Blue – Green Algae


Blue-green algae refers to several species of bacteria that produce blue-green colored pigments. They grow in salt water and some large fresh water lakes. They have been used for food for several centuries in Mexico and some African countries. They have been sold as a supplement in the US since the late 1970s.

Blue-green algae products are sometimes used by mouth as a protein supplement and for treating high blood pressure. Blue-green algae products are also used by mouth for many other conditions, but there is no good scientific evidence to support these uses.

Some blue-green algae products are grown under controlled conditions. Others are grown in a natural setting, where they are more likely to be contaminated by bacteria, liver poisons (microcystins) produced by certain bacteria, and heavy metals. Choose only products that have been tested and found to be free of these contaminants.

You may have been told that blue-green algae are an excellent source of protein. But, in reality, blue-green algae are no better than meat or milk as a protein source and cost about 30 times as much per gram.


Is a Form of:


Primary Functions:

High blood pressure

Also Known As:

AFA, Algae, Algas Verdiazul, Algues Bleu-Vert, Algues Bleu-Vert du Lac Klamath, Anabaena

How Does It Work?

Blue-green algae have a high protein, iron, and other mineral content which is absorbed when taken orally. Blue-green algae are being researched for their potential effects on the immune system, swelling (inflammation), and viral infections.


  • High blood pressure.Taking blue-green algae by mouth seems to reduce blood pressure in some people with high blood pressure.

Recommended Dosing

The following doses have been studied in scientific research:


  • For high blood pressure: 2-4.5 grams of blue-green algae per day has been used.

Blue – Green Algae Supplements Frequently Asked Questions

Are blue green algae supplements safe?

When taken by mouth: Blue-green algae products that are free of contaminants, such as liver-damaging substances called microcystins, toxic metals, and harmful bacteria, are POSSIBLY SAFE for most people when used short-term. Doses up to 19 grams per day have been used safely for up to 2 months.

Is Spirulina the same as blue green algae?

Spirulina is an organism that grows in both fresh and salt water. It is a type of cyanobacteria, which is a family of single-celled microbes that are often referred to as blue-green algae.

What does Blue Green Algae do to humans?

Exposure to high levels of blue-green algae and their toxins can cause diarrhea, nausea or vomiting; skin, eye or throat irritation; and allergic reactions or breathing difficulties.

How do you treat Blue Green Algae?

Treatment of a surface water that is experiencing a blue-green algae bloom with an herbicide or algaecide may kill the blue-green algae, but any toxin(s) contained in the cells will be released at once, resulting in a slug of toxin(s) in the water.

What is blue algae good for?

Some people use blue-green algae for treating precancerous growths inside the mouth, twitching of the eyelids, boosting the immune system, improving memory, increasing energy and metabolism, improving exercise performance, lowering cholesterol, preventing heart disease, healing wounds, and improving digestion and bowel ..

What happens if you swim in water with blue green algae?

If you have contact (e.g., swimming, boating) with water containing blue green algae, it can cause: skin irritation and rash. sore throat. sore, red eyes.

How long does it take for blue green algae to make your dog sick?

Signs/Symptoms Your Dog May Have Ingested Blue-Green Algae:

Symptoms, which usually arise anywhere from 15 minutes to several days after exposure may include: Diarrhea or vomiting. Drooling.

Does blue green algae go away?

A: Blue green algae, or cyanobacteria, can multiply quickly in lakes with high nutrient levels, particularly when the water is warm and the weather is calm. ... A blue green algae bloom can also lie below the surface of the water. Blooms can spontaneously disappear or move to different parts of a pond or lake.

Does chlorine kill Blue Green Algae?

Green Algae: Green algae usually floats, but sometimes it attaches to walls. ... Blue-green algae are also chlorine resistant. This algae type forms a layered structure where the first layer can be killed by chlorine, but the bottom layers are protected.

Can fish survive in blue green algae?

Are fish caught from these waters safe to eat? The toxins produced by freshwater blue-green algae do not appear to bioaccumulate in fish and other edible aquatic life in lakes and rivers to the degree that they can in some seafood. Toxic results from consumption of freshwater animals have not been documented.

What foods contain blue green algae?

The dietary supplement industry touts the positive effect of algae products. The majority of commercialised products are based on blue-green algae such as Spirulina and Aphanizomenon flos-aquae or green algae such as Chlorella. Algae food supplement manufacturers often advertise their products as “blue-green algae”.

What are the health risks of blue green algae?

Exposure to high levels of blue-green algae and their toxins can cause diarrhea, nausea or vomiting; skin, eye or throat irritation; and allergic reactions or breathing difficulties.

What causes blue green algae?

Causes. One key factor contributing to the growth of blue-green algae is the amount of available nutrients such as phosphorus and nitrogen. Blue-green algal blooms can be caused by agricultural and stormwater runoff as well as leaching from septic systems.

How can you tell blue algae from regular algae?

There are, however, warning signs: The "blooms" tend to clump together near the surface water and could be anywhere from bright green to brownish. In general, if parts of the water appear to be thick and mucky, there's a chance it's because of blue-green algae.

How can you tell blue algae from regular algae?

There are, however, warning signs: The "blooms" tend to clump together near the surface water and could be anywhere from bright green to brownish. In general, if parts of the water appear to be thick and mucky, there's a chance it's because of blue-green algae.

How long do symptoms of blue green algae last?

How long after exposure do symptoms appear? Gastrointestinal effects may occur with 3-5 hours. Symptoms are generally mild; but can be severe and usually last 1-2 days.

Is green algae harmful in pool?

Algae is not harmful to swimmers per se, but pools with algae may also be a safe harbor for pathogens like E-coli bacteria. ... Algae create a chlorine demand in the water for itself, consuming chlorine that should be working on other contaminants. As it expels carbon dioxide, the pH level of pool water can rise.

How long will an algae bloom last?

How long do algal blooms last? Harmful algal blooms will remain as long as there are favourable conditions, including warmth, sunlight and low flow rates. Blooms can last from weeks to months and it is difficult to predict when they will clear.

What are the symptoms of blue green algae?

Others affect the liver and it takes days before symptoms appear. Symptoms from drinking water with cyanobacterial toxins include: headaches, nausea, fever, sore throat, dizziness, stomach cramps, diarrhea, abdominal pain, vomiting, muscle aches, mouth ulcers and blistering of the lips.

Does baking soda kill algae?

Bicarbonate, the active ingredient in the baking soda, is an effective spot treatment to help to kill the algae and loosen it from the wall. ... But with enough scrubbing, you can banish the black algae for good.

What is green algae good for?

Spirulina is a type of cyanobacteria — often referred to as blue-green algae — that is incredibly healthy. It may improve your levels of blood lipids, suppress oxidation, reduce blood pressure and lower blood sugar.

Clinical Studies