5 Precautions and Contraindications when Taking Spirulina

Spirulina is an algae that is becoming increasingly popular in diets.  We'll tell you about the precautions and contraindications that you should consider regarding taking spirulina.
5 Precautions and Contraindications when Taking Spirulina
Florencia Villafañe

Written and verified by the nutritionist Florencia Villafañe.

Last update: 27 May, 2022

Recently, spirulina has gained popularity in the food industry because its health benefits have been recognized. However, like any dietary component, there are certain precautions and contraindications to consider before taking spirulina.

Who should avoid taking it?

Spirulina is an alga that grows easily in desert areas and even more so where the water is alkaline. Due to the number of nutrients it provides, many consider it a superfood. Just the same, this doesn’t mean its intake is always safe.

Spirulina: What nutrients does it provide?

Civilizations like the Aztecs and the Incas consumed this substance since ancient times. However, it wasn’t until some time ago that its important properties for human health were rediscovered. Consequently, today many hold it in high regard, and you can obtain it in powder, capsules, liquid, and tablet form.

Sírulina contains protein in high quantities, essential fatty acids, and antioxidants. What’s more, it also contains minerals such as iron, copper, and zinc, and vitamins A, E, and B complex.

The benefits of spirulina

Consequently, several studies highlight that thanks to its components, spirulina can aid in the prevention of some diseases and the reinforcement of the immune system.

Its most recognized actions are the following:

  • It’s antioxidant and antiviral.
  • It retains heavy metals, so it’s a natural chelator.
  • It regulates blood glucose and cholesterol levels.
Spiruline in powder form.
Experts consider spirulina to be a superfood due to its nutritional properties.

What are the precautions and contraindications of taking spirulina?

Although this dietary supplement is safe for most people, in some specific cases it’s best to avoid it. That’s because it may have some adverse effects. Let’s take a closer look at 5 situations that merit precaution.

1. People with bleeding disorders should be careful about taking spirulina

Spirulina has an anticoagulant effect, which means that it slows down the action of platelets that block wounds in the blood vessels. Therefore, it affects the natural action of stopping bleeding.

In this sense, those who take medications with the same effect, for conditions such as atrial fibrillation or stroke, should avoid spirulina. In patients with bleeding disorders, the appearance of bruises and heavy bleeding may intensify.

2. Pregnant women or nursing children

There are no accurate data on the effects of this supplement during pregnancy. However, experts know that algae may be contaminated with toxins or metals.

Heavy metal poisoning is a serious condition that affects several organs. The brain, kidneys, and red blood cells are susceptible to the accumulation of these toxins, which in the medium term constitute an increased risk of developing other diseases.

The placenta and the unit of communication between fetus and mother are also vulnerable to heavy metal poisoning. Therefore, pregnancy is one of the situations where there are precautions and contraindications regarding taking spirulina.

3. People with autoimmune pathologies shouldn’t be taking spirulina

Taking spirulina strengthens the immune system. However, in some situations – like multiple sclerosis, lupus, rheumatoid arthritis, other similar conditions – spirulina could reinforce this effect and thus aggravate these conditions.

Therefore, it’s best to stay away from its consumption in these cases.

4. Allergies

According to some studies, spirulina may have an allergenic component. Therefore, there’s a possibility that it may produce adverse reactions. While exposure to Spirulina is necessary to detect it, those who already suffer from other food allergies should take extreme precautions.

Read more: The Benefits of Spirulina: A Surprising Food You Probably Didn’t Know About

5. Patients with phenylketonuria should be careful before taking spirulina

Phenylketonuria is a hereditary disease that has a low rate of onset in the general population. In these patients, there’s an alteration in the metabolism of the amino acid called phenylalanine.

For these individuals, consuming products that contain this substance, such as algae, is contraindicated. If they do, their body cannot carry out its particular metabolism if symptoms appear.

Spirulina in powder and capsule forms.
Spirulina is available on the market in both capsule and powder form.

What to consider before taking spirulina

To be clear, spirulina is a food that is used as a supplement and not as a medicine. Its consumption in adequate doses is safe for most people, except those mentioned in the previous section.

However, in some particular cases, side effects may occur. These may include skin rash and itching, thirst, constipation, stomach pain, and dizziness. Although this component is an option for the intake of proteins, essential fatty acids, and other nutrients, that doesn’t mean that it’s not capable of producing adverse reactions.

Contrary to popular belief, just because a product is natural doesn’t mean that it will always be harmless. For this reason, if you suffer from any disease, are breastfeeding, or have allergies to certain foods, you should consult your doctor to see if you can incorporate this alga into your diet.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Chen, Y. Y., Chen, J. C., Tayag, C. M., Li, H. F., Putra, D. F., Kuo, Y. H., … & Chang, Y. H. (2016). Spirulina elicits the activation of innate immunity and increases resistance against Vibrio alginolyticus in shrimp. Fish & shellfish immunology55, 690-698.
  • Deng, R., & Chow, T. J. (2010). Hypolipidemic, antioxidant, and antiinflammatory activities of microalgae Spirulina. Cardiovascular therapeutics28(4), e33-e45.
  • Gutiérrez-Salmeán, G., Fabila-Castillo, L., & Chamorro-Cevallos, G. (2015). Aspectos nutricionales y toxicológicos de Spirulina (arthrospira). Nutricion hospitalaria32(1), 34-40.
  • Deng, R., & Chow, T. J. (2010). Hypolipidemic, antioxidant, and antiinflammatory activities of microalgae Spirulina. Cardiovascular therapeutics28(4), e33-e45.
  • Guardia_Alcántara, María_del_Mar. “Revisión del estado actual de la problemática y de los métodos de análisis para determinación de metales pesados en espirulina.” (2018).
  • Bernstein, J. A., Ghosh, D., Levin, L. S., Zheng, S., Carmichael, W., Lummus, Z., & Bernstein, I. L. (2011, March). Cyanobacteria: an unrecognized ubiquitous sensitizing allergen?. In Allergy & Asthma Proceedings (Vol. 32, No. 2).
  • Ponce López, E. (2013). Superalimento para un mundo en crisis: Spirulina a bajo costo. Idesia (Arica)31(1), 135-139.
  • Jensen, Gitte S., et al. “Clinical safety of a high dose of Phycocyanin-enriched aqueous extract from Arthrospira (Spirulina) platensis: Results from a randomized, double-blind, placebo-controlled study with a focus on anticoagulant activity and platelet activation.” Journal of medicinal food 19.7 (2016): 645-653.
  • Zaragozano, Jesús Fleta, and Jorge Fleta Asín. “Valoración nutricional y económica de la utilización de algas.” Revista española de estudios agrosociales y pesqueros 253 (2019): 37-64.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.