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Health Benefits of Spirulina

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This ancient algae antioxidant is good for your heart, mouth and more

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Person adding spirulina powder to a blender

Spirulina, a type of algae, has been lauded for centuries for its high nutritional value, being called, among other things, one of the “most nutrient-dense foods.” Believed to have first been used in ancient Aztec civilizations, spirulina has more recently been used as a dietary supplement for NASA astronauts on space missions.

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Spirulina comes from a blue-green algae plant found in oceans and salty lakes. It’s typically sold as a powder, capsule or tablet supplement. Spirulina is rich with good-for-you nutrients, like:

  • Iron
  • Beta-carotene
  • Thiamine (vitamin B1)
  • Riboflavin (vitamin B2)
  • Niacin (vitamin B3)
  • Copper
  • Magnesium

One tablespoon of spirulina includes:

“Spirulina is considered one of the oldest plants on Earth,” says registered dietitian Beth Czerwony, RD, LD. “It’s been used by people for a very long time and has been shown to have some very exciting health benefits.”

You may have also heard of blue spirulina. Blue spirulina benefits are the same as spirulina but include a higher concentration of phycocyanin, an antioxidant that gives the algae its bright hue.

There is a growing body of research supporting spirulina’s positive effects on people. Even more benefits have been shown in lab studies that may translate to humans. Czerwony says the evidence so far points to several reasons to be excited about spirulina’s health benefits.

People are always raving about the antioxidant effects of blueberries, avocados, salmon and more. You can add spirulina to that list.

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“Antioxidants have this wonderful ability to go in and beat up on free radicals, which are essentially poisons that we come into contact within our everyday lives,” Czerwony explains. “Antioxidants reduce inflammation in our bodies, which can decrease the chances of a whole host of diseases.”

Spirulina’s antioxidative properties are among the reasons it’s used by astronauts. (Interestingly, inflammation has been shown to be a major health risk of space life.)

Spirulina’s anti-inflammatory properties have been shown to have some impressive benefits for your heart. A meta-analysis shows that spirulina may improve blood cholesterol and triglycerides.

“When we think about anti-inflammatory foods, we’re always thinking about heart health because we know that inflammation can lead to plaque formation and hardening of the arteries,” Czerwony says. “So, if you already have high cholesterol, there’s some promise that spirulina is going to help. It could also potentially be used proactively if you’re at risk for heart disease.”

Additional research shows that spirulina may also help reduce and prevent high blood pressure.

If you’re allergic to pollen, ragweed, animals and more, research has shown that regular use of spirulina may help relieve your runny nose.

“This is a really interesting finding because seasonal allergies are quite common, and some people don’t tolerate allergy medications well or would just prefer a more holistic option to control their symptoms,” Czerwony notes.

Spirulina is antimicrobial and antibacterial (meaning it can kill off — or at least stop the growth of — bacteria and other invaders).

One study put its germ-killing power to the test with spirulina-laced mouthwash. Results showed people who swished with spirulina showed “significant reduction in dental plaque and gingivitis (gum disease).”

There’s also research around how spirulina — and its ability to reduce oxidative stress — may play a role in improving muscle strength and endurance. Another study shows that the algae may improve oxygen uptake (also known as VO2).

“Human studies have shown improvement in immunity and brain health by increasing the production of antibodies that can help ward off infection and chronic diseases,” says Czerwony.

A meta-analysis of four studies shows that spirulina may aid in weight loss and reduce body mass index (BMI).

“The human studies were in conjunction with a reduced calorie intake and exercise, so it may be that spirulina has appetite suppressing abilities or it was the diet/exercise independently causing the weight loss,” explains Czerwony. “The studies are relatively small, so results should be cautiously reviewed and would warrant the need for a larger sample size.”

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The U.S. Food and Drug Administration (FDA) doesn’t approve (regulate) supplements. But it does regard spirulina as “generally recognized as safe.”

If you’re looking to add spirulina to your life, you’ll want to go easy on it. It’s recommended to take no more than 8 grams of spirulina per day — that’s a little more than two teaspoons. You may experience some mild side effects like:

But for all its promising effects, spirulina may not be a good choice for everyone, Czerwony cautions. You should talk with a healthcare provider, like your general practitioner or a nutritionist, before taking spirulina.

That’s because there are some people who should avoid spirulina or at least be wary of it. That includes people who:

  • Are pregnant or breastfeeding
  • Have a compromised immune system
  • Have diabetes
  • Have a blood disorder
  • Are allergic to shellfish or other seafood
  • Have an intolerance to iodine
  • Are living with phenylketonuria (PKU) — a rare genetic condition where you have a buildup of the amino acid phenylalanine

Spirulina powder can be added to your favorite smoothie, or you can try sprinkling it in your guacamole, hummus or pesto. The FDA also approves the use of spirulina as a colorant and to be used in foods like cereals and beverage mixes.

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But some people are put off by the taste of spirulina, even in small amounts. Remember, it’s a sea plant, so the taste can be described as earthy or fishy, which may not be for everyone.

If the taste of spirulina isn’t your jam, Czerwony suggests talking with a healthcare provider about over-the-counter spirulina supplements instead.

“Whole foods are always the preferred source of nutrients,” she adds. “But if you can’t tolerate the taste of it, the capsule form is a good alternative.”

When you consider the potential benefits of spirulina, you can see why many consider it a “superfood.”

While the research is promising, Czerwony stresses that more human studies are needed to confirm spirulina’s advantages. Lab studies have also considered how spirulina may:

  • Improve eye health
  • Improve immune health
  • Improve gut health
  • Support brain health
  • Fight against anemia
  • Reduce cancerous tumors

“Focusing on a healthy, well-balanced diet should be the first step to improve your health and decrease getting or increasing the progression of chronic disease,” concludes Czerwony. “A ‘food first’ approach is much more effective and someone should not rely on supplementation alone.”

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Related questions

01By the way, doctor: Is spirulina good for you?

Q. I haven’t much about spirulina recently. What can you tell me about it? A. Spirulina — classified as a cyanobacteria, or blue-green algae — has been used for centuries as a food source in other countries. Spirulina is available in capsules, tablets, and powder and has been incorporated in certain foods and beverages such as energy bars, popcorn, and smoothies. An Internet search returns hundreds of suppliers from around the world promoting spirulina's supposed health benefits. Spirulina can grow in extreme conditions inhospitable to most other water-dwelling organisms. It's generally cultivated in manmade or natural lakes, harvested, and freeze-dried. Spirulina boasts a 60% protein content — it's a richer source of protein than most vegetables — and it's also a good source of beta-carotene, various minerals, and gamma linolenic acid, an essential fatty acid. While the makers of spirulina supplements tout their positive health effects, the scientific evidence doesn’t support it. Admittedly little research has been done recently on spirulina. Like other dietary supplements, spirulina is not regulated by the FDA, so there's no guarantee that the product you buy will be contaminant-free or contain the amount of spirulina promised on the label. Few side effects have been reported from spirulina when used at recommended doses. But it may worsen symptoms of an autoimmune disorder and can interfere with blood clotting. Most importantly, this type of algae theoretically could contain the amino acid phenylalanine and thus should be avoided by people who have phenylketonuria (PKU) — a metabolic disorder in which the body can't metabolize phenylalanine. If you're using spirulina, let your health provider know, as it could interact with other medications you might be taking. Image: © SKunevski | iStock/Getty Images Plus

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Peptide Therapy Guide Editorial Team

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