Spirulina is a blue-green-colored algae that is also considered one of the greatest superfoods. As a result, it is used in many supplements. The reason behind this is that spirulina is rich in vitamins and minerals with 60% comprising of protein. 

If that wasn’t enough, spirulina contains several antioxidants and polyunsaturated fats. Due to all these nutritional elements, spirulina acts as a great immunity booster and is used by many people for its antioxidant and anti-inflammatory properties. 

Side-Effects And Potential Dangers Of Spirulina

There are several health benefits of spirulina, but it can also pose dangers to some people, especially those with certain medical conditions. Therefore, it is best to ask your doctor if you can use any foods and supplements with spirulina. 

Risk Of Contamination

The primary downside of spirulina is that it may be contaminated with toxins if the algae is grown in polluted water. Polluted water may contain viruses, heavy metals, bacteria, as well as microcystins. Microcystins could have adverse effects on the liver. 

Moreover, spirulina could also cause heavy metal contamination among the people who consume it. This could result in serious organ damage. However, you would have to consume a large dosage of spirulina to be exposed to this risk. 

Slower Blood Clotting

Spirulina could act as an anticoagulant, which means it can thin your blood and thereby increase the time it takes for your blood to clot. Due to slower blood clotting, bruises and wounds would take a longer time to heal. 

This risk could result in serious damage for people who are already taking blood thinners like certain blood pressure medication. If you have a bleeding disorder, you should avoid the use of spirulina as it may slowdown the blood clotting process, making you more susceptible to excessive bleeding. 

May Aggravate Auto-Immune Conditions

Spirulina acts as an immune system booster. Due to this, it may negatively impact autoimmune conditions like multiple sclerosis and lupus. In auto-immune disorders, the immune system starts to attack the body, which can be exacerbated by spirulina. 

If you have an auto-immune condition, you should avoid the use of spirulina. It might have certain undeniable benefits, but in this case, its action can prove counterproductive. 

Trigger Allergic Reactions

Just like most other things, spirulina can have a variety of allergic reactions, which may be more severe for some people. In most cases, spirulina will only pose mild discomfort or cause minor allergic reactions like a skin rash, temporary discomfort, insomnia, or nausea. In more serious and rare cases, allergic reactions from spirulina may prove to be fatal but generally are considered safe. 


Spirulina has its share of health benefits and certain potential dangers, especially in people who are dealing with specific health conditions. It may slow down blood clotting, aggravate auto-immune conditions, cause toxicity, and trigger a number of allergic reactions. 

In case of such an event, the best course of action would be to consult a physician and let them decide if the use of spirulina is okay for you. In normal circumstances, most people who use spirulina do not report any side effects or adverse reactions.