used only under a physician's care 2, 5.

Safety and Efficacy

  • Prescription omega-3 fatty acids have been shown to be well tolerated, with a low rate of adverse events and treatment-associated discontinuations 2, 6.
  • The availability of prescription omega-3 fatty acids ensures consistent quality and purity, which is valuable for the medical management of hypertriglyceridemia 2, 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Fish oil supplementation: evidence for health benefits.

Cleveland Clinic journal of medicine, 2004

Research

Omega-3 fatty acids EPA and DHA: health benefits throughout life.

Advances in nutrition (Bethesda, Md.), 2012

Research

Overview of omega-3 Fatty Acid therapies.

P & T : a peer-reviewed journal for formulary management, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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