Overview

Blue-green algae are a group of bacteria. They can be used as a source of protein, but contain no more protein than meat or milk.

Blue-green algae produce blue-green colored pigments and are high in protein, iron, and other minerals. They grow in saltwater and some large freshwater lakes. They have been used for food for several centuries in Mexico and some African countries. In the US, they've been sold in supplements since the late 1970s.

People use blue-green algae for treating high blood pressure and as a protein supplement. It's also used for high levels of cholesterol or other fats (lipids) in the blood, diabetes, obesity, and many other conditions. But there is no good scientific evidence to support these other uses.

Some blue-green algae products are grown under controlled conditions. Others are grown in a natural setting, where they're more likely to be contaminated. Only use products that have been tested and are free of contaminants such as heavy metals, liver toxins called microcystins, and harmful bacteria. Don't confuse blue-green algae with other algaes, like Ascophyllum nodosum, Ecklonia cava, Fucus Vesiculosis, or Laminaria.



Uses & Effectiveness

Possibly Effective for

There is interest in using blue-green algae for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: Blue-green algae products that are free of contaminants are possibly safe for most people when used short-term. Doses up to 19 grams daily have been used safely for up to 2 months. Lower doses of 10 grams daily have been used safely for up to 6 months. Side effects are typically mild and may include nausea, vomiting, diarrhea, headache, and dizziness.

But blue-green algae products that are contaminated are possibly unsafe. Contaminated blue-green algae can cause liver damage, vomiting, weakness, rapid heartbeat, shock, and death. Don't use any blue-green algae product that hasn't been tested and found to be free of microcystins and other contaminants.

Special Precautions and Warnings

When taken by mouth: Blue-green algae products that are free of contaminants are possibly safe for most people when used short-term. Doses up to 19 grams daily have been used safely for up to 2 months. Lower doses of 10 grams daily have been used safely for up to 6 months. Side effects are typically mild and may include nausea, vomiting, diarrhea, headache, and dizziness.

But blue-green algae products that are contaminated are possibly unsafe. Contaminated blue-green algae can cause liver damage, vomiting, weakness, rapid heartbeat, shock, and death. Don't use any blue-green algae product that hasn't been tested and found to be free of microcystins and other contaminants.

Pregnancy and breast-feeding: There isn't enough information available to know if it is safe to use blue-green algae when pregnant or breast-feeding. Contaminated blue-green algae products contain harmful toxins that might be transferred to an infant during pregnancy or through breast milk. Stay on the safe side and avoid use.

Children: Blue-green algae are possibly unsafe for children. Children are more sensitive to contaminated blue-green algae products than adults.

Auto-immune diseases such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), pemphigus vulgaris (a skin condition), and others: Blue-green algae might cause the immune system to become more active, and this could increase the symptoms of auto-immune diseases. If you have one of these conditions, it's best to avoid using blue-green algae.

Surgery: Blue-green algae might lower blood sugar levels. There is some concern that it might interfere with blood sugar control during and after surgery. Stop using blue-green algae at least 2 weeks before a scheduled surgery.

Interactions

    Moderate Interaction

    Be cautious with this combination

  • Medications that decrease the immune system (Immunosuppressants) interacts with Blue-Green Algae

    Blue-green algae can increase the activity of the immune system. Some medications, such as those used after a transplant, decrease the activity of the immune system. Taking blue-green algae along with these medications might decrease the effects of these medications.

  • Medications for diabetes (Antidiabetes drugs) interacts with Blue-Green Algae

    Blue-green algae might lower blood sugar levels. Taking blue-green algae along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

  • Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs) interacts with Blue-Green Algae

    Blue-green algae might slow blood clotting. Taking blue-green algae along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Dosing

Blue-green algae has most often been used by adults in doses of 1-10 grams by mouth daily for up to 6 months. Only use products that have been tested and are free of contaminants such as heavy metals, liver toxins called microcystins, and harmful bacteria. Speak with a healthcare provider to find out what product and dose might be best for a specific condition.
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CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is licensed from Therapeutic Research Center, LLC. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
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