Euglena: Nutrients, What Research Shows and Safety

Euglena (Euglena gracilis) is a single-celled organism found in fresh water. It is a microalga that has some animal-like features, and it stores energy as paramylon, a type of beta-glucan, which is a fiber-like sugar chain. [1] [2] [10] It has been produced on an industrial scale as an ingredient for functional foods and cosmetics. [11] Most Euglena products are dried powders or capsules, not a traditional food. This page keeps the whole dried alga apart from isolated paramylon and from hype.

Read this first

• Human evidence is thin. The best trials are 8-to-12-week studies in healthy adults in Japan and Korea, mostly with fewer than 200 people. They measured immune blood markers, cold-like symptoms, mood, sleep or body fat, and results are modest or limited to subgroups. [4] [5] [6] [7] [8]
• Regulators have judged it safe at the uses they reviewed. The European Food Safety Authority (EFSA) concluded that dried whole-cell Euglena gracilis and isolated paramylon are each safe at the proposed uses and use levels, based on lab and animal safety studies. [1] [2] That is a safety opinion, not proof of a health benefit.
• We found no sourced warnings for pregnancy, breastfeeding, medicines or allergy, and also no sourced reassurance. Proper evidence not found in the sources we read. Ask a clinician or pharmacist, especially during pregnancy, with immune-suppressing medicines or with an autoimmune disease.
• Most "benefits" online (cancer, colitis, stroke, obesity, antiviral) come from mice or lab dishes. [9] [12] [13] [14]
• If you get hives, swelling of the face or throat, or trouble breathing after any new food or supplement, call 911 (or your local emergency number).

What is in it (USDA values)

No USDA entry for this food. USDA FoodData Central (SR Legacy) has no Euglena item, so there are no official per-serving nutrient values to show. These are the composition facts we read:

Paramylon is an insoluble beta-1,3-glucan. [6] The immune effects in the trials below were measured in blood. We found no trial that tested isolated paramylon against whole Euglena. The compound evidence is partly from humans (below) and partly from the lab and mice. [4] [5] [6] [12]

What research says

We did not read funding statements in these abstracts, so we cannot say who paid. Several trials tested products from specific Euglena strains or makers, so results may not apply to all products. A 2023 review of Euglena and influenza describes the immune and antiviral work and mixes lab and animal findings; it is not a human trial. [10]

Eaten as food vs taken as paramylon or extract. The whole dried alga, isolated paramylon (≥95% beta-glucan) and water extracts are different products. The EU assessed whole cells and paramylon separately. [1] [2] Mouse cancer and colitis studies often used extracts or purified paramylon, not what is sold as food powder. [9] [13] [14]

How much is a normal serving

There is no official serving for Euglena. USDA lists none and we found no health agency portion. Amounts used in the human trials we read were 700 mg a day of powder [6], 1,000 mg a day [4] and a paramylon-rich powder giving 2.6 g paramylon a day [7], for 8 to 12 weeks. These are trial amounts for information, not a recommendation. EFSA's safety opinion was tied to the proposed uses and use levels in the application, not to a general serving. [1]

Safety, allergy and medicines

• Regulatory safety: EFSA's panel found no adverse effects in a 90-day rat study up to 3,300 mg of dried Euglena per kg body weight a day; margins of exposure to the highest intake estimates ranged from 33 for infants to 192 for adults, which the panel judged sufficient. It concluded the dried whole-cell alga is safe at the proposed uses. [1] It also noted that E. gracilis has "qualified presumption of safety" status for production purposes only. [1]
• Paramylon: no toxicity in studies up to 5,000 mg per kg body weight a day; EFSA concluded it is safe under the proposed uses and use levels. [2]
• Earlier toxicity work: a 2016 study of a dried Euglena product found it was not genotoxic in two tests, and rats fed it for the subchronic period had no treatment-related effects. [3] These are animal and lab results.
• Trials: the 2023 and 2025-2026 trials reported no adverse events, no clinically meaningful lab changes, or judged the product safe. [4] [5] [6] They were short and in healthy adults.
• Children and infants: EFSA's assessment covered the general population including children from 12 months in food supplements. [1] We found no trial in children.
• Pregnancy and breastfeeding, allergy, medicines, autoimmune disease, kidney or thyroid disease, contamination: Proper evidence not found in the sources we read.
• Iodine and B12: we found no source giving iodine or vitamin B12 values for Euglena, so we make no claim about either.

Choosing, storing and food safety

• Look for the species name (Euglena gracilis), the form (whole-cell powder or isolated paramylon), and the amount per serving on the label.
• Check whether a product claims immune or disease benefits. The human evidence is limited to the studies above.
• We found no agency storage or contamination guidance for Euglena; follow the label and see heavy metals and contaminants in foods for general points.

Related pages

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• Chlorella
• Spirulina
• Spirulina vs chlorella
• Blue-green algae supplements, microcystins and quality
• Seaweed medicines and health conditions: vitamin K, potassium, thyroid