Walk into any supplement store and you'll see dozens of fish oil products advertising EPA, DHA, or both.

But what do these letters actually mean?

Although EPA and DHA are both omega-3 fatty acids, they serve different roles throughout the body. Understanding these differences can help you choose a supplement that better matches your health goals.

Whether you're looking to support your heart, brain, joints, mood, pregnancy, or athletic recovery, knowing the difference between EPA and DHA can make your supplement choice much easier.

What Are EPA and DHA?

EPA stands for eicosapentaenoic acid, while DHA stands for docosahexaenoic acid.

Both are long-chain marine omega-3 fatty acids naturally found in:

• Salmon
• Sardines
• Anchovies
• Mackerel
• Herring
• Krill
• Algae (vegetarian source)

Unlike plant omega-3s (ALA), which must be converted into EPA and DHA by the body, marine sources provide these beneficial fats in their active forms. Human conversion of ALA into EPA and especially DHA is relatively inefficient. (Office of Dietary Supplements)

EPA vs DHA: The Biggest Differences

EPA	DHA
Primarily supports inflammation balance	Primary structural fat in the brain and retina
Strong evidence for cardiovascular support	Essential for brain and eye health
Often emphasized for joint comfort	Critical during pregnancy and infancy
May support mood and emotional wellbeing	Supports cognition and memory
Frequently used in higher amounts for inflammation-focused formulas	Naturally found in high concentrations within nerve tissue

Think of it this way:

• EPA helps regulate many of the body's signaling pathways involved in inflammation.
• DHA helps build and maintain the structure of the brain, eyes, and nervous system.

Both are important, but they perform different jobs.

Benefits of EPA

EPA is best known for helping the body produce specialized molecules that help resolve inflammation rather than simply suppress it. These specialized pro-resolving mediators (SPMs) play an important role in returning tissues to a healthy state after inflammation. (PubMed)

Research suggests EPA may help support:

• Cardiovascular health
• Healthy triglyceride levels
• Joint comfort
• Exercise recovery
• Mood support
• Healthy inflammatory balance

Many clinical studies evaluating cardiovascular health have focused on EPA because of its effects on triglycerides and vascular function. (PubMed)

Benefits of DHA

DHA is the most abundant omega-3 fat in the brain and retina.

Approximately 25 to 40 percent of the polyunsaturated fats in the brain consist of DHA, making it essential for normal nervous system function. (Office of Dietary Supplements)

DHA supports:

• Brain development
• Memory
• Learning
• Eye health
• Nervous system function
• Healthy aging
• Pregnancy and fetal development

Because of its structural role, DHA requirements increase during pregnancy and breastfeeding to support fetal brain and eye development. (Office of Dietary Supplements)

Which Is Better for Heart Health?

The answer is both.

EPA and DHA each contribute to cardiovascular health, but they appear to influence different risk factors.

Research suggests:

• Both lower triglycerides.
• DHA may produce slightly greater triglyceride reductions.
• DHA may reduce resting heart rate and blood pressure more than EPA.
• EPA has been extensively studied for cardiovascular risk reduction in certain high-risk populations. (PubMed)

Rather than viewing one as "better," many experts recommend obtaining both unless a healthcare professional advises otherwise.

Which Is Better for Brain Health?

When it comes to the brain, DHA takes center stage.

DHA is incorporated directly into brain cell membranes where it helps maintain membrane fluidity, communication between neurons, and normal cognitive function.

EPA still plays an important supporting role by helping regulate inflammatory signaling that may influence brain health and mood. (PubMed)

Do You Need More EPA or More DHA?

The ideal ratio depends on your health goals.

Higher EPA formulas may be preferred for:

• Healthy inflammatory balance
• Joint support
• Mood support
• Cardiovascular support

Higher DHA formulas may be preferred for:

• Pregnancy
• Brain health
• Eye health
• Cognitive support
• Infant development

For general wellness, many high-quality fish oils contain a balanced combination of both EPA and DHA.

Choosing a High-Quality Omega Supplement

When comparing products, look for:

• Clearly listed EPA and DHA amounts
• Third-party testing for purity and potency
• Low oxidation (fresh oil)
• Sustainable sourcing
• Appropriate dosage for your goals

If you're unsure how to identify a quality product, read our guide:

How to Choose a High-Quality Omega Supplement

The Bottom Line

EPA and DHA are both essential omega-3 fatty acids, but they are not interchangeable.

EPA primarily supports healthy inflammatory signaling, cardiovascular function, and exercise recovery, while DHA is the primary structural omega-3 found in the brain, eyes, and nervous system.

For most people, the best approach isn't choosing one over the other. Instead, focus on a high-quality omega-3 supplement that provides meaningful amounts of both EPA and DHA and matches your individual health goals.

References

1. National Institutes of Health Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals.
2. Abdelhamid AS, et al. The differential effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular risk factors: An updated systematic review of randomized controlled trials. Prostaglandins Leukot Essent Fatty Acids. 2024.
3. Schuchardt JP, et al. Bioavailability of EPA and DHA in humans: A comprehensive review. Prog Lipid Res. 2025.
4. European Food Safety Authority (EFSA). Scientific Opinion on the Tolerable Upper Intake Level of EPA, DHA and DPA. 2012.
5. Alsharairi NA, et al. Role of the EPA:DHA dosing ratio in omega-3 supplements on blood fatty acid profiles and inflammation: A systematic review and meta-analysis. 2025.