Is it safe to take fish oil for a long time?: A long-term look at omega-3 supplementation

November 2, 2025 •

4 min read

According to a 2024 study, regular use of over-the-counter fish oil is widespread among older adults, often with the goal of improving heart health. This has raised the critical question: is it safe to take fish oil for a long time? The answer depends on individual health, potential side effects that may arise from extended use, and consulting with a healthcare professional.

Quick Summary

Long-term fish oil supplementation is generally considered safe at moderate levels but requires careful consideration of potential side effects and individual health status. Recent studies have highlighted both benefits for those with existing heart disease and potential risks for otherwise healthy individuals, particularly regarding atrial fibrillation.

Key Points

Moderate Intake Levels Are Generally Safe: Moderate levels of fish oil are generally considered safe for most adults, even long-term.
High Intake Levels Increase Bleeding Risk: Consuming high levels daily can increase the risk of bleeding and should be supervised by a doctor.
Atrial Fibrillation Concerns: Recent research suggests regular, long-term fish oil use may increase the risk of atrial fibrillation in healthy individuals, though it may benefit those with existing heart disease.
Source Matters: Eating fatty fish is the preferred method for getting omega-3s, as it provides additional nutrients and avoids potential supplement risks.
Side Effects Are Often Mild: Common side effects like fishy burps, upset stomach, or diarrhea can often be managed by taking supplements with food or splitting intake levels.
Personalized Medical Advice is Crucial: Certain individuals, including those on blood thinners or with diabetes, should always consult a doctor before starting or continuing long-term fish oil supplementation.

The role of omega-3s in your body

Fish oil is a rich source of the essential omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which the body cannot produce efficiently on its own. These fatty acids are crucial for overall health, playing a role in cellular function, brain health, and managing inflammation. This is why many people turn to supplements, especially if they don't consume fatty fish regularly.

Why consider long-term fish oil supplementation?

For some individuals and under medical supervision, long-term fish oil use offers established health benefits. These include:

Lowering high triglycerides: Prescription-grade omega-3 products are effective at significantly reducing very high triglyceride levels.
Managing inflammation: Omega-3s possess anti-inflammatory properties that can help manage chronic inflammation, which is linked to conditions like heart disease and arthritis.
Supporting joint health: Studies suggest that fish oil may help alleviate pain and stiffness associated with rheumatoid arthritis and could benefit people with osteoarthritis, especially if they are overweight.
Cardiovascular disease management: For individuals with pre-existing heart conditions, particularly those who have experienced heart failure or atrial fibrillation, long-term fish oil use has been shown to slow disease progression and reduce the risk of major cardiovascular events or death.

Potential risks and considerations for long-term use

While generally safe at recommended levels, exceeding recommended daily amounts of omega-3 fatty acids can increase the risk of certain side effects. Recent research also highlights nuanced risks, especially for otherwise healthy people.

Potential side effects of fish oil

Gastrointestinal issues: Common, mild side effects include burping, a fishy aftertaste, bad breath, heartburn, nausea, and diarrhea. Taking supplements with meals or in divided amounts can often mitigate these symptoms.
Increased bleeding risk: High levels of fish oil can have a blood-thinning effect, which might increase the risk of bruising and bleeding. This is particularly concerning for individuals taking anticoagulant or antiplatelet medications.
Elevated blood sugar: Some studies have observed that very high amounts of omega-3s may increase blood sugar levels in people with diabetes. However, findings on this topic are conflicting, and more research is needed.
Heart arrhythmia (Atrial Fibrillation): A large-scale 2024 study suggests that regular fish oil use might slightly increase the risk of developing atrial fibrillation (an irregular heartbeat) in people without prior cardiovascular disease. However, the same study indicated a beneficial effect for patients already diagnosed with the condition.
Vitamin A toxicity (from specific products): Certain fish oil products, particularly cod liver oil, are high in vitamin A. Excessive intake over time could lead to vitamin A toxicity, causing symptoms like nausea, joint pain, and, in severe cases, liver damage.

Fish oil vs. whole fish: a long-term comparison

Deciding between supplements and dietary sources for long-term omega-3 intake involves balancing convenience, intake levels, and potential contamination.


Feature	Fish Oil Supplements	Dietary Fish (e.g., salmon, mackerel)
Omega-3s (EPA/DHA)	Concentrated and standardized levels.	Variable amounts depending on the type and preparation.
Contaminants	Most high-quality supplements are purified to remove mercury and other contaminants.	Potential for mercury and PCB contamination, especially in larger, predatory fish.
Other Nutrients	Provides EPA and DHA, but often lacks the full nutrient profile of whole fish. Cod liver oil may provide extra vitamins A and D.	Contains a complete nutritional package, including lean protein, vitamins, and minerals.
Cost	Can be more cost-effective for obtaining concentrated omega-3s.	Cost varies greatly by fish type and preparation.
Intake Control	Easier to precisely control intake for therapeutic purposes, such as treating high triglycerides.	Intake is less precise and harder to control.

Who should consult a healthcare provider?

Before beginning long-term fish oil supplementation, especially at high levels, it is critical to consult a healthcare professional. This is particularly important for several groups:

Individuals on blood thinners: Due to the increased risk of bleeding, those taking anticoagulant medications like warfarin should be monitored closely.
Diabetics: High levels might affect blood sugar control.
Individuals with pre-existing heart conditions: While potentially beneficial for managing heart disease progression, new evidence suggests a higher risk of atrial fibrillation in the general population. Professional advice is necessary to weigh risks and benefits.
People allergic to seafood: Some individuals with seafood allergies may also react to fish oil supplements.
Pregnant or breastfeeding women: Specific guidelines exist, and products like cod liver oil with high vitamin A should be avoided.

Conclusion: Navigating long-term fish oil use responsibly

For many, long-term fish oil supplementation is a safe way to ensure adequate omega-3 intake, providing benefits for inflammation and overall health. However, the safety profile can be dependent on intake levels, and recent studies suggest that benefits may vary based on pre-existing health status, particularly concerning heart health. For individuals with heart disease, supplements can be beneficial, while for the general population, the potential risks of irregular heartbeats must be weighed against uncertain benefits. It is always best to prioritize omega-3 intake from dietary sources like fatty fish, and to use supplements under medical supervision, especially for high-level or prolonged regimens. Regular monitoring with a healthcare provider is essential to ensure the continued safety and appropriateness of your supplement routine.

Authoritative outbound link

For more detailed information on omega-3 fatty acids and their roles in health, consult the Mayo Clinic's comprehensive resource: Fish oil.

Frequently Asked Questions

Taking fish oil daily for an extended period, especially at moderate levels, is generally safe for most people and can help maintain steady levels of omega-3s in the body. However, daily intake of high levels over a long period may increase the risk of bleeding and could potentially lead to other issues, such as gastrointestinal side effects.

While recommendations vary, various health organizations provide guidance on typical daily intake levels of omega-3s. Always consult with a healthcare provider for personalized recommendations.

Recent studies show mixed results. For individuals with existing heart disease, fish oil may be beneficial. However, in otherwise healthy individuals, regular supplement use has been associated with a slightly increased risk of developing atrial fibrillation, an irregular heartbeat. Discuss these risks with your doctor, especially if you are taking high levels.

Getting omega-3s from dietary sources like fatty fish is generally preferable for long-term health, as it provides a broader range of nutrients. Supplements offer a concentrated amount, but whole fish provides a complete nutritional package. High-quality supplements are purified to remove mercury, a concern with some fish.

The most common and mild long-term side effects include gastrointestinal issues like heartburn, fishy burps, nausea, and loose stools. These can often be minimized by taking the supplement with food. Other potential risks, especially at high levels, include increased bleeding and effects on blood pressure.

Individuals on blood-thinning medications like warfarin should be cautious with long-term fish oil use, especially at high levels, as it can increase the risk of bleeding. Close medical supervision and regular blood monitoring are necessary in this case.

While unlikely with standard fish oil supplements, long-term use of certain products like cod liver oil could lead to vitamin A toxicity due to their high vitamin A content. Always check the vitamin A content on the label and follow instructions provided by a healthcare professional or the product packaging.