Marine Phytoplankton Nutrition Facts

The nutritional profile of a marine phytoplankton supplement depends almost entirely on the species inside it. Most products use Nannochloropsis gaditana, and that is what these figures are based on. If your product uses a different species, these numbers do not apply.

Marine Phytoplankton Nutrition Facts at a Glance

Marine Phytoplankton Calories, Macronutrients, and Serving Size

At a typical supplement dose of 2 to 5 grams, the calorie contribution from marine phytoplankton is negligible. You are looking at roughly 8 to 20 calories per serving, most of which come from protein and fat.

Protein at Supplement Doses vs Food Doses

Nannochloropsis is roughly 30 to 45% protein by dry weight, with a complete amino acid profile (Zanella and Vianello, 2020). That sounds impressive until you do the arithmetic. At 2 to 5 grams per day, you are consuming roughly 0.6 to 2.3 grams of protein. A tablespoon of porridge oats delivers more.

Phytoplankton is a useful broad-spectrum amino acid contribution alongside its EPA and pigments. We include the protein content on our labels because it is present, not because we consider it a reason to buy the product.

Fat Content and Omega-3 Fatty Acids

Total fat in Nannochloropsis typically ranges from 15 to 30% of dry weight, depending on growing conditions. The proportion that matters nutritionally is the EPA fraction within that total fat. The next section covers this in detail.

Vitamins in Marine Phytoplankton

Nannochloropsis contains B-group vitamins, including traces of B12 on some nutritional panels. The concentrations vary with cultivation conditions and are generally modest at supplement doses.

The B12 Question

B12 deserves its own note because it is frequently cited as a benefit of microalgae supplements for vegans. The issue is that standard assays detect both true cobalamin (which your body uses) and pseudocobalamin (which it largely cannot). Not every manufacturer distinguishes between the two forms on the label.

If you are vegan and relying on phytoplankton for B12, we would not recommend it as your sole source. A dedicated B12 supplement is cheaper and more reliable. Your GP can check your B12 status with a blood test.

Minerals in Marine Phytoplankton

Iron, magnesium, zinc, and other trace minerals are present in Nannochloropsis biomass. The concentrations shift with growing conditions: a product cultivated in nutrient-rich media will have a different mineral profile from the same species grown in a leaner medium.

At supplement doses, the mineral contribution is real but modest. It adds to your overall intake rather than covering a significant proportion of your daily requirements on its own. If you have a specific mineral deficiency, a targeted supplement will be more effective than relying on phytoplankton for that purpose.

Iodine is worth addressing specifically because seaweed supplements can deliver problematically high amounts. The average iodine content of microalgae in a UK study of commercially available products was 17.6 µg per gram of dry biomass. At a 3 g daily dose, that is roughly 53 µg, well under the UK RNI of 150 µg per day.

Our phytoplankton is grown in filtered water rather than seawater, which likely reduces iodine content further. If iodine is something you need to manage, phytoplankton is not the category that should concern you.

Does Marine Phytoplankton Contain Omega-3 Fatty Acids?

Yes, and this is the primary nutritional reason Nannochloropsis appears in supplements. Published lipid analyses consistently show EPA constituting 20 to 30% of total fatty acids in this species (Ma et al., 2016; Zanella and Vianello, 2020). That is a remarkably high proportion for any photosynthetic organism.

EPA Content: Percentage vs Milligrams Per Serving

The percentage figure tells you how EPA-rich the organism is. The milligram figure tells you how much EPA you are actually getting per dose. A product could show a high EPA proportion but contain a low total fat content per scoop, leaving you with fewer milligrams than you expected.

The number to check on the nutritional information panel is EPA in milligrams per serving. We state this on our own labels because it is the figure you can match against the EFSA-authorised heart health claim: 250 mg combined EPA and DHA daily (Commission Regulation EU 432/2012).

DHA: The Omega-3 That Phytoplankton Does Not Provide

Nannochloropsis produces EPA, not DHA. These are different fatty acids with different roles. If your goal is both from plant sources, you need a separate algae-derived DHA supplement (typically from Schizochytrium) to cover the other half.

Antioxidants and Other Compounds in Marine Phytoplankton

Open a tub of whole-cell phytoplankton powder and what you notice first is the colour: a deep, vivid green that stains the spoon. That colour comes from photosynthetic and photoprotective pigments the organism produces to survive.

Nannochloropsis produces chlorophyll a, violaxanthin, vaucheriaxanthin, and beta-carotene (Di Lena et al., 2019). Violaxanthin is the standout. Published analyses report concentrations of 1.2 to 3.4 mg per gram of dry cell weight in N. gaditana (Neto et al., 2018; Lena et al., 2019).

For context, egg yolk contains roughly 0.01 mg/g of zeaxanthin, and violaxanthin barely registers in it at all. That is a concentration difference measured in orders of magnitude, not percentages.

These pigments have documented antioxidant activity in laboratory systems. Whether dietary violaxanthin produces measurable health benefits at supplement doses has not been established by human clinical trials. No EFSA-authorised health claim exists for any of these phytoplankton pigments.

A 2024 study on phosphorus-limited N. gaditana cultures showed violaxanthin production could increase more than threefold under specific growing conditions. The pigment content of your supplement depends on how the algae were cultivated, not just which species was used.

Marine Phytoplankton vs Spirulina and Chlorella Nutrition Facts

These three organisms sit together on the supplement shelf but their nutritional profiles are genuinely different. Spirulina is 55 to 70% protein with unique phycocyanin but no meaningful omega-3. Chlorella has the highest chlorophyll density and 50 to 60% protein, with ALA but no EPA. Nannochloropsis leads on EPA but has lower protein per gram than either.

The practical question is which gap you are filling. For omega-3: phytoplankton. For protein density: spirulina. For chlorophyll and iron: chlorella. Our full comparison covers the trade-offs in detail.

Is Marine Phytoplankton a Complete Source of Nutrition?

No. At supplement doses of 2 to 5 grams, marine phytoplankton contributes meaningfully to your EPA intake and provides a broad-spectrum matrix of pigments, amino acids, and trace minerals. It does not provide clinically significant amounts of protein, does not deliver DHA, and cannot replace a balanced diet or a targeted supplement for specific deficiencies like B12 or vitamin D.

Products that describe phytoplankton as "complete nutrition in one scoop" are overstating what any single organism can deliver at a 2 to 5 gram dose. The genuine case for phytoplankton is specific: plant-source EPA omega-3, with a supporting cast of pigments and micronutrients. That is a strong enough proposition without the exaggeration.

What Marine Phytoplankton Nutrition Facts Do and Do Not Tell You

A nutritional information panel tells you what is in a representative batch. It does not tell you how the product was grown, whether the specific batch you are holding was tested for heavy metals, or whether nutrient levels are consistent from one batch to the next.

Three things to check beyond the panel:

Species name. The panel should identify Nannochloropsis gaditana or another specific species. "Marine phytoplankton" without a species is a category label, not an ingredient.

EPA in milligrams per serving. Not total omega-3, not percentage of fatty acids. Milligrams are what you can compare against the 250 mg EFSA threshold.

Batch-specific testing. A certificate of analysis from an independent laboratory confirms the numbers on the panel match the product in the tub.

FAQs About Marine Phytoplankton Nutrition Facts

How much EPA do you get per serving of marine phytoplankton?

Check the back of the tub for milligrams per serving, not percentages. The EFSA threshold for the heart claim is 250 mg combined EPA and DHA daily. Work out whether one serving gets you there or whether you need to combine it with another source.

Is marine phytoplankton a good source of protein?

By dry weight, yes. By what lands in your spoon, no. A 3 g scoop delivers roughly 1 g of actual amino acids. Useful as a broad-spectrum top-up, but if you want a serious plant-based dose, look at chlorella or a dedicated powder instead.

Can you rely on marine phytoplankton for B12?

No. Some of the B12 detected may be pseudocobalamin, which your body handles differently. A standalone B12 tablet is cheaper and certain. Ask your GP for a blood test if you are unsure about your levels.

What nutrients does whole-cell phytoplankton have that algae oil does not?

Whole-cell powder retains chlorophyll, carotenoid pigments (including violaxanthin), amino acids, and minerals alongside the EPA. Extracted algae oils isolate the fatty acids and discard everything else. If the broader nutrient profile matters to you, the format choice is not neutral.

How do you know the nutrition label is accurate?

A printed nutritional panel reflects a representative batch. It does not guarantee every subsequent batch matches exactly. Batch-specific testing with a certificate of analysis from an independent laboratory is the only way to verify. If the manufacturer cannot produce one, the label is a best estimate rather than a verified result.

Is marine phytoplankton more nutritious than spirulina or chlorella?

That question has no single answer because it depends on what you need. For long-chain omega-3: yes. For sheer protein per gram: spirulina wins. For iron and chlorophyll density: chlorella. There is no universal ranking. Pick the one that fills the gap in your diet, not the one with the boldest label.

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. We have a direct commercial interest in this ingredient. All nutritional figures are drawn from published peer-reviewed literature cited above. The EFSA-authorised health claim for EPA and DHA is cited under Regulation EU 432/2012 with its intake condition stated. Comparisons with spirulina and chlorella reflect established compositional differences documented in published reviews. The Phytality Perspective box reflects our product specifications.

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