Comparison Between Spirulina & Chlorella


Chlorella and spirulina both are touted as protein-rich superfoods that are rich in a variety of nutrients. Supplementing with either of these algae may boost the immune system and help people ward off a variety of health conditions. However, not enough clinical research exists to definitively state whether purported health benefits exist.

Chlorella Identification

Chlorella pyrenoidosa is a blue-green, single-cell algae that is used as a supplement. It is rich in protein, and in fact consists of about 58 percent of the recommended daily value of protein, as well as vitamins and minerals. These include vitamin C, B vitamins, vitamin E, potassium, zinc, iron, magnesium, lutein, some 18 amino acids and chlorophyll, according to “Prescription for Nutritional Healing,” by Phyllis A. Balch, CNC, 2003. Chlorella also has an abundance of beta-carotene, with 4,559 IU in a 3g serving, according to the company Sun Chlorella USA.

Spirulina Identification

Spirulina also is a nutrient rich blue-green algae that people use as a supplement. It has up to 70 percent protein. It also is a strong source of beta-carotene, containing more than carrots do, as well as B vitamins, vitamin E, phycocyanin, chlorophyll and numerous minerals, according to the National Institutes of Health (NIH).


Spirulina has been used by people since ancient times as a nutrient source. It is purported to have a variety of medical uses, including as a lipid-lowering agent and a weight-loss aid, and antioxidant and antiviral properties, according to the NIH. Chlorella was discovered in 1890 by a Dutch microbiologist. Chlorella also is thought to benefit people who suffer a host of conditions thanks to its antioxidant and nutritional properties.


The NIH reports that preliminary data from studies on animals demonstrates that spirulina is effective for some conditions. It also appears to be safe to use. NIH cautions, however, that human evidence is lacking and says that no recommendation can be made against or for using spirulina for any medical condition. Studies are being conducted on its possible benefits to people who suffer nasal allergies, arsenic poisoning, eye disorders, diabetes, high cholesterol and malnutrition.

There is not enough scientific evidence to officially recommend for or against chlorella, either. Studies are examining chlorella for use in treating ulcerative colitis, fibromyalgia and hypertension, according to the “Journal Alternative Therapies in Health and Medicine.”


Most recently chlorella has been studied for use in pregnant women to improve anemia as well as pregnancy-induced hypertension and in smokers as an antioxidant that can help combat some of the negative impacts of smoking. It’s also being examined for its effect on insulin resistance, age-related oxidative stress and as a protector of the liver that some say is just as potent as milk thistle, the number one natural remedy for supporting liver health, according to

Most recent studies on spirulina have focused on its potential to improve stamina during exercise and possible health improvements on those who have diabetes. Supplementation with both of these algae has been looked to as possible methods of mitigating exposure to heavy metals.

About this Author

Linda Tarr Kent is a reporter and editor with 20 years’ experience at Gannett Company Inc., The McClatchy Company, Sound Publishing Inc., Mach Publishing, MomFit The Movement and other companies. Her area of expertise is health and fitness. She is a Bosu fitness and stand-up paddle surfing instructor. Tarr Kent holds a bachelor’s degree in journalism from Washington State University.