Danger of Spirulina

Spirulina is often touted as a miracle superfood, a powerhouse of nutrition, yet the danger of spirulina reactions, overdose or heavy metal poisoning exists.

Blue Green Algae for Health

Spirulina, along with chlorella and other blue green algae types are often promoted as the latest superfood. People credit spirulina for curing serious diseases, helping children with autism, and providing relief from vitamin deficiencies.

Spirulina contains an amazing amount of nutrition packed into each tiny single celled organism. Spirulina contains a huge amount of beta carotene, vitamin A, essential fatty acids, and B vitamins. Yet despite all these healthy goodies packed into each tablet or teaspoon of powder, the spirulina dangers are real,

Danger of Spirulina

There are three known categories dangers related to spirulina: reactions, diarrhea and stomach upset, and heavy metal poisoning.

Reactions and Allergies

People can be allergic to almost anything on the planet. An allergen is simply a substance that triggers a person's immune system to go on the defense. When the allergen enters the body, the immune system reacts to the particle as if it were a deadly invader such as a virus or bacteria. Foods, medications, animal dander, plant pollen and many other substances can cause reactions and allergies, including spirulina.

Some people have mild reactions to spirulina. These allergic reactions may include a rash or skin discomfort. Rarely, severe reactions may occur. These include hives, difficult breathing, and asthma-like symptoms. If you've taken spirulina and have trouble breathing, you may be severely allergic and need medical attention. Stop taking spirulina and see a physician immediately. Usually mild allergy symptoms go away on their own after people stop taking spirulina.

Diarrhea and Stomach Upset

A most unpleasant reaction to spirulina is the danger of stomach upset, specifically, diarrhea. Usually this happens when people take too much spirulina. Always follow label and package directions carefully, and never exceed the recommended dose. Each product is manufactured differently, so one brand's dose may be different from another. When changing product brands, reread the label to ensure you're taking spirulina supplements according to package directions.

If stomach cramps and diarrhea occur, stop taking spirulina. Symptoms should pass within a short period of time once you stop taking spirulina supplements.

Heavy Metal Poisoning

By far the most frequently cited danger of spirulina is heavy metal toxicity or poisoning. How does a blue green algae poison someone? The answer lies in where the algae was grown and in how it is harvested.Spirulina is an algae, and algae grows on lakes, ponds and in man-made ponds. If the water it's grown in contains heavy metals such as mercury or lead, the little spirulina algae will absorb the metals. Then when they are harvested and dried into a supplement, the metals remain inside the supplement.

Fortunately, heavy metal toxicity from spirulina is very rare. When purchasing supplements, quality brands do make a difference. Many name brands have testing laboratories and provide test results to the general public. If you're concerned about heavy metals infesting your spirulina supplement, contact the manufacturer and ask if the supplement has been tested. Ask for a copy of the test results. If you follow the label directions and take only as much as is recommended, you should avoid contamination from heavy metals.

Spirulina Precautions

Spirulina is generally a safe supplement for the majority of people. Yes, allergies and reactions can occur, but allergies occur with common foods, too, such as dairy products or peanuts. Heavy metal poisoning from spirulina is uncommon. To be on the safe side, pregnant and nursing women should avoid taking spirulina supplements, since unborn babies and infants are at high risk for brain and nervous system damage if exposed to heavy metal toxins. Never harvest spirulina or algae in the wild. It may be contaminated. Without the proper testing equipment, you have no way of knowing if the algae has picked up bacteria or metal contaminants. Just because a body of water looks clean doesn't mean it is free from heavy metal poisons.


Spirulina can be a great dietary supplement. Use common sense, discontinue use if any side effects occur, and choose high quality supplements to be safe.

Danger of Spirulina