IngredientsPhytoplankton are single-celled or small colonial organisms that perform photosynthesis in oceans, lakes, and rivers. They form the base of aquatic food chains and are responsible for a significant share of the planet's oxygen production. Microalgae are unicellular organisms found in aquatic environments; they play a key role in marine ecosystems, forming the basis of the food web as primary producers. As a dietary supplement category, the term "plankton" almost exclusively refers to marine phytoplankton — microscopic photosynthetic microalgae cultivated and concentrated for human consumption.
The supplement market centers on a small number of well-characterized species. When we talk about phytoplankton as a supplement, we usually mean specific strains of marine microalgae grown in controlled tanks, then harvested, purified, and dried into powders or liquid extracts. Common genera in supplements include Nannochloropsis, Tetraselmis, and other marine microalgae selected for their content of omega-3 fatty acids (especially EPA), carotenoids, chlorophylls, vitamins, and trace minerals.
Some products use a single standardized strain; others blend several species to broaden the nutrient profile. Available commercial preparations include:
High-quality supplements are typically grown in closed systems to limit contamination and are tested for heavy metals and toxins.
Phytoplankton — as a discretely harvested and consumed ingredient — has no documented history of direct traditional use in the ethnobotanical or ethnopharmacological literature. Unlike macroalgae (seaweeds) such as nori or kelp, which have thousands of years of recorded culinary and medicinal history in East Asian and Pacific Islander cultures, marine phytoplankton microalgae were not accessible to pre-modern cultures as isolable food or medicine. Their microscopic size (typically 2–200 μm) precluded collection or preparation by traditional means.
Phytoplankton was, however, consumed indirectly through aquatic food chains. Fish do not synthesize enough long-chain n-3 PUFA; instead, they obtain it from phytoplanktonic microalgae throughout the food chain. Through this process, long-chain PUFAs are bioaccumulated in complex mixtures of DHA and EPA that are predominantly esterified into neutral lipids. Marine-oriented cultures therefore derived phytoplankton-derived nutrients indirectly through seafood consumption.
While phytoplankton itself was not intentionally consumed, its nutritional contributions were central to the diets of coastal peoples worldwide. The connection between long-chain n-3 PUFA intake and cardiovascular health was first proposed in a seminal study conducted in 1971, focusing on the Greenland Inuit population. The Inuit and other Arctic peoples consumed very high levels of EPA and DHA through marine mammals and fish, which ultimately derived these fatty acids from phytoplankton at the base of the food chain.
Among Pacific Coast Indigenous peoples of North America, marine foods formed the core of subsistence and cultural life. In ancient times, the Pacific Ocean provided a wide range of shellfish, crustaceans, seabirds, kelp, fish, and sea mammals, and coastal sites typically contain high densities of shells and bones of marine vertebrates, reflecting this emphasis. Such filter-feeding animals (shellfish, in particular) accumulate phytoplankton directly, making them the most concentrated indirect source of microalgal nutrients in traditional diets.
The deliberate use of phytoplankton as a human dietary supplement is a late 20th- and early 21st-century development, arising from the aquaculture industry's long use of microalgae as feed for marine organisms. Tetraselmis chuii is an EFSA-approved novel food and dietary supplement with increasing use in nutraceutical production worldwide. AlmegaPL®, containing 25% EPA by weight, is the first lipid extract derived from Nannochloropsis made available in 2014 for human consumption. The regulatory classification as a "novel food" in the European Union — meaning it had no significant history of consumption in the EU prior to May 1997 — underscores that the widespread use of phytoplankton as a direct supplement is a recent phenomenon.
The fatty acid profile varies by species. Among the microalgae producing ω3-PUFAs, a distinction can be made between those synthesizing only EPA or DHA, and those synthesizing EPA and DHA, in proportions that vary according to the species and the culture conditions (culture regimen, temperature, salinity, light, pH, and nutrients). The lipids of bacillariophytes (or diatoms) are characterized by high levels of EPA and low or even zero levels of DHA. A recent screening of new strains of microalgae producing bioactive substances highlighted the particular interest of diatoms as EPA-producing organisms; of the nine selected species, Thalassiosira weissflogi had the highest proportion of EPA (21.4% of total fatty acids) and an absence of DHA. DHA is specific to dinoflagellate and haptophyte lipids; dinophytes can produce large amounts of DHA, with up to 40% of total fatty acids in some taxa.
For example, C. cohnii microalgae contain only DHA and practically no other PUFA; N. oculata and P. tricornutum contain mainly EPA, while P. cruentum contains mainly arachidonic acid (ARA). Microalgae, especially Nannochloropsis and Schizochytrium, are prominent sources of EPA and DHA; these lipids are very essential for brain development, cardiovascular health, and anti-inflammatory activity.
Active components including antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and n-3 PUFAs (EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins such as folate are found across edible microalgae. Microalgal bioactive components such as carotenoids, polysaccharides, and phenolic compounds are gaining popularity as very effective and long-lasting natural antioxidants. The most studied areas include the effectiveness, the antioxidant mechanism, and use of bioactive substances in microalgae such as carotene, astaxanthin, and tocopherols, in the fields of food, cosmetics, and medicine.
Tetraselmis chuii is particularly noted for its content of the antioxidant enzyme superoxide dismutase. This microalga contains highly active antioxidant enzymes, particularly superoxide dismutase (SOD), which catalyzes the conversion of superoxide into ordinary molecular oxygen, thereby protecting cells from oxidative damage. Tetraselmis chuii was also found to upregulate glutathione peroxidase and catalase enzymes in human skeletal muscle myoblasts in vitro.
Collectively, results from in vitro and in vivo research support SOD-rich T. chuii as a potential promoter of cellular health. Principally, the ingredient appears to function as an indirect antioxidant by boosting intracellular antioxidant systems. Moreover, it can positively modulate inflammatory status by up-regulating anti-inflammatory and down-regulating pro-inflammatory cytokines and factors.
As a high nutritional source, T. chuii contains all essential amino acids, long-chain polyunsaturated fatty acids (PUFAs), and fat-soluble carotenoids. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future.
Metabolites of marine microalgae include polyunsaturated fatty acids (PUFAs) such as EPA and DHA, pigments like fucoxanthin and astaxanthin, polysaccharides, sterols, peptides, and phenolic compounds, each demonstrating diverse biological properties such as antioxidant and anti-inflammatory effects. Microalgae biomasses are excellent sources of diverse bioactive compounds such as lipids, polysaccharides, carotenoids, vitamins, phenolics, and phycobiliproteins. Besides EPA, Nannochloropsis also produces many other bioactive molecules such as pigments and phytosterols that could provide further cardiovascular benefit.
EPA and DHA help to lower blood pressure, lower triglycerides, and lower the risk of heart disease. The primary microalgal producers often synthesize unmixed long-chain PUFAs that are conjugated to polar lipids, a structural difference from fish-oil-derived EPA that may influence bioavailability and metabolic outcomes.
The SOD-rich T. chuii ingredient appears to function as an indirect antioxidant by boosting intracellular antioxidant systems. Antioxidant SODs participate in the first line of defense against ROS damage within cells by converting reactive superoxide anions to O₂ and hydrogen peroxide (H₂O₂). The induction of catalase and glutathione peroxidase — itself noted in in vitro studies with T. chuii — creates a cascading antioxidant response rather than direct radical scavenging.
Phytoplankton bioactive compounds appear to have antibacterial, antifungal, antiviral, antioxidative, anticancer, neuroprotective, and chemo-preventive activities. These properties confer on microalgae the potential for use in the treatment and/or management of several neurologic and cell dysfunction-related disease conditions, including Alzheimer's disease, AIDS, and COVID-19, though human clinical evidence for most of these applications remains preliminary.
The components of microalgae may be effective against metabolic syndrome at two levels: in the early stages, to work against the development of insulin resistance, and later, when pancreatic beta-cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and n-3 PUFAs.
This is the most substantively researched area for whole phytoplankton supplementation in humans, with multiple prospective randomized controlled trials published in peer-reviewed journals.
Study 1 (Sharp et al., 2021 — PMC8076584): This study investigated the effects of marine phytoplankton supplementation (Oceanix®, Tetraselmis chuii) on maximal isometric strength and immune function in healthy humans following a one-week high-intensity resistance-training program and the proinflammatory cytokine response to exercise in a rat model. In the human trial, 22 healthy male and female participants were randomly divided into marine phytoplankton and placebo groups, and following baseline testing, participants underwent a 14-day supplement loading phase before completing five consecutive days of intense resistance training. Supplementation with the microalgae Tetraselmis chuii improved short-term recovery, reduced functional muscle damage, and better preserved immune function during the fatiguing period. Microalgae supplementation preserved immune function following intensive training, thus initiating a more favorable environment for recovery and adaptation in humans. Mechanistic data in a rat model supported the role of microalgae in modulating the proinflammatory cytokine response and reducing oxidative stress during exercise training.
Study 2 (Sharp et al., 2021 — PMC8566026, overreaching protocol): Scientists isolated a unique source of marine phytoplankton (microalga Tetraselmis chuii), which contains highly active superoxide dismutase (SOD). Previous research found that marine phytoplankton was able to robustly increase intramuscular antioxidant enzymes, lower muscle damage, and sustain anaerobic performance in a short-term (3-day) repeated high-intensity competition-style challenge. It was found that 25 mg/day supplementation improved the recovery of explosive strength after overreaching resistance training and modulated myogenic factors, with no adverse blood changes reported.
Study 3 (Targeted Marine Phytoplankton Supplementation — PMC7259229): The study investigated marine phytoplankton supplementation (Tetraselmis chuii, Oceanix™) that is rich in antioxidant enzymes, essential fatty acids, vitamins, amino acids, and minerals, on explosive strength and immune function during short-term intensive training. Trained male and female subjects were randomly divided into a placebo or Oceanix™ (25 mg per day) condition for 14 days, and subjects were tested at baseline and then placed on an intensified resistance training protocol using multiple sets to volitional failure over 5 days, and retested 24 and 48 hours following.
Evidence strength: While research on human supplementation is emerging, existing controlled studies indicate promising effects, particularly in healthy adults undergoing resistance training. The evidence quality is considered moderate, with a few randomized controlled trials providing valuable insights, though comprehensive systematic reviews or meta-analyses are still lacking. A further limitation is that several of the human trials cited industry funding disclosures; Lonza Consumer Health Inc. supplied treatment (Oceanix™) and placebo conditions, and financially supported at least one study, while one author (Shane Durkee) is employed by Lonza Consumer Health Inc.
RCT — Nannochloropsis EPA extract (Rao et al., 2020 — PMC7353404): The aim of this trial was to assess the effect of Almega®PL on improving the Omega-3 Index, cardio-metabolic parameters, and other biomarkers in generally healthy individuals. The benefits of long-chain omega-3 fatty acids for cardiovascular health are primarily built upon mixtures of DHA and EPA. Highly purified EPA therapy has proven to be particularly effective in the treatment of cardiovascular disease, but less is known about the benefits of EPA-only supplementation for the general healthy population. Participants (n = 120) were given a capsule of 1 g/day of either Almega®PL or placebo for 12 weeks, and differences in the Omega-3 Index, cardiometabolic markers, and other general health indicators were measured at baseline, six, and 12 weeks.
Real-world follow-up study (Ganuza et al., 2024 — PMC10876867): This study demonstrated AlmegaPL®'s capacity to maintain already healthy triglyceride levels by further inducing a 14.9% decrease. Collectively, these findings highlight AlmegaPL® as a natural over-the-counter option for EPA-only polar lipid that appears particularly effective in maintaining blood lipid levels in a generally healthy, normolipidemic population. Consistent with the previous clinical trial, the decrease in remnant cholesterol (RC) was not coupled to an increase in LDL, which seems to be a benefit associated with EPA-only based formulations.
Evidence strength: Evidence for cardiovascular lipid effects of EPA-rich Nannochloropsis extracts is the most clinically developed area, supported by at least one double-blind RCT (n=120, 12-week duration) and a real-world prospective study. These are specific to the AlmegaPL® extract formulation and cannot be automatically extended to uncharacterized whole phytoplankton powders.
A narrative review provided an overview of preclinical and clinical trials assessing the efficacy of a T. chuii-derived ingredient, characterized by a high superoxide dismutase (SOD) activity, to improve various aspects of cellular health. Collectively, results from in vitro and in vivo research support SOD-rich T. chuii as a potential promoter of cellular health. Oxidative stress is a critical factor contributing to the pathogenesis of numerous diseases, including cardiovascular disorders, diabetes, and neurodegenerative conditions. In recent years, marine-derived antioxidants have emerged as promising therapeutic agents due to their unique biological activities and diverse sources.
Evidence strength: Most antioxidant evidence is in vitro or animal-based. Robust human trials specifically measuring clinical antioxidant outcomes from whole phytoplankton are limited. The exercise-recovery RCTs provide indirect evidence of antioxidant protection in vivo, via changes in muscle damage markers and immune function.
Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. More broadly, scientific evidence supports microalgae's antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, and metabolic regulatory activities, contributing to reduced risks of cardiovascular, metabolic, inflammatory, and neurodegenerative disorders.
Evidence strength: Evidence for anti-diabetic and antihypertensive effects of marine phytoplankton in humans is largely indirect, derived from mechanistic studies of constituent compounds (EPA, carotenoids, polysaccharides) or from other microalgal species such as Chlorella. No large-scale RCT focused specifically on marine phytoplankton supplements for metabolic syndrome endpoints was identified in peer-reviewed literature.
The immunological findings from the exercise-recovery RCTs are the primary human evidence in this area. Supplementation with Tetraselmis chuii improved short-term recovery, reduced functional muscle damage, and better preserved immune function during the fatiguing period. Microalgae supplementation can preserve immune function following intensive training, thus initiating a more favorable environment for recovery and adaptation in humans. Bioactive compounds of marine microalgae demonstrate diverse biological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, immunomodulatory, and photoprotective effects, increasingly validated through in vitro and clinical studies.
Evidence strength: Immune function preservation during high-stress exercise has modest human RCT support. Broader immunomodulatory claims in disease contexts remain supported only by preclinical and mechanistic data.
A review covers the health benefits of n-3 PUFA, EPA, and DHA, with particular attention given to various approaches attempted in nutritional interventions using EPA and DHA alone or combined with other nutrients and bioactive compounds towards improved health conditions in people with mild cognitive impairment and Alzheimer's disease. DHA is an important structural element of the brain and retina, which is essential for vision and cognitive function.
Phytoplankton species have also been investigated for neuroprotective phytochemicals. Research into Tetraselmis chuii has explored its content of neuroprotective compounds. These properties confer on microalgae the potential for use in the management of neurologic conditions including Alzheimer's disease.
Evidence strength: Neuroprotective claims are supported by preclinical and mechanistic data. No human clinical trials specifically using whole marine phytoplankton supplements as an intervention for cognitive outcomes were identified. Evidence in this area is preliminary.
A phytoplankton skin extract — a standardized complex of marine microalgae including Microchloropsis gaditana, Dunaliella salina, Isochrysis galbana, Phaeodactylum tricornutum, and Tetraselmis chuii — has been evaluated in vitro and in human clinical studies for dermatological applications. The extract demonstrates antioxidant, anti-inflammatory, regenerative, and moisturizing activities relevant to skin therapy.
Evidence strength: Some in vitro and clinical dermatological studies exist for specific multi-species phytoplankton extracts, but this area remains nascent and the number of published human trials is small.
Dosages are highly form- and species-dependent. The following reflects what has been reported in published studies:
Tetraselmis chuii was authorized in the European Union as a novel food for human consumption in 2014, and as a food supplement in 2017. T. chuii, which does not produce toxins, is harmless to other marine species, and has been approved as a 'novel food' by the American Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). The relevant Scientific Committee agreed with the classification of the product as a food which had no history of consumption in the European Union prior to 1997.
It was demonstrated in at least one human study that the phytoplankton ingredient had no negative impact on any blood safety parameter examined. No serious adverse events have been reported in the published human RCTs conducted to date with either Tetraselmis chuii or Nannochloropsis extracts at the dosages studied.
Microalgae can accumulate heavy metals, pollutants, or marine toxins if grown in contaminated water. This is a recognized concern for any marine-derived supplement. High-quality supplements are typically grown in closed systems to limit contamination and are tested for heavy metals and toxins. Importantly, some phytoplankton species are known producers of biotoxins: some phytoplankton species — microscopic algae — produce marine biotoxins; phytoplankton species can cause paralytic, amnesic, and diarrhetic shellfish poisoning (PSP, ASP, and DSP). These toxin-producing species (e.g., Alexandrium, Dinophysis, Pseudo-nitzschia) are not used in supplements, but they underscore the necessity of strict species identification and quality control.
Contamination with heavy metals such as lead, cadmium, mercury, and metalloids such as arsenic can occur during the production or sourcing of nutraceutical ingredients, leading to potential health risks. Controlled photobioreactor cultivation of supplement-grade phytoplankton substantially mitigates this risk compared to wild-harvested marine biomass.
Because phytoplankton is marine-derived, there is a theoretical risk of cross-reactivity in people with severe fish or shellfish allergies, though direct data are limited. Individuals with known serious seafood allergies should exercise caution, as clinical data on cross-reactivity are absent from the published literature.
Marine phytoplankton sits at the intersection of genuine nutritional science and supplement marketing that has run well ahead of the data. Claims range from solid (omega-3 content) to speculative (liver detoxification) to outright misleading (cure-all superfood). The research on EPA and mood is genuinely interesting, with published studies exploring EPA's role in neurotransmitter modulation and anti-inflammatory pathways. But no EPA-specific health claim for mood, inflammation, or joint health has been authorized by EFSA, and no such application has been publicly submitted or approved since 2020.
Special emphasis in current research is placed on the synergistic benefits of consuming whole biomass compared to isolated compounds, and the technological strategies — such as encapsulation, cell wall disruption, and nutrient optimization — that enhance the bioavailability of microalgal bioactives. Bioavailability of intact, un-processed phytoplankton cells may be limited by the robustness of the cell wall, and processing methodology significantly affects the nutritional potency of finished products.
The overall evidence base for marine phytoplankton as a human dietary supplement is growing but remains in an early-to-moderate stage of development. The strongest clinical evidence exists for: (1) EPA-rich Nannochloropsis extracts and cardiovascular lipid parameters (multiple RCTs including a 120-participant, 12-week double-blind trial); and (2) SOD-rich Tetraselmis chuii for exercise recovery and immune preservation (several small, industry-funded RCTs, n≈22 per trial). Broader claims covering detoxification, cancer prevention, neurodegenerative disease management, hormonal balance, or general "superfood" properties are not supported by human clinical evidence and rest, at best, on in vitro or animal data. No comprehensive systematic reviews or meta-analyses of marine phytoplankton supplements in humans have been published as of the time of this writing. Species standardization, processing methods, dose, and bioavailability vary substantially across commercial products, making generalization across brands difficult.
Health conditions that Plankton may help support.
Body systems that Plankton may help support.
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