Spirulina health benefits: what the research tells us

We do foods a disservice when we decide they’re trendy because they inevitably fall out of favor for the next big superfood. Part of it is our desire for a quick fix. For the record, it doesn’t exist.

Many “superfoods” that we dismissed because they couldn’t shrink our belly fat or cure our health problems overnight do deserve a permanent place in our kitchens—like spirulina. Spirulina is a type of cyanobacteria, a family of organisms generally referred to as blue-green algae.

Spirulina supplements are made from arthrospira (or A. maxima) and A. platensis, two kinds of microalgae. Although its moment in the sun as the health industry’s superfood darling didn’t last long, this organism has a long history of medicinal use.

The Aztecs reportedly consumed spirulina, but it was mostly forgotten until a NASA contractor suggested that it could be grown in space to nourish astronauts. We’re not going to promise it’s as tasty as Tang, but this supplement does offer many potential health benefits.

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You’ll still find spirulina in health and supplement stores, and it occasionally pops up in random trendy drinks in order to impart that gorgeous blue-green color.

But once you know all the health benefits of spirulina, you may clear out some pantry space for this nutritious supplement. And, for the record, it is incredibly nutritious. Just one tablespoon offers 4 g of protein and a decent dose of several of the B vitamins in addition to magnesium, manganese, and copper.

May reduce high blood pressure

Spirulina may lower blood pressure in people with hypertension (abnormally high blood pressure), one study found. Daily doses of 4.5 g of spirulina were able to reduce blood pressure in 31% of participants with either type 1 or type 2 hypertension.

By the end of the study, the proportion of participants in the normal blood pressure range increased by 25%. Researchers suggest this effect is due to spirulina’s ability to release molecules that dilate blood vessels (Torres-Duran, 2007).

May reduce “bad” cholesterol

High cholesterol is one of the many risk factors for heart disease—but lowering all cholesterol isn’t the way to reduce your risk.

You want to lower total cholesterol, “bad” LDL cholesterol, and triglycerides—not “good” HDL cholesterol—and spirulina may be able to do exactly that. Just 2 g per day for two months lowered “bad” cholesterol and slightly raised “good” cholesterol in one study that looked at people with type 2 diabetes. 

Another study found the same in patients with abnormally high fat in their blood; spirulina lowered their triglycerides and LDL cholesterol by 16% and 10% after just three months. This study used just 1 g per day as the dosage, though others have used dosages as high as 8 g per day (Mazokopakis, 2014).

May help prevent heart disease

Cardiovascular disease, or heart disease, is a cluster of conditions that involve the heart and blood vessels. People with heart disease may have high triglyceride levels, hypercholesterolemia (abnormally high cholesterol), or hypertension (abnormally high blood pressure).

Spirulina may lower heart disease risk by benefitting these specific areas. As we explained, this supplement may lower triglycerides, LDL cholesterol, and high blood pressure.

Lowering cholesterol levels may help you avoid atherosclerosis, a type of heart disease characterized by a buildup of plaque on the artery walls that impedes blood flow. And its effects on triglycerides and blood pressure may reduce your risk of CVD overall.

Highly nutritious and high in antioxidants

Calling spirulina nutritious is actually a bit of an understatement. In fact, it’s one of the most nutrient-dense foods out there.

One tablespoon of the supplement, or about 7 grams of spirulina, packs 4 g of protein and quality doses of vitamin A, potassium, beta-carotene, niacin, riboflavin, and magnesium. It also boasts all of the essential amino acids, making it a “complete” protein.

In addition to amino acids, it also includes fatty acids, including heart-healthy omega-3. Despite its high concentration of nutrients, spirulina does not provide vitamin B12 (USDA, 2019).

May help with anemia

Anemia is a condition in which people lack enough hemoglobin, a protein in our red blood cells that helps carry oxygen from the lungs to the rest of the body. Medical professionals can measure whether patients are anemic or not by looking at a blood test called the “mean corpuscular hemoglobin” or MCH.

In one study, over the course of the 12 weeks, there was a steady increase in the MCH of participants taking spirulina. Women’s levels seemed to increase faster than men’s, though both sexes experienced an increase, leading researchers to conclude that spirulina may be able to lessen anemia in older adults (Selmi, 2011).

May ease symptoms of allergic rhinitis

Allergic rhinitis—which you probably know as seasonal allergies or hay fever—is a cluster of conditions characterized by nasal passage inflammation. It can also be caused by things you’re allergic to other than pollen, such as dust mites and animal dander.

Symptoms typically include itchy, watery eyes, sneezing, and a runny nose. It’s well documented that spirulina helps with inflammation-driven reactions, like seasonal allergies, by blocking histamines.

And one placebo-controlled study found that spirulina successfully decreased symptoms of allergic rhinitis, including nasal discharge, sneezing, nasal congestion, and itching (Cingi, 2008).

May act as an anti-inflammatory

If you read a lot of Health Guide, you know that oxidative damage can cause negative effects throughout your body. If you’re new here, oxidative stress is caused by an imbalance between antioxidants and free radicals, by-products of chemical processes in our body.

Oxidative damage is the harm caused to cells by this imbalance. And oxidative stress can lead to chronic inflammation if left unchecked. Spirulina contains antioxidants, the most noteworthy of which is called phycocyanin.

This powerful antioxidant gives spirulina its signature color and can also balance out excess free radicals in the body. It also blocks the production of inflammatory signaling molecules, preventing some inflammation before it starts.

We just don’t have enough research yet to say for sure that some reported health benefits of spirulina hold true for most people. One example is spirulina’s ability to boost endurance. 

Studies have supported this idea, but they’re extremely small. Spirulina may also be helpful in combating oral cancer, but there has only been one human study and mostly animal studies to back up this supplement’s anti-cancer properties (Kalafati, 2010; Ismail, 2009). 

Multiple animal studies have also shown that spirulina may help control blood sugar, but more research in humans is necessary. One study in humans was done, but it used a small number of participants, and the duration was short (Ou, 2013).

Some researchers also believe that spirulina may improve mental health by boosting the production of serotonin, one of the feel-good hormones, but there’s little science to back up this claim (Demelash, 2018).

And although a 2016 randomized controlled trial looks promising that spirulina may help some people with weight loss and improve their BMI, more work needs to be done in this area (Miczke, 2016).

Spirulina typically comes in either capsule or powder form. Spirulina powder is relatively easy to add to smoothies and drinks.

You may taste it, depending on your dose, but the biggest difference you’ll see is in the blue-green color it lends your drinks. Many supplements suggest a dosage of around 2 g per day, but multiple studies have shown that doses higher than this are generally well-tolerated.

Spirulina supplementation may be a good idea for vegans since it’s a good food source of omega-3 fatty acids and all essential amino acids, which people following this diet may struggle to get through diet alone. But make sure to buy from a high-quality brand you trust since supplements like spirulina are not regulated by the FDA.

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

December 28, 2019

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.