Does spirulina have side effects (read this first)?

The informative blog, "Does spirulina aid with weight loss?" revealed that spirulina may be considered a genuine superfood, as the blue green salt water algae that it’s made from boasts countless beneficial properties that support optimum health. However, many are afraid to take spirulina, because they’re worried about potential side effects. Yet, is their fear really justified? This blog analyses the side effects associated with spirulina in more detail and allows you to draw your own conclusions. 

Does spirulina have side effects?

What are the benefits of spirulina?

Arguably the most significant spirulina benefit is that it’s extremely rich in mature proteins (between 51 and 71%), which contain every essential amino acid. Spirulina additionally boasts a high B-vitamin (thiamine and riboflavin) and mineral content, including iron, magnesium and manganese. Spirulina also contains small amounts of polyunsaturated fatty acids, chlorophyll and phycocyanin, all of which are known for their health-promoting properties. 

One of the main reasons that health conscious consumers take spirulina is that the chlorophyll content of this bright green superfood supports the natural cleansing of the body (Balder et al., 2006[1]), turns the blood alkaline (Schwalfenberg, 2012[2]) and strengthens immunity (e.g. Gonzalez et al., 1999[3]). Spirulina is known to offer countless other benefits, such as relief from allergies (Cingi et al., 2008[4]), the regulation of blood sugar and cholesterol levels in those with type-2 diabetes (Parikh et al., 2002[5]), the improvement of athletic performance (Kalafati et al., 2010[6]), the reduction of anxiety and depression in menopausal women (Genazzani et al., 2010[7]) and aid in weight loss (Becker et al., 1986[8]).

Spirulina side effects

Spirulina would therefore appear to be the ideal superfood for those wishing to provide all-round support to their general health and mental wellbeing. However, like many, you might be hesitant to try spirulina, because you’ve heard that it can cause unwelcome side effects. 

The good news is that a quality organic spirulina product, such as Superfoodies Organic Spirulina Powder, is safe for most people. It’s important to emphasise the issue of quality though, because inferior spirulina products are sometimes contaminated with traces of heavy metals, harmful bacteria and microcystins, which can cause liver damage, abdominal cramps, nausea and vomiting. So, never buy a spirulina product that has not been tested or proven free from microcystins and other pollutants, but rather shop for a premium certified organic spirulina that you can trust.

Spirulina warnings

Although spirulina is safe for the majority of consumers, there are a number of medical warnings related to its use by specific target groups. Women who are pregnant or breast-feeding for example, are recommended not to take spirulina as the effects of spirulina on (unborn) babies has not yet been fully investigated. In addition, those with an autoimmune disease, such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), and pemphigus vulgaris (a skin complaint) are better avoiding spirulina, as it potentially activates the immune system, thus possibly aggravating their symptoms. Lastly, those suffering from phenylketonuria, gout or kidney stones are advised not to take spirulina as it can exacerbate these particular conditions.

The use of spirulina in combination with medication

As you’ve just read, most people needn’t worry about spirulina side effects and can enjoy the benefits of this powerful superfood safely. Those taking medication, however, must exercise caution. Indeed, spirulina can suppress the effectiveness of certain medications that decrease immunity. Medicines that fall under this category include zathioprine (Imuran), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), muromonab-CD3 (OKT3, Ortho clone OKT3), mycophenolate (CellCept), tacrolimus (FK506, Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone) and corticosteroids (glucocorticoids). If you are taking any type of medication you must therefore consult your GP before using spirulina, even if that medication doesn’t feature in the above list.


[1] Balder, Helena F., et al. "Heme and chlorophyll intake and risk of colorectal cancer in the Netherlands cohort study." Cancer Epidemiology Biomarkers & Prevention 15.4 (2006): 717-725.

[2] Schwalfenberg, Gerry K. "The alkaline diet: is there evidence that an alkaline pH diet benefits health?" Journal of Environmental and Public Health 2012 (2011).

[3] Gonzalez, Ricardo, et al. "Anti-inflammatory activity of phycocyanin extract in acetic acid-induced colitis in rats." Pharmacological research 39.1 (1999): 55-59.

[4] Cingi C, Conk-Dalay M, Cakli H, Bal C. The effects of spirulina on allergic rhinitis. Eur Arch Otorhinolaryngol 2008;265:1219-23.

[5] Parikh, Panam, Uliyar Mani, and Uma Iyer. "Role of Spirulina in the control of glycemia and lipidemia in type 2 diabetes mellitus." Journal of Medicinal Food 4.4 (2001): 193-199.

[6] Kalafati M, Jamurtas AZ, Nikolaidis MG, et al. Ergogenic and antioxidant effects of spirulina supplementation in humans. Med Sci Sports Exerc 2010;42:142-51.

[7] Genazzani AD, Chierchia E, Lanzoni C, et al. [Effects of Klamath Algae extract on psychological disorders and depression in menopausal women: a pilot study]. Minerva Ginecol 2010;62:381-8.

[8] Becker, E. W., et al. "Clinical and biochemical evaluations of the alga Spirulina with regard to its application in the treatment of obesity. A double-blind cross-over study." Nutrition Reports International 33.4 (1986): 565-574.

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