Spirulina is a nutrition-dense food source. It’s sold in several forms, including powder, flakes, and pills. It can be used as an ingredient in every day recipes or taken orally as a nutritional supplement.

Spirulina’s health benefits haven’t been scientifically proven. It may have a positive impact on many health concerns, including malnutrition, cancer, and diabetes. Whether you want to add spirulina to your diet for better nutrition or because of a diagnosis you’ve received, here’s what you need to know.

Spirulina is a type of cyanobacteria, or blue-green algae. It grows wild in warm ocean waters. It’s also found in subtropical and tropical lakes. Microscopic in size, the one-celled organisms grow in spirals and clump together. This makes them easy to harvest. Spirulina is also grown commercially in controlled environments, such as laboratories.

The U.S. Food and Drug Administration (FDA) has approved its use as a food coloring and its presence in candy and gum. It’s often found in dietary supplements, which don’t require FDA approval to be sold for nutritional purposes.

Spirulina is a considered a superfood because it contains large amounts of nutrients, including:

  • vitamins
  • minerals
  • iron
  • protein
  • calcium

It’s also high in antioxidants, which may protect cells from damage caused by free radicals. Antioxidants like those found in spirulina may provide some protection from multiple diseases, such as cancer, HIV, and Alzheimer’s disease.

A review article in the Journal of Marine Biology suggests that spirulina may be effective against tumors. It may also have antiviral and antifungal properties.

Other research shows that spirulina may help control blood glucose in people with type 2 diabetes. It may also help reduce cholesterol and triglycerides.

Spirulina growing in the wild may become contaminated with toxins, called microcystins. Microcystins can cause severe liver damage. The algae also absorbs toxic pollutants and radioactive heavy metals found in water.

It’s important to know where the spirulina you purchase comes from. You should only buy reputable brands you trust. Most spirulina sold in the U.S. is safely grown in laboratories.

Spirulina isn’t for everyone. You shouldn’t consume spirulina if:

  • you’re allergic to seafood, seaweed, or other sea plants. You may also be allergic to spirulina. Check with your doctor.
  • you have a thyroid condition. Spirulina contains iodine, which can sometimes be harmful in high doses to people with hyperparathyroidism.
  • you have any type of autoimmune disorder, including lupus, rheumatoid arthritis and multiple sclerosis. Spirulina may stimulate the immune system, and negatively affect these conditions.
  • you have a rare, inherited condition called phenylketonuria (PKU). Spirulina contains large amounts of amino acids, such as phenylalanine. Phenylalanine is hard for people with PKU to metabolize.

If you’re pregnant, considering becoming pregnant, or currently breast-feeding, you should check with your doctor before taking spirulina.

Spirulina may interfere with medications you’re taking. If you take any type of medication, let your doctor know you’re considering adding spirulina to your diet.

You may decide to take spirulina as a supplement. If so, make sure to follow these steps:

  • When taken in pill or capsule form, the recommended dose is 2,000-3,000 mg daily. It’s usually taken several times a day, rather than in one dose.
  • If you’re new to spirulina, you may be advised to build up your dose slowly. This can help you avoid side effects. Temporary side effects can include sweating, facial flushing, and headache.
  • Spirulina also acts like a stimulant in some people, so you may be recommended to avoid using it at night.

In food:

  • Spirulina can be used as an ingredient in everything from stews to salad. You experiment with it in recipes you already make, such as chicken soup or scrambled eggs.
  • It has a highly digestible form of protein that doesn’t require cooking for maximum absorption. Serving it in a cold dish is just as beneficial as in a hot dish.
  • It has a seaweed taste that may take some getting used to. Many people enjoy it spooned and blended into smoothies.

Check out: Healthy smoothie recipes »

Spirulina is an ancient food source. It may even have been used by the Aztecs during the 16th century. Despite its longevity, there isn’t a large body of scientific evidence to back up claims about its health benefits. Superfood or not, consider checking in with your doctor about spirulina before you start using it, either as an ingredient in recipes or as a supplement.