Is spirulina dangerous? The data is more reassuring than the rumors, though not without concerns. In a Canadian analysis of 18 cyanobacteria-based supplements, 3 of the 14 spirulina products contained microcystins, liver toxins produced by other cyanobacteria, at levels of 0.25 to 0.84 µg per gram, while products based on another cyanobacterium contained nearly ten times more.
This guide compiles studies identified via PubMed: tolerability in trials, product contaminations, clinical cases, contraindications, interactions and common misconceptions, with each risk classified according to its level of evidence.
Tolerability : in 23 studies conducted in 1,035 overweight adults, taking 0.02 to 10 g daily for 2 to 24 weeks, no serious adverse effects were reported, and a placebo-controlled trial in 1,126 patients showed no difference in secondary endpoints, including adverse effects. Vomiting appears only at very high doses, 32 g in a single dose. The documented risks are elsewhere: microcystins in some products, metals at varying levels, and rare individual reactions in isolated cases: sometimes severe allergies, liver or muscle damage, autoimmune flare-ups.
Contraindications and precautions : phenylketonuria requires avoiding spirulina, which is very high in protein. Medical advice is necessary in case of autoimmune disease, immunosuppressant, anticoagulant or antidiabetic medication, gout, pregnancy, breastfeeding, and in children. Its vitamin B12 is primarily an inactive form. Choosing spirulina alone avoids the most contaminated products in published analyses, without ruling out microcystins or metals, which vary from batch to batch.
- Spirulina: a cyanobacterium, not an algae
- What trials show: overall good tolerability
- Microcystins: a risk from other cyanobacteria
- Metals, aluminum and bacteria
- Liver and muscles: published clinical cases
- Allergy: rare, but sometimes severe
- Autoimmune diseases and immunosuppressants
- Phenylketonuria, gout, diabetes, anticoagulants
- Pregnancy, breastfeeding, children
- Common misconceptions: vitamin B12 and blue-green spirulina
- The risk table
- Choosing and taking your spirulina while limiting risks
- Frequently asked questions
Spirulina: a cyanobacterium, not an algae
Spirulina is the dried biomass of cyanobacteria of the genus Arthrospira, mainly A. platensis and A. maxima, separated from the genus Spirulina in 1989: bacteria capable of photosynthesis, not algae in the strict sense. They thrive in alkaline waters, rich in carbonates, and are cultivated around a pH of 9 to 10, conditions that do not suit many other cyanobacteria.
When dried, it contains 60 to 70% protein, pigments such as phycocyanin, vitamins and minerals. Our tablets of Organic Spirulina are made from Spirulina platensis from organic farming. Its studied effects are featured in our article on the benefits of spirulina ; this one addresses its safety.
The question arises for three reasons: cultivation in open pools, where other cyanobacteria and bacteria can establish themselves; metals in variable quantities; an effect on the immune system.
Established : repeatedly observed in trials or product analyses. Rare : documented in humans through isolated cases, with no known frequency and often without proof of causality. Theoretical : plausible based on mechanism, animal or laboratory data, without established human cases. Common misconception : widespread claim that the data contradicts.
What the trials show: overall good tolerance
In 2011, an expert committee reviewed the trials, animal studies and 31 reports of adverse effects, then assigned to Spirulina maxima and Spirulina platensis its safety class A, revisable according to new data. Since then, the most recent meta-analysis in overweight adults brings together 23 studies and 1,035 participants, including people with diabetes, hypertension or living with HIV, with 0.02 to 10 g per day, including extracts, for 2 to 24 weeks: the authors note that no serious adverse effects are reported in the included studies, without having analyzed tolerance as a criterion.
In 1,126 adults with Covid-19 and at risk of severe disease, 569 took 1 g of spirulina twice daily for 14 days and 557 took placebo. Adverse effects were among the secondary criteria, with no difference from placebo. Spirulina also did not reduce hospitalizations: 11.2% versus 8.1% under placebo, a difference that the analysis does not distinguish from chance (odds ratio 1.24; credibility interval 0.84 to 1.86).
Reis G, Augusto Dos Santos Moreira Silva E, Carla Medeiros Silva D, et al. Am J Clin Nutr 2024;120(3):602-609. DOI: 10.1016/j.ajcnut.2024.06.016
The dose in this trial, 2 g per day, corresponds to four tablets of our Organic Spirulina. Other trials: 2 g per day for 3 months in 60 type 2 diabetics on metformin, with no adverse effects; 15.2 g per day for 6 days in 189 patients hospitalized for Covid-19, in an open trial, with no side effects attributed to the supplement; 2 g per day well tolerated in 179 Cambodian preschool-age children, in a crossover trial versus placebo.
The limit appears with very high doses. In a crossover trial in young adults, a beverage of 32 g of spirulina powder in a single dose, or 20 g of protein, was followed by two vomiting episodes, compared to six after chlorella beverages; the authors note difficulties with taste and tolerance at these quantities, far exceeding the 2 to 5 g of common use.
Good tolerance in adults, at 1 to 10 g per day, is established, with two limitations: trials rarely longer than six months, and nothing on contaminations, the subject of the following sections.
Microcystins: a risk from other cyanobacteria
Microcystins are liver toxins produced by certain cyanobacteria, including Microcystis. Molecular analyses have not found the complete pathway for producing these toxins in spirulina strains, despite two controversial studies on Kenyan strains: their presence in a product is very likely explained by other cyanobacteria that developed in the cultivation basin.
Compare with Aphanizomenon flos-aquae, a cyanobacterium harvested from a natural lake. In Italy, among 17 brands, pure spirulina products were free from contamination, while those based on Aphanizomenon contained up to 5.2 µg of microcystins per gram, with variations of up to 50-fold between batches of the same brand. In Germany, among 13 products, only those containing Aphanizomenon tested positive.
| Study | Products analyzed | Result |
|---|---|---|
| Vichi, 2012, Italy | 17 brands of cyanobacteria | Spirulina alone: no contamination; Aphanizomenon: up to 5.2 µg per gram |
| Heussner, 2012, Germany | 13 products, spirulina, Aphanizomenon, chlorella | Only products with Aphanizomenon positive, 1 µg per gram maximum |
| Roy-Lachapelle, 2017, Canada | 18 products, including 14 spirulina | 3 spirulinas out of 14: 0.25 to 0.84 µg per gram; Aphanizomenon: 0.8 to 8.2 |
| Pinchart, 2023, France | 623 samples from 109 farms | Average 0.21 µg per gram, maximum 1.31 |
| Rhoades, 2023, Greece | 2 supplements, 3 spirulina-enriched foods | Microcystins in all 5 products, 0.143 to 0.321 µg per gram |
Spirulina is not always free from contamination either. In the Canadian analysis, 4 out of 18 products exceeded the tolerable daily intake adopted by the authors, 0.04 µg per kilogram of body weight, or 2.4 µg per day at 60 kg, up to 683% above; the text does not specify how many were spirulina. Anatoxin-a, a neurotoxin, was measured in two supplements, and BMAA, capable of causing neurodegeneration in animals, in two samples, at 0.04 and 0.55 µg per gram; the available text does not clarify whether these were spirulina or Aphanizomenon.
Between 2013 and 2021, 623 samples of dried spirulina from 109 French farms were analyzed: 42% were below the quantification threshold, the average reached 0.21 µg of microcystins per gram and the maximum 1.31 µg. For 3 g per day, the estimated intake was 10 ng per kilogram in a 60 kg adult, more than four times below the tolerable daily intake of 40 ng per kilogram, and the authors call for continued monitoring. The data were provided by producers, whose federation co-signed the study.
Pinchart PE, Leruste A, Pasqualini V, et al. Toxins 2023;15(6):354. DOI: 10.3390/toxins15060354
In Greece, the two spirulina supplements tested were the most contaminated of the five products: at manufacturers' doses, 900 ng per day for powder and 1,000 ng for tablets, below the tolerable dose for a 60 kg adult of 2,400 ng, but above that for a 20 kg child of 800 ng, and for an infant of 200 ng. The three spirulina-enriched foods, consumed at the indicated portions, even exceeded the tolerable dose for adults (4,700 to 5,700 ng). The authors consider five products insufficient to draw conclusions.
Contamination is established for a portion of spirulina products, at levels most often low and lower than those in Aphanizomenon-based products. At the usual doses of supplements, the estimated intake generally remains below the tolerable dose for adults, but not for the enriched foods in the Greek analysis; the margin is narrower in children. The risk depends mainly on the product and batch.
Metals, aluminum and bacteria
In 25 spirulina products sold worldwide, one analysis measured 0.002 to 0.028 mg of mercury per kilogram, well below reference intakes. In 24 samples, another team measured in the powder 88.1 µg of lead, 37.2 µg of cadmium and 28.1 mg of aluminum per kilogram: for a 68.5 kg adult following the dosage, the intake represented 2.04% of the tolerable weekly intake for aluminum, 1.05% for cadmium and 1.05% of the reference dose of lead for kidney, with no risk according to the authors.
Other analyses are less favorable. In South Korea, among 535 health foods, spirulina products had the highest average lead content, 0.940 mg per kilogram. A probabilistic assessment of 29 plant preparations estimated that those based on spirulina could represent 11 to 176% of the tolerable weekly intake of aluminum, even in adults.
Regarding bacteria, a genetic analysis of 31 brands sold in Greece found spirulina dominant everywhere, but also, in certain products, other cyanobacteria including some potentially toxic species, and 9 to 157 types of bacteria per product, some closely related to genera known to cause health problems, such as Vibrio or Clostridium. This method detects DNA, not live bacteria. In the 2023 Greek analysis, live bacteria remained relatively scarce, at most 3.2 log, or approximately 1,600 per gram, but some were potentially pathogenic, which concerns the authors for immunocompromised individuals.
The presence of metals and bacteria is established, most often at low levels; these studies measure products, not effects in consumers. Immunocompromised individuals: medical advice before taking it.
Liver and muscles: published clinical cases
A clinical case provides neither the frequency of an effect nor proof of its cause; it mainly indicates what signs to monitor.
The liver. In 2002, a letter described liver damage associated with spirulina in a middle-aged man. In Slovenia, a series reported five episodes of liver damage in four patients who took fat burners containing, depending on the product, green tea extract, garcinia, green coffee, or spirulina, without specifying which patient took which product: spirulina was therefore not specifically incriminated.
Between 2010 and 2015, four patients were hospitalized in Ljubljana for five episodes of liver damage following commercial fat burners. One required a transplant. Biopsy was performed on all patients, viral, autoimmune, and metabolic causes were ruled out, and the authors identified these products as the most probable cause.
Gavrić A, Ribnikar M, Šmid L, et al. Nutrition 2018;47:110-114. DOI: 10.1016/j.nut.2017.10.002
In rats, a 2026 study administered 1,000 or 1,500 mg of spirulina per kilogram of body weight for 28 days: biochemical changes and lesions of the liver and kidneys appeared, more pronounced at higher doses. These doses far exceed typical human use: a theoretical result for humans.
The muscles. In 2008, a Greek team reported the first case of acute rhabdomyolysis, a sudden destruction of muscle fibers, in an adult man taking spirulina (Arthrospira platensis); the authors attribute it to spirulina, but this is an isolated case.
Liver and muscle damage are rare, without demonstrated causality. They justify stopping and consulting if jaundice, dark urine, unusual fatigue, or unexplained muscle pain occur.
Allergy: rare, but sometimes severe
A 2024 review searched for published cases of spirulina allergy in two major databases. It found only five, in four European publications, and concludes that this allergy is rarely reported or diagnosed. However, four of these reactions met anaphylaxis criteria, and three patients required hospitalization.
A 17-year-old adolescent experienced anaphylaxis the first time he swallowed a spirulina tablet. Skin tests were positive for the diluted tablet and spirulina alone, negative for other ingredients (silicon dioxide, inulin, magnesium stearate): spirulina was indeed the culprit.
Le TM, Knulst AC, Röckmann H. Food Chem Toxicol 2014;74:309-310. DOI: 10.1016/j.fct.2014.10.024
According to the review, this young man was atopic (eczema, asthma, allergic rhinitis) and received epinephrine. The first case, published in 2010, involved a 14-year-old boy: hives, lip swelling, and asthma attack six hours after five tablets. The authors identified phycocyanin, the blue pigment of spirulina, as the allergen responsible. Two British patients allergic to birch pollen reacted to spirulina powder in a smoothie, and a 48-year-old Swiss woman experienced a delayed reaction, 3 and 7 hours after three tablets, with tongue swelling.
Spirulina allergy is rare but can be severe from the first dose, and a small amount does not protect against a severe reaction: if there is a history of anaphylaxis or multiple allergies, first consult an allergist. Any spirulina allergy also excludes blue spirulina, concentrated in phycocyanin.
Autoimmune diseases and immunosuppressants
In volunteers, oral intake of a hot water spirulina extract increased NK cell activity, innate immunity lymphocytes, measured by their production of interferon gamma and their ability to destroy cells, in more than half of participants. This effect raises concerns in cases of autoimmune disease.
An American dermatology team described three patients whose autoimmune disease began or worsened after immunostimulant supplements: echinacea and Spirulina platensis were implicated in flare-ups of pemphigus vulgaris in two of them, and a supplement combining spirulina and Aphanizomenon had preceded the onset, then a severe flare-up, of dermatomyositis in a patient carrying a genetic variant promoting TNF alpha production.
In Japan, a 49-year-old woman developed a rash a few days after supplements containing spirulina, which continued to spread despite stopping supplements two months later, then muscle weakness five months later, with creatine kinase at 1,268 IU and inflammatory myopathy, improved by corticosteroids and cyclophosphamide. In 2024, dermatomyositis with anti-Mi-2 antibodies was described following spirulina intake.
These rare cases do not prove that spirulina triggers autoimmune diseases: the authors suggest an effect in predisposed individuals. However, we found no trials designed to evaluate this risk in lupus, arthritis, pemphigus, or dermatomyositis, nor in people on immunosuppressants, for example after transplantation, whose effect spirulina could theoretically counteract. No spirulina, therefore, without physician approval.
Phenylketonuria, gout, diabetes, anticoagulants
Phenylketonuria: contraindication. This genetic disease prevents the breakdown of phenylalanine, present in all proteins, and its treatment is based on restricting natural proteins: the 33 European centers that responded to a recent survey all prescribed a low-phenylalanine diet. With 60 to 70% protein, 3 to 5 g of spirulina provides approximately 2 to 3.5 g of protein, therefore phenylalanine.
Gout: caution. Cyanobacteria are rich in nucleic acids, whose purines become uric acid. According to a British team, spirulina contains approximately 1,076 mg of purines per 100 g, much more than cereals or eggs; in their trial, 32 g in a single dose, with 75 g of carbohydrates, raised blood uric acid to an average of 397 µmol/L in men and 332 µmol/L in women, near the thresholds of 420 and 360 µmol/L. At usual doses, purine intake is six to sixteen times lower, but has not been studied in people with gout.
Diabetes: monitor blood glucose. A meta-analysis of 8 studies in type 2 diabetics found a decrease in fasting blood glucose of 17.88 mg/dL, and in the trial conducted with metformin, glycated hemoglobin decreased by 1.43 points in 3 months. These effects can be added to treatment, to be adjusted if needed (see our article on elevated blood glucose). The decrease in diastolic blood pressure, approximately 2.6 mmHg according to the meta-analysis of 23 studies, is modest and of very low certainty (see our plants for blood pressure).
Anticoagulants: theoretical. In the laboratory, a spirulina polysaccharide, calcium spirulan, increased the antithrombin activity of a natural coagulation inhibitor by more than 10,000-fold. In humans, a randomized 2-week trial with a phycocyanin-rich extract did not modify platelet activation or coagulation times. No interactions have been described in the studies found; still, mention spirulina to your doctor.
Biological analyses. A 2015 letter described highly discordant values of the CA 19-9 marker in an apparently healthy patient taking spirulina. Mentioning spirulina before a blood test can avoid unnecessary examinations.
| Situation | What the data says | Practical course of action |
|---|---|---|
| Phenylketonuria | 60 to 70% protein, therefore phenylalanine | Contraindication, unless advised by the medical team |
| Autoimmune disease, immunosuppressants | Immunostimulant effect of an extract, isolated cases of flare-ups | Not without medical approval |
| Gout | Rich in purines, increase in uric acid at high doses | Medical advice |
| Treated diabetes | Fasting blood glucose lowered in a meta-analysis; glycated hemoglobin lowered in a trial | Monitor blood glucose, inform the doctor |
| Anticoagulants | Effect in the laboratory, no effect in a human trial | Inform the doctor |
| Known allergy | Five published cases, four of which anaphylaxis | Avoid spirulina and blue spirulina |
Pregnancy, breastfeeding, children
Our search in PubMed identified no controlled trials in pregnant or breastfeeding women; available studies are in animals. A 2012 letter reported severe neonatal hypercalcemia, excess calcium in the blood, in a baby whose mother had taken a supplement containing spirulina during pregnancy. It is an isolated case, but the absence of data is not proof of safety. The authors of the Canadian analysis also remind us that a rat study showed the passage of BMAA into milk. During pregnancy and breastfeeding, no spirulina without medical advice.
In children, spirulina has been used against malnutrition, under supervision: in 179 Cambodian children, 2 g per day was well tolerated, and the number of anemic children decreased by 11 with spirulina versus 6 with placebo. But the tolerable dose of microcystins is proportional to body weight: in the Greek analysis, the supplements tested exceeded that for a 20 kg child, and only one-third of the products analyzed by the Canadian team carried a warning for children. Outside medical supervision, it is better not to give it to children.
Common misconceptions: vitamin B12 and blue spirulina
Common misconception: spirulina provides vitamin B12. The high levels sometimes claimed may come from microbiological assay, which does not distinguish true B12 from its analogs. In spirulina tablets, this assay gave values 6 to 9 times higher than a method based on intrinsic factor, the protein that allows B12 absorption.
In spirulina tablets, the two forms of B12 capable of binding to intrinsic factor were purified: the main form, 83%, was pseudovitamin B12, and only 17% was true vitamin B12.
Watanabe F, Katsura H, Takenaka S, et al. J Agric Food Chem 1999;47(11):4736-4741. DOI : 10.1021/jf990541b
In young children deficient in B12, algae, nori and spirulina, and fermented plant-based foods increased the B12 measured in blood, but the volume of red blood cells, already abnormal, further deteriorated, whereas it improved with fish or a B12 supplement. Relying on spirulina for B12 therefore does not protect against deficiency; our article on vitamin B12 details reliable sources.
Blue spirulina is not another species, but an extract of spirulina concentrated in phycocyanin, presented in our article on blue spirulina. In a randomized double-blind trial, 24 adults received for 2 weeks either 2.3 g per day of an aqueous spirulina extract, approximately 1 g of phycocyanin, or a placebo: the extract modified neither platelets nor coagulation times; the trial was short and small, and its authors were affiliated with a private laboratory and a commercial company. Our Organic Blue Spirulina, concentrated at more than 30% phycocyanin, provides more than 0.9 g per 3 g daily, one level teaspoon, a magnitude of order close to the trial, with a different extract; it is not cooked. A person allergic to spirulina should also avoid it. See also our article on phycocyanin.
The risk table
Frequency is known only for what was measured in trials or product series. For clinical cases, frequency is unknown, due to lack of epidemiological studies; published cases remain few.
| Risk | Frequency and level of evidence | Who is concerned |
|---|---|---|
| Serious adverse effect at usual doses | None reported in 23 studies, no difference from placebo in a trial of 1,126 patients: established | Adults, 1 to 10 g per day |
| Vomiting | Observed at 32 g in a single intake: established at high dose | Massive intakes |
| Microcystins | In some products, at low levels: established | Especially children and heavy consumers |
| Metals, aluminum | Traces measured, estimated intakes low or high depending on studies: established, variable | Depending on the product and batch |
| Bacteria | Bacterial DNA frequent, living bacteria scarce: established, impact unknown | Immunocompromised people |
| Liver damage, rhabdomyolysis | Isolated cases, causality not established: rare | Any consumer |
| Allergy, anaphylaxis | Five published cases, including four anaphylaxis: rare, potentially serious | Allergic predisposition |
| Autoimmune flare-up | Isolated cases, immunostimulant effect of an extract: rare | Autoimmune disease, genetic predisposition |
| Reduced effectiveness of immunosuppressants | Plausible, never studied: theoretical | Transplant recipients, treated autoimmune diseases |
| Phenylalanine intake | Certain, from proteins: established | Phenylketonuria |
| Increased uric acid levels | Measured at 32 g, not studied at usual doses: theoretical at common doses | Gout |
| Bleeding on anticoagulants | Laboratory effect, absent in a human trial: theoretical | People on anticoagulants |
| Source of vitamin B12 | B12 mostly inactive: common misconception | Vegetarians, vegans |
Choosing and taking spirulina while minimizing risks
Selection rules are based on the cited analyses; usage guidelines are practical advice, not study results.
Our two forms are spirulina alone, sourced from organic farming; as with any spirulina, this does not guarantee the absence of contaminants. Our organic spirulina tablets provide 2 g per 4 tablets, with a large glass of water; for the powder, see how to consume spirulina powder. In both cases, do not exceed the recommended daily dose.
Call 15 or 112 in case of swelling of the lips, tongue or face, breathing difficulty, dizziness or widespread hives. Stop and consult quickly in case of jaundice, dark urine, unusual fatigue, muscle pain or weakness, skin rash or flare-up of an autoimmune disease. Stop in case of persistent digestive problems.
100% spirulina tablets (Spirulina platensis), sourced from organic farming. Four tablets daily provide 2 g of spirulina, to be swallowed with a large glass of water, all at once or in several doses spread throughout the day.
View Organic SpirulinaIts studied effects: our article on the benefits of spirulina.
Frequently Asked Questions
Is spirulina dangerous?
Not at the doses studied in healthy adults: in 23 studies involving 1,035 overweight adults, no serious adverse effects were reported. Documented risks come mainly from contamination, which varies by product, and rare individual reactions such as allergies.
What are the side effects of spirulina?
At usual doses, trials do not report serious adverse effects. At very high doses, 32 g in a single dose, vomiting has been observed. Isolated cases describe allergies sometimes severe, liver or muscle damage and autoimmune flare-ups, without causality always established.
What are the contraindications of spirulina?
Phenylketonuria, because spirulina contains 60 to 70% protein, including phenylalanine, and known allergy to spirulina. Medical advice is necessary in case of autoimmune disease, immunosuppressant, anticoagulant or antidiabetic treatment, gout, pregnancy, breastfeeding and in children.
Is spirulina bad for the liver?
A few cases of liver damage have been published, without proof that spirulina is the cause, and trials do not report serious adverse effects. Microcystins, liver toxins produced by other cyanobacteria, can contaminate certain products, hence the value of spirulina alone, without this excluding all contamination.
Can spirulina cause stomach pain?
Trials at usual doses do not report serious adverse effects, but large quantities in a single dose are less well tolerated: 32 g was followed by two episodes of vomiting in a small trial. Digestive problems with hives or swelling should suggest an allergy.
Can you take spirulina while pregnant or breastfeeding?
No controlled trials in pregnant or breastfeeding women were identified in PubMed, and one case of severe neonatal hypercalcemia was reported after the mother took a supplement containing spirulina. During pregnancy and breastfeeding, spirulina should not be taken without medical advice.
Is spirulina not recommended in case of autoimmune disease?
Yes, unless your doctor agrees otherwise. A spirulina extract stimulated certain immune cells in volunteers, and cases of pemphigus onset or flare-ups, dermatomyositis, and inflammatory myopathy were reported after taking it. Studies are lacking to assess its safety in these conditions and when used with immunosuppressants.
Spirulina and anticoagulants: is there a risk?
The risk remains theoretical: a polysaccharide in spirulina enhances a coagulation inhibitor in the laboratory, but an extract rich in phycocyanin did not alter platelets or coagulation times in a 2-week trial. Still, mention spirulina to your doctor.
What daily dose of spirulina is safe?
Studies most often used 1 to 10 g per day, for up to six months, with no serious adverse effects reported. Supplements often indicate 2 to 5 g per day: start with half the dose and do not exceed the stated dose.
Does spirulina contain vitamin B12?
Mostly in an inactive form: in spirulina tablets, 83% of purified B12 capable of binding to intrinsic factor was pseudovitamin B12. In B12-deficient children, algae did not correct red blood cell abnormalities. Spirulina is not a reliable source of B12.
Is blue spirulina dangerous?
In a 2-week trial versus placebo in 24 adults, approximately 1 g of phycocyanin per day did not alter platelets or coagulation. Phycocyanin was, however, identified as the allergen in one case of anaphylaxis: a person allergic to spirulina should also avoid blue spirulina.
How can you tell if spirulina is contaminated?
Only laboratory analysis can determine this. Pure spirulina products are significantly less contaminated with microcystins than those containing Aphanizomenon, and contamination levels vary from batch to batch. Choosing pure spirulina with indicated origin and batch number is a practical guideline, though it does not guarantee the absence of contaminants.
Sources
The studies cited below were identified via PubMed.
- Roy-Lachapelle A, Solliec M, Bouchard MF, Sauvé S. Detection of cyanotoxins in algae-based dietary supplements. Toxins, 2017;9(3):76. DOI
- Fu Z, Zhou S, Gu X. Effects of spirulina alone or combined with exercise on cardiometabolic health in overweight or obese adults: systematic review and meta-analysis. Frontiers in Nutrition, 2025;12:1624982. DOI
- Reis G, Augusto Dos Santos Moreira Silva E, Carla Medeiros Silva D, et al. Effect of spirulina on hospitalization risk in patients with Covid-19: the TOGETHER randomized trial. The American Journal of Clinical Nutrition, 2024;120(3):602-609. DOI
- Williamson E, Monteyne AJ, Van der Heijden I, et al. Ingestion of spirulina, whole or disrupted cell chlorella, and milk proteins leads to different plasma amino acid responses after meals, with comparable glycemic control in humans. Frontiers in Nutrition, 2024;11:1487778. DOI
- Gromek W, Kołdej N, Kurowski M, Majsiak E. Spirulina: antiallergic agent or hidden allergen? Literature review. Foods, 2024;13(7):1052. DOI
- Watanabe F, Katsura H, Takenaka S, et al. Pseudovitamin B12 is the predominant cobamide of a health food algae product, spirulina tablets. Journal of Agricultural and Food Chemistry, 1999;47(11):4736-4741. DOI
- Rhoades J, Fotiadou S, Paschalidou G, et al. Microbiota and cyanotoxin content of spirulina supplements and spirulina-enriched foods sold at retail. Microorganisms, 2023;11(5):1175. DOI
- Pinchart PE, Leruste A, Pasqualini V, Mastroleo F. Microcystins and contaminating cyanobacteria in small-scale French spirulina production. Toxins, 2023;15(6):354. DOI
- Marles RJ, Barrett ML, Barnes J, et al. Safety assessment of spirulina by the United States Pharmacopeia. Critical Reviews in Food Science and Nutrition, 2011;51(7):593-604. DOI
- Karizi SR, Armanmehr F, Azadi HG, et al. Double-blind, placebo-controlled randomized trial evaluating the efficacy, safety, and anti-atherogenic effect of Spirulina platensis supplementation in patients with poorly controlled type 2 diabetes. Phytotherapy Research, 2023;37(4):1435-1448. DOI
- Aghasadeghi MR, Zaheri Birgani MA, Jamalimoghadamsiyahkali S, et al. Effect of high-dose Spirulina platensis supplementation in hospitalized adults with Covid-19: a randomized controlled trial. Frontiers in Immunology, 2024;15:1332425. DOI
- Barennes H, Houdart L, de Courville C, Barennes F. Spirulina as a daily nutritional supplement for young preschool-age Cambodian children in disadvantaged settings: a single-blind, placebo-controlled crossover trial. BMC Pediatrics, 2022;22(1):701. DOI
- Vichi S, Lavorini P, Funari E, et al. Contamination by Microcystis and microcystins of blue-green algae-based supplements on the Italian market and potential risk to the exposed population. Food and Chemical Toxicology, 2012;50(12):4493-4499. DOI
- Heussner AH, Mazija L, Fastner J, Dietrich DR. Toxin content and cytotoxicity of algae-based dietary supplements. Toxicology and Applied Pharmacology, 2012;265(2):263-271. DOI
- Al-Dhabi NA. Analysis of heavy metals in commercial spirulina products intended for human consumption. Saudi Journal of Biological Sciences, 2013;20(4):383-388. DOI
- Rubio C, Dominik-Jakubiec M, Paz S, et al. Dietary exposure to trace elements (B, Ba, Li, Ni, Sr and V) and toxic metals (Al, Cd and Pb) through consumption of commercial preparations of Spirulina platensis. Environmental Science and Pollution Research International, 2021;28(17):22146-22155. DOI
- Kim W, Lee KG. Lead and cadmium in functional health foods and traditional Korean medicines. Food Additives and Contaminants. Part B, Surveillance, 2013;6(2):146-149. DOI
- Varrà MO, Husáková L, Lanza GT, et al. Multi-elemental composition of botanical preparations and probabilistic assessment of dietary intakes of toxic metals and metalloids. Food and Chemical Toxicology, 2024;188:114664. DOI
- Vardaka E, Kormas KA, Katsiapi M, et al. Molecular diversity of bacteria in commercial spirulina dietary supplements. PeerJ, 2016;4:e1610. DOI
- Iwasa M, Yamamoto M, Tanaka Y, et al. Hepatotoxicity associated with spirulina. The American Journal of Gastroenterology, 2002;97(12):3212-3213. DOI
- Gavrić A, Ribnikar M, Šmid L, et al. Acute liver injury induced by fat burners: a case series of four patients. Nutrition, 2018;47:110-114. DOI
- Hameed AL, Abbas MA, Mohammed Halmi FT, et al. Biochemical and histopathological analysis of the effect of spirulina on hepatic and renal function in male rats. Future Science OA, 2026;12(1):2563488. DOI
- Mazokopakis EE, Karefilakis CM, Tsartsalis AN, et al. Acute rhabdomyolysis caused by spirulina (Arthrospira platensis). Phytomedicine, 2008;15(6-7):525-527. DOI
- Le TM, Knulst AC, Röckmann H. Anaphylaxis to spirulina confirmed by skin tests with spirulina tablet ingredients. Food and Chemical Toxicology, 2014;74:309-310. DOI
- Petrus M, Culerrier R, Campistron M, et al. First case of spirulina anaphylaxis: identification of phycocyanin as the responsible allergen. Allergy, 2010;65(7):924-925. DOI
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