6 Spirulina Health Benefits—Plus, Recipes and When to Avoid It

This blue-green algae powder delivers on nutrition.

Spirulina, a blue-green edible algae you'll likely find in a powdered form, used to be available only in health-food stores, but it's now infiltrating supermarkets everywhere. Though spirulina has been consumed as a food source for hundreds of years in cultures around the globe, it's only now becoming a health food du jour in the United States. Here's what you need to know about spirulina, its promising health benefits, and how you can incorporate this newly minted superfood into your diet.

What Is Spirulina, and Where Is It From?

Spirulina, or Arthrospira, is an alga (the singular form for "algae") that's been used across cultures for centuries. The Aztecs in Mexico, for example, used spirulina as a food source and to treat various diseases. Spirulina is used in much the same way today—it's even made its way to space as a dietary supplement for astronauts on NASA missions.

Now, it appears everyone wants to get their hands on this nutrient-dense freshwater plant. According to KBV Research, the global spirulina market is expected to reach $651 million by 2025. Spirulina can bloom and grow naturally in alkaline lakes around the world. However, companies are now lab-growing these algae (which have an earthy, seaweed-like taste) in massive tubes to ensure enough supply for the growing demand.

Overhead view of glass with chlorella drink, spirulina and chlorella powder and tablets on a pink background
Getty Images

Spirulina Nutrition Benefits

Emmie Satrazemis, RD, board-certified sports nutritionist, registered dietitian, and nutrition director at Trifecta, believes spirulina deserves a spot in a healthy diet. She points out that this naturally vegan food is packed with nutrients. Here are some of the health benefits of spirulina that make it such a promising new superfood.

1. Spirulina is a good source of plant protein.

According to Satrazemis, spirulina "is a fairly protein-dense and low-calorie" food. Just 1 tablespoon of spirulina, she adds, contains 25 calories, 0.5 grams of fat, 1 gram of carbs, and 4 grams of protein—making it protein dense.

2. Spirulina delivers essential vitamins and minerals.

"It contains notable amounts of calcium, niacin, potassium, magnesium, B vitamins, and iron," Satrazemis says. Spirulina is particularly high in vitamin B12, which helps make up your DNA and is key for supporting healthy blood and nerve cells. It's also an especially good source of iron, providing about 2 grams per 1 tablespoon.

3. Spirulina contains plant compounds that help protect eye health.

"Spirulina is also a notable source of phytonutrients—plant-based compounds (in this case, plant pigments) that are thought to provide protective health benefits," Satrazemis says. More specifically, spirulina is rich in a certain group of phytonutrients called carotenoids.

Per a Harvard University study, carotenoids are beneficial for both eye and immune health. A pair of the most common carotenoids—lutein and zeaxanthin—are found in the retina and may decrease your risk of developing macular degeneration by up to 43 percent.

4. Spirulina offers important fatty acids.

Overall, spirulina is low in fat, but it is a plant-based source of omega-3 fatty acids and omega-6 fatty acids, including gamma linoleic oleic acid. According to numerous studies, omega-3 fatty acids can help fight depression and anxiety, protect the brain from age-related cognitive decline, and promotes brain health during pregnancy and early life, to name a few of its health benefits. Aside from giving your brain a boost, omega-3 fatty acids can also improve risk factors for heart disease, fight inflammation, and improve bone and joint health.

5. Spirulina is full of antioxidant plant compounds that fight inflammation.

Spirulina contains a high concentration of bioactive plant compounds, including polyphenols and plant pigments, which have important antioxidant and anti-inflammatory effects in the body, helping to protect your cells against free radical damage and oxidative stress that can lead to inflammation and disease.

6. Spirulina may be helpful in promoting healthy gut bacteria growth.

Older in vitro research and animal studies suggest that this water plant can help support gut health with the ability to improve the growth of probiotics (healthy gut bacteria).

Side Effects, Safety, and Reasons to Avoid Spirulina

"Spirulina has been found to be an anticoagulant, or blood thinner, so if you have any clotting disorders, it’s always best to discuss trying spirulina with your healthcare provider first," says Christina Manian, RDN.

She also adds that spirulina is high in the amino acid phenylalanine, so it should be avoided by those with phenylketonuria (or PKU), a rare genetic metabolic disorder that makes the body unable to break down the specific amino acid phenylalanine.

"Spirulina, like other algae, is very sensitive to the environment in which it’s grown," Manian says. "This means it can absorb all of the healthy nutrients we’re after when consuming it, but it also means it can absorb harmful substances like heavy metals and environmental toxins."

Because of its potential to carry heavy metals and environmental toxins absorbed from its environment, spirulina may not be a good option for pregnant people. "Pregnant women should be especially diligent with researching the source of spirulina they’d like to purchase, but before even considering a purchase, I would recommend pregnant women speak with their healthcare provider," she says.

Your smartest move to avoid unwanted or harmful additives is alway to choose a spirulina supplement brand that has been third-party tested for purity standards (since these products are not tested or regulated by the U.S. Food and Drug Administration).

Where to Buy Spirulina and How to Store It

Spirulina is available in many forms, including capsules and powders. It's also baked into other items (such as bars), blended into smoothies, and can act as a topper to popcorn. Spirulina can be found in grocery stores around the world throughout the year.

It's best to store spirulina tablets and powder in the refrigerator. Though it doesn't technically go "bad," its nutritional qualities will degrade over time. Thus, it's best to consume spirulina within a few months of opening it.

Frequently Asked Questions

  • How much spirulina should you consume per day?

    "There’s no official recommendation for how much spirulina you should consume per day. However, a generally accepted dose from the research we have thus far is somewhere between 1 and 3 grams, and up to 10 grams per day,” Manian says. “A great rule of thumb is to enjoy a tablespoon of spirulina in a smoothie a few times per week.”

  • What does spirulina taste like?

    According to Manian, spirulina has a unique flavor best described as a mix of "seawater, lake water, and sulfur with a hint of earthiness. I personally don’t love the flavor, which is why I add it to smoothies," she says, "you can barely tell it’s there!"

  • Should you take spirulina in the morning or at night?

    "While there’s no caffeine in spirulina, the protein and B vitamins in particular may [energize you], which [makes it] a great way to start the day, but could potentially interfere with a good night’s sleep," Manian says. "However, spirulina may not have that effect on some people, so I recommend experimenting and seeing what works best for you."

  • Is spirulina safe during pregnancy?

    "Because of the potential for spirulina to absorb heavy metals and environmental toxins, I would recommend pregnant women speak with their healthcare provider and be especially diligent researching the source of spirulina they’d like to purchase," Manian says.

3 Spirulina Recipes

As you may have guessed, if you wish to incorporate some spirulina into your diet, you can add the nutritious algae to just about anything. Keep reading for a few healthy recipes that could benefit from a bit of spirulina.

Overhead view of three raspberry smoothie bowls displayed on a floral tablecloth
Christopher Testani

Raspberry Smoothie Bowl

Blend a teaspoon of spirulina into this vibrant smoothie bowl made with a banana, frozen raspberries, almond milk, vanilla extract, and more. If you're not sure if you'll like the earthy taste of spirulina, this is a great way to give it a try as you get used to its bold flavor.

Chickpea "Cookie Dough" Bites on White Plate
Victor Protasio

Chickpea "Cookie Dough" Bites

These no-bake "cookie dough" bites are made with chickpeas (yes, those chickpeas) but taste eerily similar to oatmeal raisin cookie dough. To give your dough bites a bit of an earthy flavor—which will complement the chickpeas—add a dash of spirulina to the recipe.

Green Smoothie in a Glass
Caitlin Bensel

Good Morning Green Smoothie

This smoothie is already green and packed with healthy fruits and vegetables (think apples, spinach, and Persian cucumbers), so chances are you won't even notice if you add a teaspoon or two of spirulina to the mix.

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