What is a DHA supplement and should you take one?

October 1, 2025 •

4 min read

Over 97% of the omega-3 fatty acids in the brain are comprised of DHA, highlighting its critical importance for cognitive function. A DHA supplement provides this essential omega-3 fatty acid, which is vital for brain, eye, and heart health throughout all life stages.

Quick Summary

This guide explains the function of docosahexaenoic acid (DHA), its key health benefits, common dietary sources, and how to select a high-quality supplement. It also outlines the differences between DHA and EPA to help you make an informed decision.

Key Points

Brain and Eye Health: DHA is a major structural component of the brain and retina, crucial for cognitive function and vision across all ages.
Maternal Support: During pregnancy and breastfeeding, DHA is essential for the healthy neurological and visual development of the infant.
Heart Health: Regular DHA supplementation can support cardiovascular health by helping to maintain healthy blood pressure and reducing triglyceride levels.
Anti-inflammatory Action: As an omega-3 fatty acid, DHA has anti-inflammatory effects that can aid in managing inflammation throughout the body.
Dietary Sources: Fatty fish like salmon and mackerel are excellent sources, while algal oil offers a reliable plant-based option for vegans.
EPA Comparison: While EPA focuses more on heart and joint health, DHA's primary benefits lie in brain and eye support, making the DHA:EPA ratio important for targeted benefits.

What is Docosahexaenoic Acid (DHA)?

Docosahexaenoic acid, or DHA, is a long-chain omega-3 polyunsaturated fatty acid. It serves as a major structural component in the brain and the retina of the eye, where it plays a critical role in nerve and cell membrane function. While our bodies can synthesize some DHA from other omega-3s like ALA (alpha-linolenic acid), the conversion rate is very low, making it necessary to obtain DHA directly from dietary sources or supplements.

The Health Benefits of a DHA Supplement

Supplementing your diet with DHA can offer a range of health benefits for different age groups.

Brain and Cognitive Function: As a primary building block for the brain, DHA supports memory, learning, and overall cognitive performance. Studies in healthy young adults with low dietary DHA intake have shown that supplementation can improve memory and reaction times. For older adults, adequate DHA intake is associated with reduced age-related cognitive decline.
Eye Health: DHA is a key component of the retina, making it essential for vision and overall eye health. Studies have shown that infants of mothers who supplemented with DHA during pregnancy had better early visual acuity than those who did not.
Cardiovascular Health: Omega-3s, including DHA, have a positive impact on heart health by helping to maintain healthy blood pressure and cholesterol levels. They can also help to lower blood triglyceride levels, which is a risk factor for heart disease.
Maternal and Fetal Health: During pregnancy and early childhood, DHA is crucial for the development of a baby's brain and nervous system. It is often included in prenatal vitamins and infant formulas to ensure adequate intake for optimal development. Adequate DHA during pregnancy is also linked to better neurodevelopmental health in children.
Anti-inflammatory Effects: DHA has potent anti-inflammatory properties and helps modulate the body's inflammatory response. This can be particularly beneficial for athletes and those with inflammatory conditions.

Dietary Sources of DHA

For those who prefer to get their nutrients from food, several dietary sources are rich in DHA:

Oily Fish: Fatty, cold-water fish are the best sources of DHA and EPA. Examples include salmon, mackerel, herring, sardines, and trout. The American Heart Association recommends eating two servings of fish per week.
Algae: Since fish get their omega-3s from eating microalgae, algal oil is a direct and excellent plant-based source of DHA. This is an ideal option for vegetarians and vegans.
Fortified Foods: Some food products, such as eggs, milk, and certain breads, are fortified with omega-3s, including DHA.

DHA vs. EPA: What's the Difference?

While both DHA and EPA are omega-3 fatty acids found in marine sources, they each have specialized functions within the body. Most quality supplements contain both, but their ratio can vary depending on the intended health benefit.


Feature	DHA (Docosahexaenoic Acid)	EPA (Eicosapentaenoic Acid)
Primary Role	Structural component of the brain and retina	Anti-inflammatory and cardiovascular benefits
Key Benefit Focus	Brain health, cognitive function, and vision	Heart health and inflammatory response
Brain Concentration	Most abundant omega-3 in the brain	Lower concentration in the brain compared to DHA
Recommended Ratio	Higher ratio for cognitive health	Higher ratio for heart and joint health
Dietary Source	Fatty fish, algae	Fatty fish, algae

How to Choose a DHA Supplement

When selecting a DHA supplement, consider the following factors to ensure you get a high-quality product:

Source: For a traditional option, look for fish oil from reputable brands that test for purity and contaminants like mercury. For a vegan alternative, choose a supplement derived from algae.
Form: DHA can come in various forms, including triglycerides (TG) and ethyl esters (EE). The triglyceride form is generally more readily absorbed by the body.
Purity and Quality: Reputable supplements will be third-party tested to ensure purity, potency, and freshness. Look for certifications like IFOS (International Fish Oil Standards).
Consultation: Always consult a healthcare professional for personalized guidance regarding dosage and suitability.

Conclusion

A DHA supplement can be a powerful tool for filling nutritional gaps, especially for those who don't consume sufficient amounts of oily fish or are vegan. Its role in brain and eye development, heart health, and anti-inflammatory support makes it a valuable addition to many dietary regimens. By understanding the benefits, sources, and how to choose a quality product, you can make an informed decision to support your overall wellness through DHA supplementation.

https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/

Frequently Asked Questions

A DHA supplement provides docosahexaenoic acid, an omega-3 fatty acid that is a major structural component of the brain and retina. These supplements are often derived from fish oil or algae and are used to support brain, eye, and heart health.

People who should consider taking a DHA supplement include pregnant or breastfeeding women, infants, children, those with cognitive concerns, and individuals who do not consume enough DHA-rich foods like fatty fish.

No, fish oil is not the only source. While fish oil is a common source, vegan and vegetarian-friendly DHA supplements are available and are derived from microalgae, which is the original source of omega-3s for fish.

Both are omega-3s, but DHA is primarily a structural component for the brain and eyes, while EPA is more known for its anti-inflammatory and cardiovascular benefits. Many supplements contain both, but the optimal ratio can depend on your health goals.

Adequate DHA intake is important during pregnancy and breastfeeding for the baby's development. Pregnant and breastfeeding women are often advised to ensure sufficient DHA intake, which can be achieved through diet or supplementation as recommended by a healthcare professional.

At moderate doses, side effects are usually mild and may include a fishy aftertaste, burping, or mild digestive upset. Higher doses may carry risks, and it's best to consult a healthcare provider, especially if you are on blood-thinning medication.

Look for third-party tested products to ensure purity, potency, and the absence of contaminants like mercury. Check the ingredient list for the specific amounts of DHA and EPA, and consider the source (fish oil or algae) based on your dietary needs.