Blue-Green Algae - Uses, Side Effects, and More

Who should not use blue-green algae?

Allergies to Ingredients. People who are allergic to any of the following should not take blue-green algae.

• Aphanizomenon flos-aquae (AFA)
• Blue-green algae
• Spirulina (Arthrospira platensis or Arthrospira maxima)
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific blue-green algae products they stock.

What should I know about blue-green algae before using it?

Blue-green algae are used as dietary supplements. They cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep blue-green algae out of the reach of children.

Blue-green algae supplements can vary in their nutritional content and safety depending on the species used, where it was grown, and how it was processed. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

Blue-green algae products, especially those made from AFA, may be contaminated with harmful substances called cyanotoxins, including microcystins. See the Side Effects section for more details. Blue-green algae can absorb heavy metals from the water in which they grow. While studies have found that heavy metal levels in commercially available blue-green algae products generally do not exceed safe limits, the levels can vary between products and batches.

The FDA has not tested blue-green algae products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using blue-green algae?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if blue-green algae is right for you.

In particular, make sure that you discuss any of the following.

Other Medicines and Supplements. Blue-green algae may interact with other supplements and medicines. Before taking blue-green algae, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Autoimmune Disease. Before taking blue-green algae, tell your health care provider if you have an autoimmune condition, such as lupus, rheumatoid arthritis, or multiple sclerosis. Blue-green algae may stimulate the immune system, which could lead to a symptom flare or worsen your condition.

Phenylketonuria (PKU). Blue-green algae are high in protein. People with PKU should be aware that blue-green algae contain phenylalanine (Phe), which is found in protein. If you have PKU, check with your health care provider before use.

Other Current and Past Health Conditions. Tell your health care provider if you have any of the following.

• Bleeding disorders
• Underactive thyroid or other thyroid problems
• Kidney problems
• Liver problems

Pregnancy. It is not known if or how blue-green algae could affect pregnancy or harm a fetus. There is also a risk that blue-green algae products may contain contaminants such as microcystins, which could be harmful. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if blue-green algae pass into breast milk. There is also a risk that blue-green algae products may contain contaminants that could be harmful. Tell your health care provider if you are breastfeeding or plan to breastfeed.