Spirulina Benefits, Nutrition, Facts, and Side Effects

Spirulina is a superfood that is made of a blue-green alga (cyanobacterium) found in fresh and marine water around the world.

Yes, the most concise answer to “What is Spirulina?”, is algae.

But don’t be too quick to get grossed out. 

When harvested in the right environment, this algae is one of the most nutritionally concentrated foods known to humankind with an absurdly high content of complete protein, the B, K, A, vitamins, omega 3s, and antioxidants. 

Spirulina has a long history as a food source, enjoyed the Aztecs, the natives in Chad, Africa, and others. 

It surged in popularity again when NASA named spirulina as a dietary supplement for astronauts in space and exalted the quality of spirulina nutrition (1).

Today, spirulina, a relative of chlorella and kelp is one of the most studied superfoods with many proven health benefits to speak of (2).

To consume, spirulina is rarely available as is, but most commonly made into spirulina powder or tablets

In this post, we’ll take a look at what spirulina is good for and why it’s the most powerful superfood to eat. 

Here are the top 16 spirulina health benefits, all backed by science.

Spirulina Benefits, Nutrition, and Facts.

This infographic highlights 14 of the top benefits of spirulina.

1. Spirulina is Highly Nutritious

Spirulina is one proven superfood with an incredible amount of vitamins and minerals. 

Compared to some of the most nutritious plant-based foods, gram per gram, spirulina has:

  • 2,800 % more beta-carotene than carrots (good for eyes, stronger immunity)  
  • 3,900 % more iron than spinach (increases energy and good for blood health) 
  • 600% more protein than tofu (helps builds muscle tissues) 
  • 280% more antioxidant potency than blueberries (good for cellular health and immunity) 

Here is also another look at Spirulina’s nutrition profile per one teaspoon (3g) (2):

  • Protein: 2 g
  • Vitamin A (Beta Carotene): 300% of the RDA (2715 mcg) 
  • Vitamin K (K1, K2): 30% of the RDA (40 mcg)
  • Vitamin B12: 290% of the RDA (7 mcg)
  • Iron: 30% of the RDA (5 mg) 
  • Manganese: 10% of the RDA (0.2 mg) 
  • Magnesium: 4% of the RDA (15 mg)

For those cautious of calories, spirulina is nearly calorie free, coming with 10 calories per serving (1 teaspoon). 

Gram per gram, spirulina is one of the most nutritious foods on earth. 

2. Provides Quality Protein

Spirulina offers complete protein, containing all the essential amino acids in addition to some non-essential ones. 
While meats are often considered the foods highest in protein, they are also high in calories, fat, and cholesterol. 

According to Harvard Health, consumption of red meat has been linked to a higher risk of type 2 diabetes, heart disease, stroke, and certain cancers (3).

Spirulina, on the other hand, is almost free of calories, fat, and cholesterol, only containing 10 calories, 5 % fat, and practically zero cholesterol. 

Protein in spirulina is also more digestible than other proteins. Compared to beef’s 16% and fish’s 18%, protein usability, Hawaiian Spirulina scored 37% (2).

This uniquely high protein usability comes from Spirulina’s softer cell walls made of soft mucopolysaccharides. This makes it easy for the body to digest and absorb the protein, a factor particularly of importance to elderly and undernourished people. 

According to the protein usability study, the only food with more usable protein than Spirulina is eggs, which has 44% usable protein. (2)

3. Provides Powerful Antioxidant and Anti-Inflammatory Properties 

Oxidative damage is harmful to our cells and can cause chronic inflammation that may lead to diseases such as cancer (4).

Spirulina is a rich source of antioxidants that fight against free radicals and protect the cells from oxidative damage.

While there are several antioxidants found in spirulina, phycocyanin, a pigment responsible for its blue hue, is known to contain antioxidant and anti-inflammatory properties according to some studies (5, 6, 7).

Spirulina’s other pigments with antioxidant power include chlorophyll, which produces green color and is responsible for detoxification, beta carotene for orange, and zeaxanthin for yellow, particularly known for its aid for eyes and brain. 

4. Rich in Minerals 

While vitamins often take the spotlight when it comes to nutrition, minerals are just as essential to your body as vitamins and other nutrients.

Minerals generate tiny electrical impulses that enable muscles and the heart to function. 

Your brain is also supported and enabled by those electric impulses. 

Traditionally, plant foods such as grains, vegetables, and fruits, grown in nutrient-rich soil were the primary provider of those minerals, but as modernization of agricultural practices advances, the deprivation of nutrients in soils has also been taking place (9). 

Despite, Spirulina, especially the Hawaiian Spirulina remains to be a rich source of trace minerals been grown in a pond 2,000 feet underwater, where trace minerals like zinc, iron, copper, iodine, and manganese have settled.

Spirulina grown in Hawaii takes advantage of the mineral-rich environment, absorbing these minerals and make them available in the human body when consumed (2).

5. Spirulina Boosts Your Immune System

Spirulina is known to boost the immune system and brings year-round protection. 

Ideally, your good health supports your immune system and keeps your body responsive all year-round. 
But should your immune system fall, spirulina is there to offer the safety net with an array of vitamins and minerals. 

In fact, increased energy and immune system are one of the top health benefits of spirulina. 

This is also well documented in a study conducted on 200 Hawaiian Spirulina users with various usage patterns, some taking the recommended dosage daily while others taking less frequently.
Of those Spirulina users, 77% reported an improvement in their immune system. 80% reported more energy (2). 

In another study on Spirulina’s effect on the immune system, 40 participants aged over 50 took 3 grams of Hawaiian Spirulina for 12 weeks.

He measured the difference in the immune system strength measuring two markers of immune systems – white blood cells and certain liver enzymes. Both improved with Spirulina consumption (10).

6. Supports the Brain Functions

We all know that antioxidant-rich food like blueberries benefits your brain health. 

It turns out, the same researcher who studied the effect of antioxidants in blueberries studied the effects of spirulina and spinach on the brain as well and made a profound discovery.

In that study, rats were fed either spirulina, blueberries, spinach, or none of the above on a daily basis. While all the rats that consumed any of the antioxidant foods showed a heightened level of cognition, Spirulina fed rats especially had significant positive outcomes on brain scans (11).

Another study on lab rats showed Spirulina is also beneficial for protecting stem cells, which are responsible for memory, learning, and repair work on the body (12).

Although these studies weren’t done on humans, they strongly signal the potential of Spirulina supplementation on neurological functions.

7. Supports Your Kidney and Liver

Antioxidants are needed for more than your brain and skin. 

They protect the liver and kidney from being harmed by free radicals as well. 

Spirulina benefits include protection for your kidney and liver by offering a powerful antioxidant, phytonutrients, which is known as fast to act and reach to the areas of the body where more of antioxidants are needed to fight off the oxidations.

In a study performed on rats, this correlation between spirulina and the performance of liver and kidney cells confirmed the consumption of spirulina leads to an increased ability in withstanding oxidation (13, 14). 

8. Helps Support Pregnancy and Breastfeeding

Pregnant women and breastfeeding mothers are especially in need of an increased amount of hemoglobin (blood cells) and healthy storage of iron. 

Spirulina is beneficial to those women, providing 30% of the recommended daily intake of iron in every serving. 

One study in India also confirmed Spirulina’s benefit for the hemoglobin level.

The study compared one group of women who took vitamin supplements but no Spirulina and one who received the same vitamin supplements and spirulina. The latter group who had the addition of spirulina resulted in having a higher hemoglobin level than the other group (15).

Spirulina’s iron content is essential in hemoglobin and muscle cells delivering oxygen to one’s body. 

9. Boosts Energy

Coffee and energy drinks are a popular way to boost energy.

But they tend to make you collapse mid-day with a load of sugar. 

Instead, Spirulina makes a better alternative.  

Spirulina’s synergy of its beta carotene, iron, vitamins, phycocyanin, and other nutrients, provides sustained energy – crash free. 

This is also well-tested in a physically demanding environment. In a study that compared the performance of university students on a cardio workout, one group who took Spirulina lasted 7.3% longer on the treadmill than those who had placebo supplements. The oxidative stress level in the blood of those consumed Spirulina saw a 25% decrease as well (16).

10. Burns Fat

A study in Greece also discovered daily consumption of Spirulina (6gm) can lead to increased fat loss, along with improved energy and endurance.

During the study participants’ 2 hour run, those with 6 grams of Spirulina daily supplementation saw a boost in fat oxidation rate by 10.9% (17). 

11. Improves Bone Health

Vitamin K may not get talked about as much as vitamins A, B, C, D, and E, it plays an essential role in regulating regular blood clot and promoting removal of calcium deposits in the arteries.

Because vitamin K also transports calcium to other areas of the body, it’s crucial for bone health and preservation of bone mineral density (18).

While vitamin K can be found in many leafy greens and other plant-foods such as kale, cucumber, and asparagus, 3grams of Spirulina can provide as much as 50% of FDA recommended daily vitamin K intake.

12. Reduce Heavy Metal and Radiation

Spirulina, the blue-green microalgae has soft mucopolysaccharide walls that bind heavy metals such as mercury and lead and safely sweep away and dispose of them. 

Spirulina’s mucopolysaccharide walls do this by soaking up the water around them. 

This unique function of spirulina comes quite handy in our body as it effectively detoxifies the toxins and better equip us to handle the harm of toxins. 

This detoxification effect was proven when 5 grams of spirulina was given to children in the area where a nuclear plant in Ukraine exploded. After 6 months, the children’s radiation levels were reduced by 50% for spirulina’s ability to confine toxins to its mucopolysaccharide walls (19). 

13. Supports the Heart Health 

The hardest-working organ in your body is your heart.

And for the heart, the cardiovascular system to work, it needs the arteries to pump out nutrient-rich blood throughout your body. 

In a 16-week, placebo-controlled study in Korea, the elderly participants who were given 8grams of Spirulina saw an improvement in their lipid profiles, resulting in improved cardiovascular function (20). 

14. Spirulina for Children

I know many parents are wondering if spirulina is safe to give their kiddos.

The answer is yes. Spirulina is completely safe for children, just like any other plant-based super foods as spirulina represents a complete vegetarian protein source. When it’s sourced safely, it can be a fantastic all natural supplementation for both adults and children. 

I add a tablespoon to my 6-year daughter green smoothie every morning for extra nutritional boost, and I have been doing it for some time now.  

The only word of caution I have for you is to be picky with the brand of spirulina. My best and only choice for me is Hawaiian Spirulina, and I would cautiously avoid ones from regions I’m not versed in its environmental conditions and harvest practice standards. Be sure to feed your child the spirulina from the brand you can trust. 

15. Spirulina Side Effects

Are Spirulina supplements safe?

Due to its long history of being used as a food source, many health experts consider spirulina to be generally safe.

However, when purchasing a spirulina supplement, make sure that it comes from well-known, organic sources.

Inferior products have been known to be contaminated with harmful bacteria and toxic metals due to being grown in unsafe conditions. 

These contaminants can cause nausea, vomiting, weakness, thirst, shock, rapid heartbeat, liver damage, and even death. 

These inferior products are especially dangerous to children.

The National Institutes of Health highly recommends thoroughly researching the source of your spirulina supplement to make sure it has been properly tested for toxins and grown in well-monitored, safe conditions.

Individuals who were diagnosed with certain autoimmune disorders should avoid taking spirulina supplements.

Because it has been proven to enhance the immune system, spirulina may actually worsen the symptoms of conditions such as lupus, multiple sclerosis, rheumatoid arthritis and various other conditions that have been linked to an overactive immune system.

It has also been known to weaken the effects of immunosuppressive drugs.

Spirulina may also weaken the effect of blood thinners or nonsteroidal anti-inflammatory pain medications (NSAIDS).

If you are looking to supplement your diet with a good quality source of nutrients, proteins, and amino acids, spirulina is a great choice.

It is beneficial for not only adults but ideal for growing children to ensure they are consuming enough nutrients for optimal growth.

16. Where to Buy Spirulina

Where Spirulina powder and tablets are available at a wide variety of health stores and online stores and fairly accessible; not all brands carry Spirulina grown in the most ideal, safest environment where Spirulina is nutritionally well nourished and minerals are absorbed.

For high quality and nutritious Spirulina to grow, it takes the purity of water and pollution free air that clears the Spirulina from being contaminated with toxicity. 

One of the very few locations known as the most ideal for Spirulina harvesting is Hawaii. It has a rare combination of the environmental purities and water used for the growth comes from 2,000 feet below the surface where minerals are rich and free of pollutants. To acquire all nutritional benefits noted in this post can be acquired with consumption of such high-quality Spirulina.

How to Take Spirulina

Nutrition experts at the University of Maryland Medical Center state that a standard dose of spirulina for an adult is roughly four to six 500mg tablets per day (21).

Due to the taste of powdered or flaked spirulina supplements, tablets are the most popular choice.

However, if you use spirulina in powdered or flaked forms, such as an ingredient in smoothies, be sure to read the dosage label to ensure you consume enough.

Other related superfoods:

  • Chia seeds
  • Green tea
  • Turmeric

(2) Cysewski, Gerald R. Hawaiian Spirulina. Kailua-Kona, Hi, Cyanotech Corporation, 2016.

Misato Alexandre


After making healthy living a priority, Misato lost over 20 lbs in less than 90 days. Instead of weight loss being a dreading experience, living the lifestyle of health and fitness granted her more happiness and joy than ever before. She co-founded Fitwirr to make health and fitness simple for everyone and share her tips through writing evidence-based articles on nutrition, weight loss, and exercise.

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