Does Fish Oil Lower Triglycerides? What You Need to Know

October 5, 2025 •

3 min read

High triglycerides are a significant risk factor for heart disease and are becoming increasingly common, with over 25% of U.S. adults having elevated levels. A wealth of research indicates that the omega-3 fatty acids found in fish oil can play a crucial role in managing these fats. For individuals seeking to understand options for managing their lipid levels, understanding how fish oil might impact triglycerides is essential.

Quick Summary

This article explores the mechanisms by which fish oil may influence blood triglycerides, distinguishing between different types of supplements. It details potential benefits and side effects and compares fish oil with other approaches for managing hypertriglyceridemia.

Key Points

Potential for Influence: Research suggests fish oil, particularly the omega-3 fatty acids EPA and DHA, can play a role in managing triglyceride levels.
Mechanism of Action: Fish oil is believed to influence triglyceride levels by impacting the liver's production of VLDL and potentially increasing the activity of enzymes that clear triglycerides from the blood.
Different Options Available: OTC supplements offer varying amounts of omega-3s, while prescription options provide standardized, higher concentrations, and the choice depends on individual needs and medical advice.
Lifestyle Integration: Incorporating fish oil or omega-3s from food is often part of a broader strategy that includes a healthy diet, exercise, and other lifestyle modifications for managing lipid levels.
Medical Consultation is Vital: Always consult with a healthcare provider before using fish oil, especially for high triglyceride levels, to determine if it is appropriate and to discuss any potential interactions with other medications.
Forms of Omega-3s: Both EPA and DHA are important omega-3 fatty acids, and some specialized prescription formulations may contain predominantly EPA, which has been studied for its effects on cardiovascular health.
Possible Side Effects: Like many supplements, fish oil can cause mild side effects such as digestive upset or fishy aftertaste. Discuss any concerns with your doctor.

The Science Behind Fish Oil and Triglyceride Management

Fish oil's potential to influence triglyceride (TG) levels is supported by clinical research. The active components believed to be responsible for this effect are the long-chain omega-3 polyunsaturated fatty acids (PUFAs), primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The effectiveness can depend on the specific omega-3 components and the amount consumed.

Fish oil is thought to influence plasma TG levels by impacting the liver's production and the body's clearance of TG-rich lipoproteins.

Reduced Liver Production: Omega-3 fatty acids, particularly EPA, are believed to decrease the liver's production of very low-density lipoprotein (VLDL). They may activate proteins that inhibit lipid synthesis in the liver, potentially reducing materials for VLDL production.
Enhanced Triglyceride Clearance: Fish oil may help clear TG from the bloodstream by influencing the activity of lipoprotein lipase (LpL), an enzyme that breaks down triglycerides for tissue absorption. Studies suggest fish oil can impact LpL activity.
Other Mechanisms: Research indicates fish oil may have anti-inflammatory properties, and inflammation can sometimes be associated with high triglycerides. Some studies suggest omega-3 compounds may also influence intestinal fat absorption.

Over-the-Counter vs. Prescription Options

While OTC fish oil may offer some benefits, prescription-strength options are sometimes considered for clinically high triglycerides.

Comparison of Fish Oil Options


Feature	Over-the-Counter (OTC) Supplements	Prescription Omega-3 Medications
Potency	Lower, often inconsistent EPA/DHA concentration.	High, standardized concentrations (EPA/DHA or EPA-only).
Dose	Generally contains lower amounts of EPA+DHA.	Typically provides a specific, higher amount for therapeutic effect.
Regulation	Not strictly FDA regulated; purity varies.	FDA regulated and approved; purity verified.
Efficacy	May have modest effects; may not be sufficient for therapeutic management of significantly elevated levels.	Proven to significantly influence very high triglycerides.
Key Examples	Generic fish oil, krill oil.	Medications containing high-purity omega-3 fatty acids, such as those with EPA or EPA+DHA.
Use Case	General health support, mild lipid management.	Sometimes recommended for severe hypertriglyceridemia (TG ≥ 500 mg/dL) or those at high cardiovascular risk, under medical supervision.

Considering Higher Needs

For very high triglycerides (over 500 mg/dL), medical guidelines sometimes suggest prescription-strength omega-3 medication. Clinical trials indicate that prescription omega-3s can significantly influence triglyceride levels. For borderline-high (150-199 mg/dL) or high (200-499 mg/dL) levels, management strategies are typically discussed with a doctor.

Practical Considerations for Omega-3s

Consult Your Doctor: Speak with your healthcare provider before starting any supplement, especially with existing conditions or medications, to discuss suitability and check for contraindications.
Choose Appropriately: Discuss if a purified, pharmaceutical-grade product or OTC supplement is appropriate for your needs. For very high levels, medical guidance is typically needed.
Ensure Quality and Purity: For OTC supplements, consider looking for third-party testing (USP, NSF) for purity and potency.
Pair with Healthy Lifestyle Choices: Omega-3 intake is most effective when combined with regular exercise, limiting sugar/refined carbs, and a balanced diet. Oily fish are also excellent sources.

Conclusion

Fish oil is recognized for its potential role in managing triglycerides, particularly at the levels found in prescription formulations. It is believed to influence liver VLDL production and improve TG clearance. While quality OTC supplements may offer benefits, prescription-grade options are sometimes considered necessary for clinically elevated levels under medical supervision. A personalized approach with medical guidance and healthy habits is key for supporting healthy triglyceride levels and heart health.

Learn More About Omega-3s

For further information on omega-3 fatty acids and their health implications, you may visit the National Institutes of Health Office of Dietary Supplements website.

Frequently Asked Questions

Changes in triglyceride levels can often be observed within a few weeks to months with consistent use, especially at the amounts found in prescription formulations. Clinical studies often evaluate outcomes after several weeks of treatment.

For very high triglycerides (levels significantly above the normal range), healthcare professionals often recommend prescription-strength omega-3 medications due to their higher, regulated concentrations. OTC supplements may not provide sufficient amounts for this purpose.

Fish oil's primary effect is on triglycerides. It may also have a modest positive effect on 'good' HDL cholesterol. However, some studies on certain omega-3 formulations have shown a potential for a slight increase in 'bad' LDL cholesterol.

For clinically elevated levels, medical professionals may recommend a prescription-grade omega-3 medication containing specific amounts of high-purity EPA or a combination of EPA and DHA. The best approach is determined in consultation with your doctor.

Common, usually mild, side effects can include fishy burps, bad breath, heartburn, nausea, and diarrhea. Discuss any concerns with your healthcare provider, especially as potential risks can vary depending on individual health factors.

Healthcare providers might discuss amounts of combined EPA and DHA that are higher than typically found in standard dietary intake when addressing elevated triglycerides. The appropriate amount is determined by a doctor based on individual needs.

While a diet rich in oily fish and low in refined sugars and carbohydrates is beneficial for heart health, it is often challenging to achieve the level of omega-3 intake needed to significantly lower very high triglycerides through food alone. Supplements are frequently considered necessary in these cases, always under medical supervision.