What Is Nannochloropsis?
Nannochloropsis is a genus of marine eustigmatophyte microalgae, with Nannochloropsis gaditana being the species most commonly used in supplement production. It is one of the richest plant sources of EPA (eicosapentaenoic acid), a long-chain omega-3 fatty acid that most plant foods do not provide. If you see "marine phytoplankton" on a supplement label and it specifies the species, Nannochloropsis is what you want to find if EPA is your goal.
We grow Nannochloropsis gaditana in closed photobioreactors for our ULTANA Phytoplankton. We evaluated multiple Nannochloropsis species before settling on gaditana for its EPA consistency across batches and its compatibility with our photobioreactor configuration. We covered the full nutritional profile in our Nannochloropsis deep dive.
Why the Species Name Matters for Your Supplement
Not all marine phytoplankton species are EPA-rich. Nannochloropsis channels a large proportion of its lipid production into EPA. Other species produce different fatty acid profiles entirely.
A supplement labelled "marine phytoplankton" without specifying the species could contain any of thousands of organisms. It might still provide useful micronutrients, but you cannot tell whether it delivers EPA at the levels that matter for the EFSA heart-function claim. If you are standing in a health shop comparing two tubs, the species name is the detail that separates a genuine EPA source from a marketing phrase.
Nannochloropsis at a Glance
- Classification: Marine eustigmatophyte microalga
- Primary supplement species: Nannochloropsis gaditana
- Key nutrient: EPA omega-3 (dominant long-chain fatty acid)
- Additional nutrients: Chlorophyll, violaxanthin, carotenoids, complete amino acids
- DHA content: Minimal (not a DHA source)
- Cultivation: Photosynthetic, grown in filtered water, suited to closed photobioreactors
Beyond EPA, Nannochloropsis contains chlorophyll, carotenoids (notably violaxanthin), complete amino acids, and a range of micronutrients. At a typical dose of 2 to 5 grams stirred into your morning water or smoothie, the protein contribution is modest. But the nutritional breadth per gram is part of what distinguishes whole-cell phytoplankton from concentrated oil extracts. Your GP would not prescribe it for protein. They might, however, note the EPA.
If you want to understand the full compositional picture, our Nannochloropsis deep dive covers each nutrient category with its evidence base and limitations.
What our research found
Violaxanthin is the dominant carotenoid, not beta-carotene. Published pigment analyses put violaxanthin in N. gaditana at roughly 3.4 mg per gram of dry biomass, about three times the concentration of beta-carotene in the same material. You will not find this level of violaxanthin in any common dietary source.
EPA yield varies substantially between Nannochloropsis species. Published lipid analyses show that N. oculata strains can reach over 37 per cent of total fatty acids as EPA under optimised conditions, while N. gaditana and N. oceanica tend to produce lower proportions. Cultivation conditions, particularly light and nitrogen availability, shift these numbers significantly. The species on the label is not the only variable that matters.
Whole-cell format preserves what oil extraction strips out. When you take a concentrated algae oil capsule, you get EPA in isolation. Whole-cell Nannochloropsis powder retains the chlorophyll, carotenoids, and phospholipid membrane structures that an extraction process removes. Whether those co-nutrients meaningfully affect absorption is still being studied, but the compositional difference between whole-cell and extracted formats is substantial.
Sources
- Ma XN et al. Lipid Production from Nannochloropsis. Marine Drugs. 2016;14(4):61. PubMed
- Zanella L et al. Fatty Acid Composition and Cytotoxic Activity of Lipid Extracts from Nannochloropsis gaditana Produced by Green Technologies. Molecules. 2022;27(12):3710. PubMed
- Lubian LM et al. Nannochloropsis (Eustigmatophyceae) as Source of Commercially Valuable Pigments. Journal of Applied Phycology. 2000;12:249–255. DOI
Cara Hayes, MSc Nutrition and Dietetics (University of Sydney), writes all content in the Phytality Knowledge Centre. Read our editorial policy.
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Consult your healthcare provider before starting any supplement.
Methodology and Disclosure
Phytality grows Nannochloropsis gaditana and manufactures supplements from this species. We have a direct commercial interest. Species classification and fatty acid profile descriptions reflect published lipid analyses. No EFSA-authorised health claims are cited in this definition page.
Last reviewed: March 2026
