Which Algae Is Rich in EPA and DHA? Your Guide to Microalgal Omega-3

December 17, 2025 •

4 min read

Did you know that fish get their omega-3s, including EPA and DHA, from the algae they consume? This establishes algae as the original and most sustainable source of these vital fatty acids, making many people wonder: which algae is rich in EPA and DHA?

Quick Summary

Microalgae are the primary producers of essential omega-3 fatty acids EPA and DHA, offering a sustainable alternative to fish oil. Species like Schizochytrium are cultivated for high DHA content, while Nannochloropsis is known for high EPA levels. Modern cultivation techniques can produce nutritionally balanced oils.

Key Points

DHA Source: The heterotrophic microalga Schizochytrium sp. is a leading commercial source of DHA, with up to 50% of its total fatty acids being DHA.
EPA Source: The photoautotrophic microalga Nannochloropsis sp. is widely cultivated and marketed for its high concentration of EPA.
Balanced Omega-3s: Through advanced co-cultivation techniques, a single microalgal biomass can be produced with a balanced 1:1 ratio of DHA and EPA.
Superior to Fish Oil: Microalgae oil provides omega-3s directly from the primary producers, avoiding ocean-based contaminants and offering a sustainable, ethical, and pure alternative.
Not all Algae are Equal: Common superfoods like spirulina and chlorella, while nutritious, are not typically rich in the specific EPA and DHA required for optimal human health compared to specialized cultivated strains.
Controlled Production: Growing microalgae in closed bioreactors allows for a consistent, high-quality, and clean product free from environmental toxins.

The search for sustainable, plant-based sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) leads directly to microalgae—the original producers of these beneficial omega-3 fatty acids. As awareness of environmental and health concerns associated with fish oil grows, targeted cultivation of specific microalgal species has emerged as a superior alternative for supplements and food fortification.

Leading the Way: Algae Species Rich in Omega-3s

While many people associate algae with seaweeds like spirulina or chlorella, these are often not the most efficient sources for concentrated EPA and DHA. Specialized microalgae, grown in controlled environments, produce much higher concentrations. The key species depend on whether you are seeking an oil rich in DHA, EPA, or a balanced combination.

DHA-Rich Microalgae

Species known for their exceptionally high DHA content are primarily marine heterotrophs. Heterotrophic growth means they don't rely on light for energy but instead consume organic carbon sources, allowing for rapid lipid accumulation in bioreactors.

Schizochytrium sp.: This genus of heterotrophic microalgae is arguably the most recognized industrial source of DHA. Cultivated in large, sterile bioreactors, Schizochytrium sp. can accumulate lipids where DHA constitutes 35-50% of the total fatty acids. Its oil offers a pure, vegan, and environmentally friendly alternative to fish oil and is commonly used in infant formulas and nutritional supplements.
Crypthecodinium cohnii: Another marine heterotroph, C. cohnii, is also valued for its high DHA yield. It has the unique advantage of producing almost exclusively DHA, with only trace amounts of other polyunsaturated fatty acids. This makes the extraction process more straightforward for isolating high-purity DHA. Commercial production methods have been optimized to maximize DHA output.

EPA-Rich Microalgae

For those seeking a pure source of EPA, certain photoautotrophic species—those that use sunlight for energy—are the frontrunners. Some, like Nannochloropsis, are already in commercial use.

Nannochloropsis sp.: This group of microalgae is celebrated for accumulating high levels of EPA. Species like Nannochloropsis oculata are cultivated in controlled conditions to produce oil with over 24% EPA content. Some supplements derived from Nannochloropsis are even formulated to contain exclusively EPA, which has shown distinct cardiovascular benefits without affecting LDL cholesterol in the same way as combined EPA/DHA supplements.
Microchloropsis salina: Formerly classified under Nannochloropsis, Microchloropsis salina also demonstrates strong EPA production. Research shows it accumulates high EPA concentrations, particularly under nutrient-saturated conditions, and can be used in co-cultivation strategies to achieve a balanced EPA/DHA profile.
Phaeodactylum tricornutum: This marine diatom can accumulate high levels of EPA, especially when cultured under specific conditions like low temperature. While its natural DHA production is lower, genetic engineering has successfully augmented its endogenous fatty acid pathway to increase DHA content significantly.

The Innovation of Co-Cultivation

Traditionally, a single microalgae strain produces either primarily EPA or primarily DHA, but not both in significant, balanced quantities. However, recent biotechnological advances have enabled the co-cultivation of multiple species to achieve a combined, nutritionally optimal oil.

Research has successfully demonstrated the co-cultivation of DHA-producer Tisochrysis lutea with EPA-producer Microchloropsis salina in controlled photobioreactors.
This process resulted in a balanced DHA:EPA ratio of almost 1:1 in the harvested biomass.
Interestingly, co-cultivation not only provides a nutritionally superior product but can also increase total biomass and DHA content compared to monocultures, potentially due to enhanced light spectrum utilization by the combined species.

Microalgae vs. Fish Oil: A Comparative Analysis

Microalgae oil is increasingly viewed as a superior and more sustainable source of omega-3s than fish oil. The following table highlights the key differences.


Feature	Microalgae Oil	Fish Oil
Source	Primary producers of omega-3s	Secondary source; fish accumulate omega-3s by eating microalgae
Sustainability	Highly sustainable, requires minimal water and no arable land, no pressure on marine ecosystems	Unsustainable; contributes to overfishing and depletion of wild fish stocks
Contaminants	Grown in controlled environments, free from mercury, heavy metals, microplastics, and other pollutants	Potential for contamination from pollutants concentrated up the marine food chain
Product Purity	Can be produced as pure DHA-only, EPA-only, or balanced blends	Varies widely based on fish species and source
Flavor	Typically has a neutral flavor profile, avoiding unpleasant fishy aftertaste	Can have a strong fishy taste and burps
Bioavailability	Bioavailability is comparable to fish oil	Well-studied, but bioavailability can be influenced by processing

The Algae Oil Extraction Process

The journey from microalgae to a finished supplement involves a specialized and highly controlled process. After the algae are grown to high density in bioreactors, they are harvested and processed to extract the omega-3 rich oil. Techniques for extraction and purification, such as solvent-free methods, ensure a high-quality, stable, and pure final product. Advances in genetic engineering also allow for targeted enhancements of specific fatty acid yields, further optimizing the process.

Conclusion: Microalgae Lead the Omega-3 Revolution

Microalgae offer a highly promising, sustainable, and pure source of both EPA and DHA. For those seeking DHA, heterotrophic microalgae like Schizochytrium and Crypthecodinium cohnii are excellent sources. For EPA, species such as Nannochloropsis are the top choice. Modern biotechnology, including co-cultivation techniques, can even produce balanced EPA/DHA blends from different microalgae species simultaneously. As demand for plant-based and eco-friendly nutrition increases, algae oil is set to become the standard for high-quality omega-3 supplementation, offering superior purity and environmental benefits over traditional fish-based products. The science is clear: the future of omega-3s comes from the base of the marine food chain, not the top.

For more detailed information on specific cultivation methods and research, refer to authoritative scientific journals like those found on the National Institutes of Health website, such as articles discussing EPA and DHA production via microalgae like Nannochloropsis.

Frequently Asked Questions

Algae are the original and primary producers of EPA and DHA. Fish oil accumulates these fatty acids by eating algae and smaller fish, which risks concentrating heavy metals and other marine pollutants. Algae cultivated in controlled environments are grown cleanly, providing a purer, more sustainable, and ethical omega-3 source.

DHA and EPA are both omega-3 polyunsaturated fatty acids with distinct roles. DHA is crucial for brain development, cognitive function, and eye health. EPA has strong anti-inflammatory properties and supports cardiovascular health. A balance of both is often recommended for comprehensive health benefits.

While spirulina and chlorella are nutrient-dense superfoods, they are generally poor sources of preformed EPA and DHA compared to specialized microalgae like Schizochytrium and Nannochloropsis. They contain primarily ALA, which the human body converts to EPA and DHA inefficiently.

The cultivation occurs in large, controlled bioreactors, which are sterile and enclosed systems, often using non-arable land and non-potable water. This process is highly efficient and sustainable, allowing for precise control over the algae's growth conditions to maximize omega-3 production.

Some individual species, like Tisochrysis lutea, produce both EPA and DHA. However, in modern biotechnology, co-cultivating different strains—such as a DHA-rich algae with an EPA-rich algae—has been successfully used to produce a single, nutritionally balanced biomass rich in both fatty acids.

No, high-quality algae oil is cultivated in a controlled, clean environment and purified, giving it a neutral taste and odor. This is in contrast to some fish oils, which can suffer from unpleasant fishy tastes and burps due to oxidation and contaminants.

Initial production costs can be higher due to specialized equipment and processes. However, as demand increases and technology advances, the price is becoming more competitive. Many consumers value the benefits of purity, sustainability, and vegan sourcing enough to justify the cost.