Spirulina, often described as a “superfood,” is a blue-green algae belonging to the Oscillatoriaceae family. It has a long history of use as a functional food, dating back to ancient civilizations such as the Aztecs, who valued it for its nutritional properties (J. C. Dillon et. al. 1995).

In more recent times, spirulina gained global attention after being used as a dietary supplement by NASA to support astronauts during space missions (Karkos et. al. 2011),

From a scientific perspective, spirulina is considered a functional food—one that not only provides essential nutrients and energy but may also support various physiological functions and help reduce the risk of certain chronic diseases (Nicoletti, 2012). Rich in protein, vitamins, minerals, and antioxidants, it has been widely studied for its potential health benefits.

In this guide, we explore spirulina’s nutritional profile, five (5) science-backed health benefits, how to incorporate it into your diet, and important precautions to consider before use. Let’s discuss!

What is Spirulina?

Spirulina, a microscopic cyanobacterium, have a long history of being used as food during the Aztec civilization (J. C. Dillon, et. al. 1995).  Spirulina, as a food, is actually the dried biomass of what is called ‘Arthrospira Platensis’, a bacterium that is found in fresh and marine waters (Karkos et. al. 2011). However, while it is usually easy to cultivate, it only flourishes in lakes that are alkaline or have very high PH levels (Karkos et. al. 2011). 

It can also be cultivated in outdoor settings that are set up specifically for that purpose and are controlled.  As such, it is usually found in countries that meet these criteria, such as Japan, India, and certain parts of Greece, namely Nigrita, Spain and the United States (Karkos et. al. 2011).

Spirulina is a highly sought-after food due to its high nutritional and protein content. Reports suggest that it contains a protein content of up to seventy (70%) per cent of its dried weight.  As such, fifty-seven-point five grams (57.5g) is said to provide over One Hundred and fifteen (115%) per cent of the daily value.  Spirulina also has all eight (8) essential amino acids, such as lysine and tyrosine (J. Simpore et. al. 2006; S. Bensehaila et. al. 2015, etc.).  

Other nutrients that make up this functional food include essential fatty acids, iron, Vitamin A (as beta carotene), vitamin E, vitamin K1, vitamin K2, thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6) and the controversial vitamin B12, calcium, iodine, zinc and magnesium, among others.  

It must be noted that the vitamin B12 that is found in Spirulina is said to be not effective in providing the human body with the necessary B12, as it is an analogue or what is called a pseudovitamin.  An analogue or pseudovitamin B12 is a molecule that resembles that of true vitamin B12 in its chemical disposition, but which is unable to be utilized by the human body (Watanabe et. al. 1999).

Spirulina is also said to have over One Hundred Eighty (180%) percent more calcium than whole milk, more beta-carotene than carrots, as well as more iron than Popeye’s favourite spinach (Moorhead K, et. al. 2005).  In addition, you may want to opt for a small serving of spirulina, which purportedly has more antioxidant and anti-inflammatory properties in just three (3) grams than eating five (5) servings of fruits and vegetables (Moorhead K, et. al. 2005). 

Another of the touted benefits of consuming spirulina is that it is recognized as a useful candidate for the removal of heavy metals from the body (A. A. Al-Homaidan et. al. 2015; A. Celekli, M. et. al. 2010; L. Fang, C. Zhou et. al. 2011).

Due to its wealth of nutrients, it is reportedly used as a food source in some African regions, especially in times of famine.  According to reports, it served as the only source of nutrition during periods of famine in some African communities and was thus eaten for over a month at a time (Capel and Cysewski, 2010).  Additionally, spirulina does not have any cellulose walls, which makes it easily digestible by the body (J. C. Dillon, et. al. 1995).

In this article, we will be exploring five (5) scientific health benefits of spirulina, which include its ability to boost and protect the immune system, its anti-viral properties, its impact on cardiovascular and diabetes health, as well as its reported anti-cancer properties.  We will also discuss its noted side effects, who should avoid it, and how to add it to your diet, as well as explore if it is a good source of vitamin B12, as may have been purported.

You can read more on some additional nutritional powerhouses, with similar benefits to spirulina, here:

• Moringa – Nature’s Multivitamin without a Bottle – Here are Five (5) Researched Reasons Why!
• Is Ginger truly great for our health? Here are five (5) researched Reasons that say it is!

5 Science-Backed Benefits of Spirulina

While spirulina is often marketed as a “superfood,” its growing popularity is not based on hype alone. Over the years, a number of scientific studies have examined its nutritional composition and physiological effects, revealing several potential health benefits that extend beyond basic nutrition.

Rich in protein, essential vitamins, minerals, and bioactive compounds such as phycocyanin, spirulina has been shown to exhibit antioxidant, anti-inflammatory, and immune-supporting properties. These characteristics make it a subject of interest in the prevention and management of various chronic conditions, including metabolic disorders and cardiovascular disease.

In the sections that follow, we will explore five science-backed benefits of spirulina, highlighting what current research suggests, while also acknowledging where further evidence is still needed. As with any functional food or supplement, understanding both its potential and its limitations is key to making informed health decisions.

1. Spirulina and the Immune System

Spirulina has been touted to have an immunostimulating effect on humans, as well as in chicken and even fish (Blinkova LP et al. 2001).  As such, it is purported to be able to enhance the body’s response to infections as well as stimulate the production of antibodies and cytokines whenever the body comes under any threat, particularly viral (Gemma, 2002).  It was also proven effective against viruses such as human immunodeficiency virus (HIV), herpes, influenza, etc. (Blinkova LP et al. 2001).

Spirulina’s immune system-protecting ability was observed in a study conducted in Japan.  In this study, the participants were given a hot-water extract of spirulina. One finding of the study showed a significant improvement in important immune system markers by analyzing the participants’ blood. As such, the researchers posited that spirulina increased the effectiveness of the immune system, which then suppressed the development of cancer and viral infections (Hirahashi T. et. al. 2002).  

But how did spirulina cause such suppression?  Well, according to the researchers, the spirulina extract had a greater level of what is called ‘natural killer cells interferon gamma’ and as such, was able to signal the body’s response via ‘toll-like’ receptors in the blood cells (Hirahashi et. al. 2002).

Toll-like receptors are a category of proteins that play a critical role in the body’s natural immune system response (Hirahashi et. al. 2002).  The immune-enhancing effects of spirulina are largely due to its phycocyanin properties, which are also found in other blue-green microalgae (Hirahashi et. al. 2002). Phycocyanin is a water-soluble blue pigment that gives spirulina its rich, vibrant colour (Nemoto-Kawamura et. al. 2004).  

It is also a potent antioxidant which has both immune-boosting and anti-viral properties (Nemoto-Kawamura, et. al. 2004).  According to research, phycocyanin enhances the body’s biological defence when it comes under attack due to an infectious disease (Nemoto-Kawamura, et. al. 2004).

2. Spirulina and its antiviral properties

The unique nutrient profile of spirulina has helped it to play a vital role as an anti-viral food source (Capel and Cysewski, 2010).  Spirulina’s anti-viral potential was found in a study conducted in Japan in the 1990s.  In this study, the researchers used an isolated sulfated polysaccharide compound found in spirulina.  They named this compound – Calcium Spirulan.

Calcium Spirulan was found to be effective against several viruses, such as herpes simplex type 1, measles, mumps, influenza A and HIV-1.  The Calcium Spirulan was said to prevent the virus from penetrating the cells of the body (Hayashi et. al. 1996).  Calcium Spirulan was also found to be more effective against HIV-1 and herpes simplex type-1 than the more commonly used anti-viral dextran sulfate (Hayashi et. al. 1996).  As such, the researchers concluded that calcium spirulan could be considered an alternative anti-HIV therapeutic drug (Hayashi et. al. 1996).

Another report by Teas J et. al. (2004), which was a paper that came from those same studies in Japan, noted that the regular consumption of algae may be able to prevent the replication of HIV.  As such, countries and groups which consume algae foods have low rates of HIV infections, even in Africa, where it is said that the highest rates of this type of infection are found (Teas J et. al. 2004).  

For example, the researchers pointed out that Chad, a country in Africa, reportedly had a low rate of HIV/AIDs when compared to the rest of Africa.  This, according to the researchers, is due to one of Chad’s large tribal groups (the Kanemba), which eat spirulina daily, consuming an average of three (3) to thirteen (13) grams per day.  As such, frequent consumption is said to help prevent HIV infections and thus reduce the viral loading of those who are already infected with the condition (Teas J et. al. 2004).

3. Spirulina and Cardiovascular Health

Several studies have noted that spirulina may have a beneficial effect on the prevention of cardiovascular diseases (Capel and Cysewski, 2010).  This is because the oral consumption of spirulina was found to reduce blood pressure and the concentration of plasma lipids, especially low-density lipoprotein cholesterol (LDL), as well as triacyl-glycerols (Juarez-Oropez et. al. 2009). 

The consumption of spirulina was also shown to indirectly alter one’s total cholesterol as well as high-density lipoprotein cholesterol (HDL) values (Juarez-Oropez et. al. 2009).

In a double-blinded randomized trial conducted in Korea by Park et. al. (2008), it was found that spirulina may be able to reduce one’s cholesterol.  This study was conducted with seventy-eight (78) elderly men and women between the ages of sixty (60) and eighty-seven (87) years. It was found that spirulina consumption lowers the cholesterol levels of the participants when compared to the placebo group, as well as increases important markers of immunity and the body’s antioxidant capacity. 

The research also found that spirulina could potentially positively impact the lipid profiles in healthy, elderly males and females.  As such, the researchers concluded that spirulina could serve as a suitable functional food.

Spirulina was also found to be effective in persons with a particular kidney condition.  This study was conducted with twenty-three (23) persons who were suffering from a condition known as – hyperlipidemic nephrotic syndrome.  Nephrotic syndrome is described as damage to the kidneys.  The participants were divided into two (2) groups, with one group receiving only medication for nephrotic syndrome, while the other group received the medication plus one (1) gram of spirulina per day for two (2) months.  

The researchers found that total cholesterol, low-density lipoprotein cholesterol (LDL-C) and triglycerides decreased significantly in the group that took both the medication and spirulina than in the other group.  The researchers noted that total cholesterol in this group decreased by Sixty-five (65%) percent, with LDL-C decreasing by up to Fifty-four (54%) per cent in the group that consumed the spirulina.

According to research, essential fatty acids such as Gamma Linoleic Acid (GLA) can prevent cholesterol from concentrating in the body.  As such, spirulina, which has a high amount of GLA, makes it an excellent candidate to combat conditions that are caused or aggravated by high cholesterol.

To this extent, the researchers purport that spirulina capsules from spray-dried spirulina are rich in antioxidants, as well as GLA, amino acids and fatty acids, and thus have the potential to reduce the possible increase of lipids in persons suffering from hyperlipidemic nephrotic syndrome (Samuels et. al. 2002).

4. Spirulina and Diabetes Mellitus

Diabetes mellitus is a chronic disease that is of global interest due largely to its socioeconomic impact (Eun et al. 2008). Research has shown that diet does play a critical role in both the prevention and management of complications.  According to Eun et al. (2008), the beneficial effects of spirulina may help to maintain the nutritional balance in persons suffering from diabetes due to its cholesterol regulatory potential as well as antioxidant and immune-modulating abilities.  As such, it could be used as a functional food for persons suffering from diabetes, especially type-2 diabetes (Ravi et. al. 2010; Eun et al. 2008).

In a study conducted by Kulshreshtha et. al. (2008) on the beneficial effects of spirulina on diabetic rats, it was found that spirulina was able to correct the abnormal carbohydrate and lipid metabolism that occurs due to the body’s exposure to excess fructose (Kulshreshtha et. al. 2008).

5. Spirulina and Cancer

While there are currently not many human clinical trials on spirulina and cancer, there exists sufficient research that has shown its potential to prevent carcinogenesis as well as to reduce tumour sizes in research conducted on animals (Capel and Cysewski, 2010).

Spirulina tumour reduction and prevention possibilities were observed in two (2) studies conducted by Harvard University School of Dental Medicine.  In the first study, it was shown that a combination of spirulina and Dunaliella extract was found to reduce tumours by thirty (30%) per cent in the animals who consumed both substances, with the remaining seventy (70%) per cent of the animals only experiencing a partial regression in their tumour growth (Schwartz J, and Shklar, 1987). 

The second study showed that both the spirulina and Dunaliella extracts were able to prevent the development of tumours in the mouth of the rodents (Schwartz J, et. al. 1988).  According to the researchers, while spirulina was not the sole substance used, the findings do suggest that the microalgae may have both a preventative and curative effect on cancer (Capel and Cysewski, 2010).  It must be noted that Dunaliella salina extract is a type of unicellular microalgae that is found in hypersaline environments, for example, salt lakes (Ben-Amotz and Avron 1987).

However, in a study with just pure spirulina, it was found that it could inhibit the formation of tumours in both the skin and stomach.  This study was conducted by Dasgupta et. al. (2001) with rodents that received either Two Hundred and fifty (250) mg and Five Hundred (500) mg/kg as per their body weight.  Both dosages had a reducing effect on both types of tumours. 

According to the researchers, the lower dosage saw a reduction in skin tumours from four point eight six(4.86) to one point two zero (1.20%) per cent and from four point eight six (4.86) to One Point one five (1.15%) per cent in rodents that consumed the higher dose of spirulina. 

A similar reduction was experienced in stomach tumours with the rodents that consumed the lower dosage of spirulina in comparison to those that were fed the higher dosage.  Additionally, more recent research conducted in 2008 found that the consumption of pure spirulina alone had a preventative effect on induced genetic cell damage (Chamorro-Cevalls et. al. 2008).

 Is Spirulina a good source of Vitamin B12?

Research says ‘No.’ According to research, the vitamin B12 that is found in Spirulina is called a pseudovitamin and is ineffective for human consumption (Watanabe et. al. 1999).  Pseudovitamin B12 is a substance that does not meet the accepted definition of a vitamin that is required for human consumption (medical-dictionary.com). 

As such, it is recommended that you do not consume spirulina with foods that have active vitamin B12, as the analogues of vitamin B12 can interfere with its absorption, which could cause a deficiency in the long run. 

So, wait a while before using your spirulina products when consuming foods high in this nutrient.  Active vitamin B12 can be found in foods such as dairy and eggs, as well as in meats and fish.  These sources of vitamin B12 have been denoted as bioavailable to humans.  However, if you are a vegetarian, then you might have to supplement with vitamin B12, as research contends that this vitamin is not found in plant sources.

What are the side effects of consuming Spirulina?

Microalgae in general have been used for years as a dietary supplement without any significant side effects (Karkos et. al. 2011).  However, some noted side effects of consuming spirulina include nausea, vomiting, feeling dizzy, headache and even diarrhoea (medicineplus.gov).  Further, some spirulina products might be contaminated with toxins and contaminants such as microcystins.  Microcystins are considered general liver toxins (Slatkin et. al. 2002; Adams et. al. 1988).

Contaminated spirulina can cause serious health problems, which can even lead to death.  As such, research has shown that an injection of a lethal dose of microcystins could cause liver damage and cell death in as little as Twenty (20) minutes (Slatkin et. al. 2002; Adams et. al. 1988) and death, within One Hundred and Sixty (160) minutes (Yoshida et. al. 1997). 

It must be noted that the lethal dose was not listed in the research; However, the doses that caused death in the mice that were used in the study were oral doses of 16.8 and 20 mg/kg, respectively. So, always ensure that the products you purchase are those that have been tested and proven to be free of toxins and other contaminants. 

Additionally, remember to consult with your healthcare provider before taking this or any other supplements.

Can I take Spirulina every day?

Several toxicology studies have reported spirulina as safe to consume frequently.  In fact, it is listed by the US Food and Drug Administration (FDA) under the category GRAS, which stands for Generally Recognized as Safe (Karkos et. al. 2011). 

However, most research has only been conducted over durations of up to twelve (12) weeks.  As such, long-term use must be cautioned, as no study has shown that it has been used for longer periods.  Best to be safe!

Who should avoid taking Spirulina?

Uncontaminated spirulina is said to be safe for most people in the short term.  However, pregnant or breastfeeding women should avoid it due to the possibility of it being contaminated (medicineplus.org).  It is also reportedly unsafe for children who are purported to be more sensitive to contaminated products. 

Persons who suffer from auto-immune conditions (i.e. lupus, multiple sclerosis (MS) and rheumatoid arthritis.  Consuming spirulina with these conditions may cause the immune system to become more active, which could worsen symptoms (medicineplus.org). 

Additionally, if you are on blood sugar medicines, consuming spirulina along with these medications could cause your blood sugar to drop too low.  As such, consult your medical provider for guidance or simply avoid taking it(medicineplus.org). 

It is also recommended that you stop taking spirulina at least two (2) weeks before a scheduled surgery.  This is because spirulina may slow blood clotting, which can increase the risk of bleeding (medicineplus.org).  

Once more, remember to consult with your healthcare provider before taking this or any other supplements.

How to add Spirulina to your diet

Spirulina is usually sold as a supplement and thus can be found in tablet, capsules and powder formats, which seem to be two of the most popular choices.  Powdered forms may offer greater flexibility for use in smoothies and recipes, while tablets and capsules provide convenience and precise dosing. The choice ultimately depends on personal preference and lifestyle.

Remember, spirulina carries a potent earthlike taste; As such, you can add fruits to your smoothie recipes to mask its strong taste. Some of the fruits you can add include mangos, pineapples, bananas, etc.

What to look out for when purchasing Spirulina?

One of the best recommendations offered as it relates to purchasing your spirulina supplement is to check on how the product was produced and if the brand has been tested by a third-party organization (i.e., U.S. Pharmacopeia (USP), Consumer Lab or NSF International, among others).  Ask questions if needed about the company selling or having manufactured the product.  

Select products from reputable brands with positive reviews and a history of quality manufacturing practices. Transparency, clear labelling, and accessible customer information are often indicators of a trustworthy company.

The aim is to ensure that the product is produced in a safe and conducive environment and is free from contaminants such as microcystins or other toxins.  Also, purchase your product from a trusted brand, but always check to see if production has changed, to ensure that you are purchasing the product as expected.

Ensure that the product is properly packaged to protect it from moisture and light, which can degrade its nutritional quality over time.

Choosing a high-quality spirulina supplement not only enhances its potential benefits but also minimizes the risk of exposure to harmful contaminants. As with any supplement, it is advisable to consult with a healthcare professional, particularly for individuals with underlying health conditions or those taking medication.

Nonetheless, please bear in mind that, even with the best of tests and intentions, a certified product may not be completely free (100%) of contaminants.  This is due to the fact that dietary supplements remain largely unregulated.  So, always do your checks before purchasing.

Illustrative Summary

Here is a summary of SPIRULINA SCIENTIFIC BENEFITS.

 Let’s Sum Up!

Spirulina is a highly nutritious and eco-friendly microalgae that is considered a functional food due to its many purported health benefits.  Some of the health benefits of spirulina include its ability to boost and protect the immune system, its effects on diabetes, and its cardiovascular health benefits. 

These and other benefits are due to its high nutritional content, such as protein, which it contains in abundance, Gamma Linoleic Acid (GLA), vitamins and minerals such as vitamin A in the form of beta carotene, B6, zinc, and magnesium, among many others.

Spirulina can be found in capsules as well as powdered forms.  Both forms are beneficial to human health based on numerous studies.

So, have you ever consumed spirulina or planning to? How was it? Share it nuh!

You can read more on some additional nutritional powerhouses with similar benefits to spirulina.

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• Video: Let’s Talk Spirulina
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Editor’s Note: This article was last updated by a Researcher and Certified Nutrition Coach on April 14, 2026.