Does Marine Phytoplankton Contain EPA?

Yes. Certain species of marine phytoplankton produce EPA (eicosapentaenoic acid) at concentrations high enough to be nutritionally meaningful. But the word "certain" is doing real work in that sentence. Marine phytoplankton is a category covering thousands of organisms, and most of them are not EPA-rich. The species on the label determines whether you are getting a genuine omega-3 source or an expensive green powder with negligible fatty acids.

If you have picked up a product labelled "marine phytoplankton" expecting it to deliver EPA, your first job is to check which species it contains. A product built around Nannochloropsis gaditana will have a fundamentally different fatty acid profile from one containing Tetraselmis or Chlorella.

We chose Nannochloropsis for our ULTANA formulation precisely because of its EPA concentration. The species question is the single most important thing you can check on the label.

Which Phytoplankton Species Actually Contain EPA

The species that matters most for EPA supplementation is Nannochloropsis, a genus of marine eustigmatophytes. Published lipid analyses report EPA in N. gaditana ranging from 9 to 49 mg per gram of dry weight, constituting 15 to 46 per cent of total fatty acids depending on cultivation conditions.

That is not a minor variation. A product from a nutrient-stressed culture could deliver five times less EPA per gram than one grown under optimal conditions.

We grow this species in our closed photobioreactors and build our ULTANA Phytoplankton formulation around it. Published lipid analyses consistently show Nannochloropsis gaditana delivering the highest EPA concentration among commercially cultivated microalgae (Ma et al., 2016). The species decision was nutritional, not branding.

Phytoplankton Species That Do Not Provide EPA

Other microalgae used in supplements have very different fatty acid profiles, and the differences are not subtle. Schizochytrium, the most common source for algae oil capsules, produces DHA in abundance but very little EPA. Chlorella contains primarily ALA (a short-chain omega-3) rather than EPA. Spirulina contains negligible omega-3 of any kind.

If you are standing in a health shop comparing two products that both say "marine phytoplankton" or "algae omega-3," you could be comparing an EPA source with a protein supplement without realising it. The species name is what separates a meaningful claim from a meaningless one.

How Much EPA You Get from a Phytoplankton Supplement

This depends on the product format and the dose, and the distinction between formats matters more than most marketing acknowledges. Whole-cell Nannochloropsis powder contains EPA as part of the intact cell alongside protein, chlorophyll, carotenoids, and other naturally occurring nutrients. It is not a concentrated oil extract. The EPA per gram is lower than in a purified algae oil capsule, but it arrives in a whole-food matrix.

Open a tub of whole-cell phytoplankton powder and what you see is a fine, dark green substance with a faintly marine smell. Nothing like fish oil. That colour comes from the chlorophyll and carotenoid pigments that travel alongside the EPA in the intact cell. If you are used to the translucent yellow of a fish oil capsule, the visual difference tells you something real about the format.

The EFSA Threshold for EPA Heart Health Claims

There is one claim we can make with regulatory backing: EPA and DHA contribute to the normal function of the heart at a combined daily intake of 250 mg. That is an EFSA-authorised health claim under Commission Regulation (EU) No 432/2012. Whether a phytoplankton supplement meets this threshold depends on the serving size and the concentration.

We state the EPA content per serving on our product labels. Any EPA-containing supplement should do the same. If the label shows total omega-3 without breaking out EPA and DHA separately, you cannot evaluate what you are actually getting. Your body does not respond to adjectives like "omega-3 rich." It responds to milligrams.

Why the EPA Source Matters for Purity and Sustainability

Fish are the most familiar dietary source of EPA, but they do not produce it. They accumulate EPA by eating microalgae lower in the food chain. When you take a marine phytoplankton supplement containing Nannochloropsis, you are getting EPA from the organism that originally produced it.

This is a practical purity distinction, not a vague environmental argument. Fish oil carries a measurable risk of mercury and PCB contamination because those substances bioaccumulate in fish tissue over the animal's lifetime. Microalgae grown in closed photobioreactors are not exposed to those accumulation pathways. The EPA itself is chemically the same fatty acid regardless of source. The contaminant load is not.

Sustainability of Phytoplankton EPA vs Fish-Derived EPA

There is also a supply chain argument worth weighing. Global fish stocks are under documented pressure, and omega-3 demand continues to grow. Cultivated microalgae bypass the marine food chain entirely. You are not drawing from a depleted wild stock. You are growing the organism that produces the fatty acid directly.

That said, closed-system cultivation is energy-intensive and more expensive per gram of EPA than industrial fish oil production. If you are comparing prices at the till and wondering why phytoplankton costs more, the cultivation infrastructure is the primary reason. Cheaper is not necessarily worse, but the question worth asking is why something costs less.

EPA from Phytoplankton and What Else You Need

Nannochloropsis is EPA-dominant but not a significant source of DHA. If your goal is both EPA and DHA from plant sources, phytoplankton covers one half. For DHA, you need a dedicated algae oil supplement, typically from Schizochytrium. We produce both: ULTANA Phytoplankton for EPA and Clean Omega DHA for DHA.

The ALA Conversion Problem

If you are spooning ground flaxseed onto your porridge each morning and assuming that covers your omega-3 needs, the arithmetic is not in your favour. Flaxseed provides ALA, a short-chain omega-3 that your body must convert to EPA and DHA. Published estimates put that conversion rate at roughly 5-10%, varying by individual genetics and diet (Brenna et al., 2009).

This does not make flaxseed worthless. It means ALA is an inefficient route to the long-chain omega-3s your body actually uses for cardiovascular and inflammatory processes. Phytoplankton from Nannochloropsis provides EPA directly, skipping the conversion step.

Do You Need Both EPA and DHA?

Whether you need both depends on your overall diet and what your GP recommends. Most health authorities recommend getting both EPA and DHA. If your current fish oil provides both and you are switching to plant sources, you would need a phytoplankton supplement for EPA and an algae oil for DHA. We cover the full distinction in our guide to what DHA is and where to find it.

How to Check Whether Your Supplement Contains Meaningful EPA

If you are scrolling through product pages or reading labels in a health shop, three things are worth checking before you spend your money.

Species name. A supplement that says "marine phytoplankton" without naming the species is asking you to trust a category label. For EPA content, look for Nannochloropsis on the label. If the species is not stated, you cannot evaluate what you are buying. Silence on this point is itself informative.

Cultivation method. Closed photobioreactor or open pond? If the product page does not say, ask. The answer affects both purity and consistency. Most reputable producers will state their method clearly because it is a genuine differentiator.

EPA per serving in milligrams. Look for a quantified figure on the nutritional information panel, not vague references to "omega-3 rich" or "nutrient dense." If a product does not declare its EPA content per dose, you cannot meaningfully compare it to anything else on the shelf. We declare ours because we think you deserve to do the arithmetic.

EPA in Marine Phytoplankton FAQ

Is EPA from phytoplankton absorbed as well as EPA from fish oil?

The EPA in Nannochloropsis is present in a phospholipid-bound form, which some research suggests may be well-absorbed. However, we do not yet have the large, controlled human trials at equivalent doses that would let us claim superior or equivalent absorption with full confidence. The evidence is encouraging but still developing. If you are comparing products across formats, be cautious about assuming milligram-for-milligram equivalence.

Can phytoplankton EPA replace fish oil?

It can replace the EPA component of fish oil, but not the DHA. If your current fish oil provides both EPA and DHA, switching to phytoplankton alone would leave a gap. You would need a separate algae-derived DHA supplement to cover both fatty acids from plant sources.

Does phytoplankton taste like fish?

No. Phytoplankton has a mild, slightly vegetal flavour, noticeably different from fish oil. Fish oil develops its strong taste through oxidation during processing and storage. If you have experienced the reflux that fish oil capsules sometimes cause, most people find phytoplankton far more tolerable.

Is it safe to take phytoplankton EPA every day?

For Nannochloropsis at recommended supplement doses, daily use is well-established. Check with your GP if you are pregnant, breastfeeding, or taking blood-thinning medication. EPA can have mild anticoagulant effects at high intakes, generally above 2-3 g of combined EPA and DHA daily, though standard phytoplankton supplement doses are well below this threshold.

How much phytoplankton do you need for a meaningful EPA dose?

That depends on the EPA concentration per serving of your specific product. The EFSA-authorised heart health claim applies at a combined 250 mg of EPA and DHA daily. Check the nutritional information panel for the actual EPA content per dose, then work out whether you are meeting that threshold from your chosen product alone or in combination with other sources like oily fish or algae oil.

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Consult your GP before starting any supplement.

Methodology and Disclosure

Phytality manufactures marine phytoplankton supplements from Nannochloropsis gaditana grown in closed photobioreactors. We have a direct commercial interest in this ingredient. Taxonomic descriptions and fatty acid profile comparisons reflect published literature cited above. The EFSA-authorised health claim for EPA and DHA is cited under Regulation EU 432/2012 with its intake condition stated.

ALA conversion rates are drawn from Brenna et al. (2009). Bioavailability of EPA from whole-cell Nannochloropsis is an area of active research; we have noted the current limitations of the evidence.

Last reviewed: March 2026. Next review due: March 2027.