Spirulina: Are There Health Benefits?

Reviewed by Dan Brennan, MD on October 06, 2020

Spirulina is a blue-green algae, and is believed to be one of the oldest life forms on Earth.

First used by the Aztecs as an endurance-booster, spirulina is considered a superfood — an all-in-one source of nutrients including protein levels comparable to eggs. 

The Aztecs also used spirulina to treat various diseases, and legends say that the kingdom’s messengers used the algae to sustain their marathon runs. Modern research supports many of the alleged benefits of taking spirulina, and continues to study its potential for treating health concerns. 

Spirulina has a bitter taste, so people often mix it with yogurts, juices, and smoothies to improve its flavor. Spirulina is commonly available as a supplement at health food stores. 

Nutrition Information

One tablespoon of spirulina contains: 

  • Calories: 20
  • Protein: 4 grams
  • Fat: 1 gram
  • Carbohydrates: 2 grams
  • Fiber: 0 grams
  • Sugar: 0 grams

Spirulina is a good source of: 

Spirulina also contains magnesium. This mineral supports normal daily functions like muscle use and your heartbeat. It’s also responsible for producing protein and creating energy — but most people don’t get enough in their diet. 

Potential Health Benefits of Spirulina

Spirulina is a potent source of nutrients. It contains a powerful plant-based protein called phycocyanin. Research shows this may have antioxidant, pain-relief, anti-inflammatory, and brain-protective properties. 

This antioxidant and other nutrients in spirulina are linked with several health benefits: 

Anti-Cancer Properties

Many antioxidants in spirulina have anti-inflammatory effects in the body. Chronic inflammation contributes to cancer and other diseases. 

Phycocyanin — the a plant pigment that gives spirulina its blue-green color — has been found to not only reduce inflammation in the body, but also block tumor growth and kill cancer cells. The immune-enhancing protein is being studied for its potential in cancer treatment. 

Heart Health

Research has found that the protein in spirulina can reduce the body’s absorption of cholesterol, lowering cholesterol levels. This helps keep your arteries clear, reducing strain on your heart that can lead to heart disease and stroke-causing blo od clots

Its protein also reduces triglyceride levels. These are fats in your blood that can contribute to the hardening of arteries, increasing the risk of heart disease, diabetes, and pancreatitis

Spirulina increases nitric oxide production in your body as well, which helps your blood vessels relax. Studies show that this can reduce your blood pressure, lowering your heart disease risk. 

Allergy Relief

The anti-inflammatory effect caused by spirulina’s antioxidants may help people with allergies caused by pollen, animal hair, and dust. One study found that symptoms like congestion, sneezing, and itching were reduced significantly in participants, suggesting that spirulina may be a good alternative to allergy medications. 

Immune System Support

Spirulina is rich in a range of vitamins and minerals essential for maintaining a healthy immune system, like vitamins E, C, and B6. Research finds that spirulina also boosts the production of white blood cells and antibodies that fight viruses and bacteria in your body. 

Laboratory studies show that spirulina can fight herpes, flu, and HIV — though much more research is needed to test these effects in humans. 

May Maintain Eye and Oral Health

Spirulina is concentrated with zeaxanthin, a plant pigment that may reduce the risk of cataracts and age-related vision loss

Its antibacterial properties may also help promote good oral health. One study found that spirulina-enhanced mouthwash reduced dental plaque and the risk of gingivitis in participants. Another study showed it lowered the risk of oral cancer in people who chew tobacco. 

Potential Risks of Spirulina

Because spirulina is high in nutrient activity, you should talk to your doctor before taking it or any other supplement. It may pose health risks for some people, including:


Spirulina harvested in the wild may be contaminated with heavy metals and bacteria. In high amounts, some of these toxins may stress or damage your liver. 

Pregnancy Concerns

There is not enough research to suggest blue-green algae is safe for pregnant or breastfeeding women. Because of the toxin risk, doctors recommend that pregnant women avoid spirulina. 

Bleeding Disorders

Because spirulina can help reduce blood clotting, it may increase the risk of bruising and bleeding in people with certain bleeding conditions. 


Spirulina might affect blood sugar levels, so people with diabetes should monitor their blood sugar when taking spirulina.

Auto-Immune Diseases

Research shows that spirulina can support immune system function, but this could worsen symptoms in people with auto-immune diseases like lupus, multiple sclerosis, or arthritis. Talk to your doctor before adding spirulina to your diet if you have an auto-immune condition. 

Medication Interactions

Spirulina’s health benefits may interact with or counter certain medications' effects, including those used to treat diabetes, immunosuppressants, and blood thinners.

B12 deficiency

It’s often claimed that spirulina contains high levels of vitamin B 12, but its content is not well-absorbed by the human body. If you have a B12 deficiency — common in people with plant-based diets — you should make sure you’re supplementing from another source. 

Show Sources


The Guardian: “Spirulina: a luxury health food and a panacea for malnutrition.”

American Journal of Clinical Nutrition: “Vitamin B-12 from algae appears not to be bioavailable.”

Cardiovascular Therapeutics. “Hypolipidemic, Antioxidant and Antiinflammatory Activities of Microalgae Spirulina.”

Cleveland Clinic: “3 Vitamins That Are Best for Boosting Your Immunity.”

Cleveland Clinic: “7 Foods That Are High in Magnesium.”

Current Pharmaceutical Biotechnology: “Nutritional and Therapeutic Potential of Spirulina.”

Current Protein & Peptide Science: “C-phycocyanin: a biliprotein with antioxidant, anti-inflammatory and neuroprotective effects.”

ESHA Research, Inc., Salem, Oregon: “Spirulina.”

European Archives of Oto-Rhino-Laryngoloy: “The effects of spirulina on allergic rhinitis.”

European Review for Medical and Pharmacological Sciences: “Effects of spirulina consumption on body weight, blood pressure, and endothelial function in overweight hypertensive Caucasians: a double-blind, placebo-controlled, randomized trial.”

Free Radical Biology and Medicine. “Oxidative stress, inflammation, and cancer: How are they linked?”

International Journal of Pharmacy and Pharmaceutical Sciences: “Effectiveness of spirulina mouthwash on reduction of dental plaque and gingivitis: a clinic study.”

Journal of Cancer: “Phycocyanin: A Potential Drug for Cancer Treatment.”

Journal of Infection and Public Health: “Spirulina consumption effectively reduces anti-inflammatory and pain related infectious diseases.”

Mayo Clinic: Triglycerides: Why do they matter?

Mount Sinai: “Spirulina.”

National Institutes of Health: “Blue-Green Algae.”

Nutrition and Cancer: “Evaluation of chemoprevention of oral cancer with Spirulina fusiformis.”

The British Journal of Nutrition: “Spirulina is an effective dietary source of zeaxanthin to humans.”

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