Chlorella

Medically Reviewed by Melinda Ratini, MS, DO on July 31, 2024
2 min read

Chlorella is a type of freshwater seaweed (green algae). It contains protein, iron, vitamins B and C, and other antioxidants.

It may contain substances that fight bacteria, fungi, tumors, and viruses.

Chlorella may help your immune system work better. Some evidence suggests chlorella may:

  • Help people with certain tumors better tolerate chemotherapy and radiation
  • Raise white blood cell count in people with HIV or cancer, which helps your body fight infections
  • Protect against cell damage from radiation and toxic metals, such as lead

Chlorella has been used to try to treat gastrointestinal disorders, including:

  • Constipation
  • Diverticulitis
  • Inflammatory bowel disease (Crohn's and ulcerative colitis)
  • Stomach ulcers

Chlorella has also been used to try to treat or prevent:

  • Asthma attacks
  • Bad breath
  • Fibromyalgia
  • High cholesterol
  • High blood pressure
  • Low B-12 levels
  • Premenstrual syndrome (PMS)
  • Trichomoniasis (a sexually transmitted infection)
  • White patches on the genitals called vulvar leukoplakia

Some people also take chlorella to try to:

  • Boost energy levels
  • Detox the body
  • Improve mental function

More research is needed to determine the effectiveness of chlorella to treat any of these conditions.

Chlorella is used as a food additive in Japan.

Studies suggest that chlorella may be safe when taken by mouth for a short amount of time, up to two months.

Side effects of chlorella include:

Allergic reactions have been reported in some people taking chlorella. These reactions have included severe breathing problems and a life-threatening allergic reaction called anaphylaxis.

There isn't enough research to know if chlorella is safe for women who are pregnant or breastfeeding.

Chlorella may make it harder for warfarin and other blood-thinning drugs to work.

Some chlorella supplements may contain iodine, so people with an allergy to iodine should avoid them.

Always tell your doctor about any supplements you are taking, including natural ones and those bought without a prescription. That way, your doctor can check on any potential side effects or interactions with any medications.

Supplements are not regulated by the FDA in the same way that drugs are. The FDA does not review these supplements for safety or efficacy before they hit the market.