Chlorella: Are There Health Benefits?

Medically Reviewed by Christine Mikstas, RD, LD on November 17, 2022
4 min read

Chlorella is a nutrient-dense freshwater algae. It’s a close cousin to the saltwater-sourced spirulina

Researchers first studied chlorella after World War II as a potential protein option for a growing global population. It has higher levels of vitamins and minerals than spirulina, and is a better source of healthy fats like omega-3s.

But it was never produced on this mass scale due to manufacturing concerns and improved crop efficiency. Still, scientists continue to research its potential as a health-boosting “superfood.” 

Chlorella is available in a dark green powder, capsule, or extract form at many health food stores. You can take it as a supplement, or add it to smoothies, juices, and many sweet or savory recipes.

Three tablets (3.9 g) contains: 

  • Calories: 10
  • Protein: 2 grams
  • Fat: 0
  • Carbohydrates: 1 gram
  • Fiber: 0 grams
  • Sugar: 0 grams

Chlorella is a good source of:

It’s also an excellent source of Bvitamins, including riboflavin (B2), thiamine (B1), and folate (B9). These vitamins help your body convert food to energy, support brain health, and may reduce the risk of some types of cancer.

Chlorella is packed full of nutrients. Depending on its source, it typically contains about 50-60% complete protein with all nine essential amino acids. This makes it a great option for people on a plant-based diet or anyone who needs a protein boost.

In addition, chlorella may offer health benefits including:

Clears Harmful Toxins

Our bodies are exposed to toxins like heavy metals through diet, lifestyle, and environmental factors such as pollution. While considered safe in small amounts, high levels can lead to health issues like illness or organ damage. 

Research has found that chlorella can bind to these heavy metals, flushing them from your system before being absorbed by your body. 

Heart Support

Studies show that the nutrients in chlorella help lower bad (LDL) cholesterol and triglycerides, both of which can cause build-up in your arteries and strain on the heart. 

Chlorella’s fatty acids and minerals like potassium also decrease blood vessel stiffness. This improves the function of blood vessels and lowers blood pressure. Maintaining good cholesterol, blood pressure, and blood vessels reduces your risk of developing heart disease

Reduced Risk of Chronic Illnesses

Chlorella contains violaxanthin — an antioxidant found in leafy greens — that studies show can reduce inflammation. Additional research points to other antioxidants in chlorella, like lycopene, that contribute to this effect.

According to the World Health Organization, chronic inflammation can lead to diabetes, heart disease, gastrointestinal disorders, and arthritis. Inflammation is the leading cause of death in the world. 

Chlorella also contains a wide range of antioxidants such as omega-3s, vitamin C, and carotenoids like beta-carotene and lutein. These nutrients fight cell damage in our bodies and help reduce your risk of diabetes, cognitive disease, heart problems, and cancer

Immune System Support

The antioxidants and other nutrients in chlorella have shown anti-bacterial, anti-viral, and anti-tumor properties. In clinical studies, chlorella increased white blood cell levels, which can stimulate your immune system and help fight infection. 

Respiratory Health

Chlorella’s anti-inflammatory effects may help manage respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD). Studies show it reduces symptoms including coughing, wheezing, or shortness of breath. 

Chlorella may promote better lung function and endurance as well. While more research is needed, one study found it improved lung oxygen levels. This allows for better oxygen delivery around your body and may promote aerobic endurance. 

As a nutritional supplement, chlorella is not well-regulated by agencies like the U.S. Food & Drug Administration (FDA). Because of this, nutritional content can be inconsistent across products sold. Make sure to go with a reliable brand and talk to your doctor before adding chlorella to your diet. 

It’s considered safe for most people, but chlorella may have health risks including:

Stomach Problems

Chlorella may cause nausea, gas, or diarrhea for some people. Consult your doctor before taking it and add it slowly to your diet. 


Some people have an allergy to algae like spirulina and chlorella. While rare, this can lead to breathing problems or anaphylaxis

Pregnancy Concerns

There’s a lack of research to confirm if chlorella is safe for pregnant or breastfeeding women. However, one study concluded that it’s not expected to cause any significant problems for mothers and their infants.

Medication Interactions

Because chlorella may stimulate the immune system, it can reduce the effectiveness of immunosuppressant medications. Due to its high vitamin K content, a nutrient that promotes healthy blood clotting, chlorella can also interact with blood thinners.