What Happens If We Take Fish Oil Capsules Every Day? A Comprehensive Look at the Effects

January 11, 2026 •

5 min read

Over 7% of U.S. adults reported taking omega-3 supplements, which includes fish oil, in 2021. The question of what happens if we take fish oil capsules every day is common, and the answer involves a balanced look at both the significant health benefits and potential drawbacks of this popular wellness habit.

Quick Summary

Taking daily fish oil can offer long-term benefits for cardiovascular, brain, and joint health due to its omega-3 content. It may also lead to mild side effects, such as digestive issues, especially at higher doses. Purity, dosage, and potential interactions with other medications should be considered for safe supplementation.

Key Points

Long-Term Consistency: Daily fish oil is most effective over months or years for building up omega-3 levels for heart, brain, and joint benefits.
Not a 'Wonder Drug': While beneficial, especially for reducing triglycerides and inflammation, scientific evidence shows mixed results for some claimed benefits like preventing heart attacks in healthy individuals.
Common Side Effects: Mild digestive issues such as burping, nausea, and loose stools are common, especially at higher doses.
Bleeding Risk: High doses (over 3g daily) can increase the risk of bleeding and may interact with blood-thinning medications.
Beware of Contaminants: Always choose a high-quality, reputable brand that is third-party tested to ensure purity and avoid contaminants like mercury.
Atrial Fibrillation Concern: Recent studies have associated high doses of fish oil with an increased risk of atrial fibrillation, an irregular heart rhythm, particularly in those with pre-existing heart conditions.

What is Fish Oil and Why Do We Take It?

Fish oil is a dietary supplement derived from the tissues of oily fish like salmon, mackerel, and tuna. It is a rich source of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential for human health but cannot be produced efficiently by the body. These fatty acids are crucial components of cell membranes and play a vital role in various bodily functions, including those of the brain, heart, and immune system. While many health organizations recommend consuming fatty fish twice a week, supplementation offers a convenient alternative for many people.

The Potential Benefits of Taking Fish Oil Daily

Long-term, daily supplementation with fish oil can yield a range of health benefits, supported by a body of scientific research. The most significant effects are observed over sustained periods, rather than immediately.

Cardiovascular Health

Lowers triglycerides: Fish oil is effective at reducing very high triglyceride levels in the blood, which is a key risk factor for heart disease.
Reduces blood pressure: Daily intake may cause a modest but significant reduction in blood pressure, especially in individuals with moderate to high blood pressure.
Supports overall heart function: Omega-3s protect heart tissue and help prevent irregular heartbeats.

Brain and Mental Health

Enhanced cognitive function: The DHA in fish oil is a major structural component of the brain and is vital for optimal function. While results are mixed, some studies suggest benefits for mild memory loss and cognitive decline.
Improved mood: Research indicates that omega-3s may help reduce symptoms of depression and anxiety, and can be used as a complementary therapy alongside conventional treatments.
Fetal development: Pregnant women are encouraged to take fish oil, as the DHA is critical for the proper brain and nervous system development of the fetus.

Anti-Inflammatory Effects

Reduces inflammation: Omega-3 fatty acids have potent anti-inflammatory properties that can help combat chronic inflammation, a known contributor to several diseases.
Manages rheumatoid arthritis: Daily intake can help reduce joint tenderness, swelling, and morning stiffness associated with rheumatoid arthritis.

Skin, Eye, and Other Benefits

Supports skin health: Fish oil can help hydrate the skin, reduce irritation from conditions like psoriasis and eczema, and contribute to a healthier complexion.
Protects eye health: Regular consumption can help prevent age-related macular degeneration (AMD) and soothe dry eye symptoms.
Aids in weight management: Some studies suggest that fish oil can help reduce body fat and appetite, especially when combined with exercise.

Potential Side Effects and Risks

While generally safe, especially at recommended doses, daily fish oil intake can have potential side effects and risks, particularly with higher doses.

Common Side Effects

Digestive issues: Some of the most frequently reported side effects include burping (with a fishy aftertaste), heartburn, nausea, and loose stools. Taking capsules with meals or freezing them can help mitigate these symptoms.
Bad breath: The fishy taste can sometimes lead to bad breath or unpleasant-smelling sweat.

More Serious Risks

Increased risk of bleeding: High doses (typically over 3 grams daily) can have a blood-thinning effect, which may be dangerous for individuals on anticoagulant medications like warfarin or those with bleeding disorders.
Low blood pressure: For those without high blood pressure, or those already on medication, fish oil's blood-pressure-lowering effect could cause issues.
Vitamin A toxicity: Some fish oils, particularly cod liver oil, contain high levels of vitamin A. Consuming excessive amounts can lead to vitamin A toxicity, causing symptoms like dizziness and potentially liver damage over time.
Increased risk of atrial fibrillation: A study published in BMJ Medicine suggests that regular, high-dose fish oil use may increase the risk of atrial fibrillation, an irregular heart rhythm, in people with existing cardiovascular conditions.

Comparison: Benefits vs. Risks of Daily Fish Oil


Aspect	Benefits of Daily Fish Oil	Risks of Daily Fish Oil
Cardiovascular	Reduced triglycerides, lower blood pressure, improved heart function.	Increased risk of atrial fibrillation (for those with existing heart issues), potential for low blood pressure.
Brain Health	Better mood and cognitive function, supports fetal development.	Minimal risks at standard doses; very high doses might cause insomnia in some.
Inflammation	Reduced chronic inflammation, relief for rheumatoid arthritis symptoms.	None directly related to anti-inflammatory benefits; standard side effects may apply.
Digestive System	None.	Burping, nausea, heartburn, diarrhea.
Safety	Generally safe at standard doses (up to 3 grams EPA+DHA).	Increased bleeding risk at high doses, interactions with some medications, potential contaminants in low-quality products.

Long-Term Consistency and Quality

For most individuals, the key to beneficial daily fish oil supplementation is consistency over time and using a high-quality product. The most substantial health outcomes, such as reduced inflammation and improved cognitive function, are typically seen after months or even years of steady intake, not after just a few days. The long-term use is generally considered safe as long as the daily dose is not excessive (typically under 3 grams of EPA and DHA combined) and the supplement is from a reputable source. Reputable brands undergo third-party testing to ensure the product is free from contaminants like mercury, which binds to proteins in fish meat rather than the oil.

It is always wise to consult with a healthcare provider before starting any new supplement, especially for those with existing health conditions or who are taking other medications. For instance, fish oil can interact with blood thinners and blood pressure medications. Your doctor can help determine the right dosage and ensure it aligns with your overall health plan. For those who cannot or prefer not to take fish oil capsules, consuming fatty fish twice a week remains an excellent way to get omega-3s.

Conclusion

Taking fish oil capsules every day can lead to a multitude of health benefits, particularly in supporting heart, brain, and joint health, largely due to its anti-inflammatory omega-3 fatty acids. However, these benefits are maximized with consistent, long-term use. While minor side effects like digestive upset are common, more serious risks like increased bleeding are primarily associated with high doses or specific pre-existing conditions. By choosing a high-quality supplement and discussing dosage with a healthcare professional, individuals can safely incorporate daily fish oil into their routine and reap its many rewards.

National Center for Complementary and Integrative Health: Omega-3 Supplements

Choosing a Quality Supplement

Not all fish oil supplements are created equal. When selecting a product for daily use, look for supplements that specify the amounts of EPA and DHA, as these are the most beneficial omega-3s. Additionally, check for third-party quality certifications, which indicate that the product has been tested for purity and potency, confirming it is free from harmful contaminants like mercury and PCBs. Products with enteric coatings can also help reduce the common side effect of a fishy aftertaste or burps.

The Role of Dosage

The appropriate dosage of fish oil depends on individual health goals. Standard recommendations often suggest between 250–500 mg of combined EPA and DHA per day for general health. Higher doses, up to 3,000 mg daily, are often considered safe for adults, but this should always be discussed with a doctor, especially when targeting specific conditions like very high triglycerides, for which prescription-strength formulations exist. Exceeding 3 grams per day is not recommended without medical supervision due to the increased risk of side effects.

Frequently Asked Questions

Yes, taking fish oil capsules daily is generally considered safe for most healthy adults, as long as the dosage does not exceed recommended amounts (typically 3 grams of EPA+DHA per day). It is important to consult a healthcare provider to determine the right dose for your individual needs.

Missing a single day of fish oil will not negate the benefits. The positive effects of fish oil accumulate over weeks, months, and years of consistent use, so the occasional missed dose will have a minimal impact on your long-term health.

You can take fish oil at any time of day, but taking it with a meal containing dietary fat maximizes absorption. For those who experience a fishy aftertaste, taking it with a larger meal like lunch or dinner can help. Splitting the dose between morning and night may also reduce digestive side effects.

While some benefits like reduced inflammation may start within a few weeks, most significant effects, such as lowering triglycerides or improving cognitive function, are associated with long-term use over several months or even years.

High doses of fish oil (over 3 grams daily) can slow blood clotting and may increase the risk of bleeding, especially for people already on blood-thinning medication. You should always talk to your doctor before taking high doses or if you are on other medications.

Individuals allergic to seafood, those with bleeding disorders, people on blood-thinning medications, and those with certain heart conditions like atrial fibrillation should be cautious. Pregnant or breastfeeding women and those with bipolar disorder should also consult a doctor.

Eating fatty fish (like salmon) is often recommended as the primary source of omega-3s, providing other nutrients like protein and minerals. However, fish oil supplements offer a convenient way to ensure consistent omega-3 intake, particularly for those who don't eat fish regularly. Supplements are also purified to remove contaminants like mercury found in some fish meat.

For most people, daily fish oil does not raise blood sugar. Some studies suggest very high doses might affect glucose levels in people with diabetes, but other research is conflicting. People with diabetes should monitor their blood sugar and consult their doctor before starting.