Last updated: August 30, 2021

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Chlorella is a green, single-celled alga consumed in the form of supplements to improve health. It acts as an antioxidant, strengthens the immune system, and reduces both cholesterol and blood pressure. Chlorella is also a source of protein, Omega-3 fats, iron, fiber, and pigments (chlorophyll, lutein, and beta-carotene).

While this alga offers numerous health benefits and can be an excellent dietary supplement for vegans and vegetarians, a lot of misinformation surrounds it. Does it help oxygenate the blood? Can it provide vitamin B12? In our new guide, we will tell you everything there is to know about chlorella.




Key Facts

  • Chlorella is a unicellular alga, which means that it consists of a single cell. This concentrated source of nutrients stands out for its content in proteins, Omega-3 fats, chlorophyll, beta-carotene, and iron. It is an antioxidant, improves the immune response, cares for the sight, prevents anemia, and lowers blood cholesterol.
  • Chlorella must go through a process of disintegration of its cell wall to be assimilated by the body. These supplements come in the form of tablets, extracts, capsules, and powders.
  • You will have to evaluate a series of key criteria before purchasing your chlorella supplement. These include their taste and origin, as well as the potential presence of allergens.

The best Chlorella: Our Picks

While the vast majority of chlorella products out there are safe for consumption, a few may be contaminated with heavy metals from the water where this microalga grows. To help you choose a high-quality supplement, we have selected some of the best products currently available on the market:

Shopping Guide: Everything You Should Know About Chlorella

Eating seaweed, in its natural state or in the form of supplements, has been a dietary trend for a few years now. Although chlorella can be an excellent nutritional product, some of its supposed benefits are false. This has confused many consumers. To solve any doubts you may have, we answered the most frequently asked questions regarding this alga in the section below.

Chlorella smoothie

Chlorella is a concentrated source of nutrients that stands out for its content in proteins, Omega-3 fats, chlorophyll, beta-carotene, and iron.
(Source: Maridav: 36864941/ 123rf.com)

What is chlorella exactly?

This intense green alga is composed of a single eukaryotic cell. It grows in fresh water and is the most abundant source of chlorophyll we know today, this pigment being responsible for its typical color. There are several species of chlorella, but the Chlorella vulgaris is the most studied and used in dietary supplements and cosmetic products (1).

The cell wall of this alga is very resistant and must be broken down for the human body to absorb its nutrients and pigments. This is why chlorella is consumed in the form of supplements – powders, extracts, capsules, and tablets. The microalga is centrifuged and disintegrated to create these products (2, 3).

What nutrients does chlorella provide?

Like most algae, chlorella is full of nutrients, many of which are directly related to the healthy properties of the supplements. Here is the nutritional profile of chlorella powder (1):

  • Proteins: 61 to 64%. The proteins of this microalgae contain all the essential amino acids for the human (4).
  • Fiber: 12 to 13.5%.
  • Carbohydrates: 10 to 14%.
  • Fats: 1.8 to 2.3%, mostly unsaturated, among which we find Omega-3 fats (5).
  • Iron: 80 to 120 mg (per 100 grams of chlorella powder).
  • Vitamin E: 18 mg (per 100 grams of microalgae powder).
  • Carotenoids: Chlorella provides the pigments beta-carotene (provitamin A) and lutein (4).
  • Chlorophyll: Responsible for the green color, this major pigment is found in a concentration ranging from 1 to 4% (4).
  • Other micronutrients: B-complex vitamins (B1, B2, B3, B5, B6, B8, and B9), vitamin K (anti-hemorrhagic), selenium, magnesium, iodine, calcium, and phosphorus.

Chlorella powder

Chlorella must go through a process of disintegration of its cell wall to be assimilated by the body.
(Source: Gojda: 43433922/ 123rf.com)

What are the health benefits of chlorella?

These supplements are considered nutraceutical products. This means that they not only provide nutrients but also have the ability to improve certain aspects of our health, prevent specific diseases, and/or contribute to our overall well-being (4). Here is a list of its health benefits:

  • It has a powerful antioxidant effect due to its content of chlorophyll, beta-carotene, lutein, vitamin E, selenium, and phenolic compounds. These molecules mitigate oxidative damage caused by tobacco, alcohol, sunlight, and environmental pollution, among other agents. Oxidation is associated with numerous cardiac, vascular, renal, and neurodegenerative conditions (6, 7).
  • It reduces fatigue and increases energy levels. Many of chlorella's nutrients are involved in energy metabolism, such as selenium, magnesium, and B-complex vitamins (8).
  • It improves iron intake and prevents iron-deficiency anemia, especially in vegan and vegetarian individuals. Two teaspoons of chlorella powder provide 12 milligrams of iron. However, this iron is non-heme, and our organism cannot assimilate it as well as heme iron found in animal products. Chlorella and vitamin C are combined to improve the absorption of non-heme iron (9).
  • It acts as a hepatoprotector. Several studies have shown promising results when testing the protective effect of chlorella against toxic damage on the liver. This hepatoprotective capacity is similar to that of the medication silymarin and is also linked to its high content of antioxidants (10, 11).
  • It strengthens the immune system. Supplementing with chlorella can contribute to improving the immune response, especially against viruses and cancer cells. This is because it stimulates the activity of a type of lymphocyte called natural killer (NK) (12, 13).
  • It protects eyesight. Chlorella contains an antioxidant pigment (lutein) that can prevent cataract and age-related macular degeneration, which are leading causes of blindness in older adults (14).
  • It reduces cholesterol and blood glucose levels. The hypocholesterolemic properties of chlorella are related to its content of Omega-3 fats and a type of polysaccharide called 1,3-beta-glucan (1). This microalga also lowers blood sugar and improves insulin sensitivity (15).
  • It helps to normalize blood pressure. Chlorella vulgaris has been shown to have an antihypertensive effect; in other words, its daily consumption helps to reduce blood pressure values (16).

What types of chlorella supplements are there?

For the human body to assimilate the nutrients present in this microalga, its cell wall must undergo a process that weakens and disintegrates it. Chlorella supplements come in the form of (3):

  • Powder: Chlorella is centrifuged and micropulverized to a fine powder that dissolves easily in water or other liquids. Its powerful, earthy taste is quite peculiar; many people need some time to get used to it. You are recommended to take 3 to 10 grams per day.
  • Capsules/tablets: These products consist of chlorella powder, either conveyed in a hydroxypropyl methylcellulose package (for capsules) or mixed with silicon dioxide (for tablets). Their taste is much more neutral than that of the powder. Recommended daily intake is 1 to 6 tablets a day.
Chlorella powder Chlorella tablets/capsules
Flavor Strong, bitter, earthy The taste of capsules is almost neutral. The tablets retain the taste of chlorella, but you can barely notice it as you swallow them with water.
Form of consumption Mixed with some liquid (water, milk, vegetable drink, apple juice, shakes). You can also incorporate it into creams, sauces, and baked goods. Simply swallow them with water.
 Recommended daily dose 3 to 10 grams 1 to 6 units

What is the best way to take chlorella supplements?

While there isn't a specific time of day that is most appropriate to take them, we have compiled certain recommendations for their consumption:

  • Capsules and tablets are better tolerated while taken with meals. Some people may experience heartburn when supplementing on an empty stomach.
  • Chlorella powder can be much more pleasant if you mix it in shakes and smoothies with apple juice, kiwi, cocoa, pineapple, ginger, or coconut.
  • If you want to make the most of the iron present in chlorella, you should take the supplements with a source of vitamin C. These include tomato, citrus fruits (orange, lemon, tangerine), strawberries, or kiwi fruit (9).

Chlorella powder & alga

Chlorella is composed of a single eukaryotic cell.
(Source: Neumiler: 99403857/ 123rf.com)

Is chlorella a good source of vitamin B12?

You may notice many nutrition labels for chlorella supplements selling a significant intake of vitamin B12. However, these are actually inactive analogs of the vitamin, which means that they do not perform the function of cyanocobalamin (the active form). The vitamin B12 – or cyanocobalamin – that humans need is found in meat, dairy products, and eggs (17).

Unfortunately, many vegans believe that eating seaweed can help them meet their daily vitamin B12 requirements. The reality is that they are only ingesting a false form, and they expose themselves to megaloblastic anemia and neurological conditions. While blood tests may show healthy vitamin B12 levels, they will suffer from cyanocobalamin deficiency.

Can chlorophyll oxygenate the blood?

No, neither chlorophyll nor any other compound present in food can oxygenate the blood. There is no scientific basis for this claim, and you have no reason to take chlorella for this purpose. Oxygen enters the body in the air we breathe, reaches our lungs, and passes into the blood through our pulmonary alveoli.

Did you know that most chlorella dietary supplements are made from the species called Chlorella vulgaris?

Does chlorella help to remove heavy metals from the body?

This is another widespread affirmation with no scientific evidence to back it up. Although chlorella can act as a sponge that absorbs heavy metals from water and decontaminates it, there is no guarantee that it will capture and remove these elements from the human body. Besides, algae can themselves become contaminated with heavy metals that they absorb from the water (18).

What is the difference between chlorella and spirulina?

These two plants have a similar nutritional profile and share certain health benefits, as they are both antioxidant, energizing, and immunostimulating. However, you should know the differences between chlorella and spirulina (1, 17). You can compare them in the table below:

Chlorella Spirulina
Biological structure Single-celled alga Cyanobacteria
Color Deep green Blue-green
Protein content (in 100 grams) 58 to 61 grams 60 to 66 grams
Iron content (in 100 grams) 76 to 120 milligrams 53 to 66 milligrams

Can I experience side effects from using chlorella?

When consumed in recommended doses, this alga is safe for your health. However, you may experience some adverse effects, especially during the first week. These include stomach pain, vomiting, gas, and allergic reactions. This is why experts recommend starting supplementing with lower doses and work your way up progressively as you get used to these dietary products (1).

Green chlorella powder

Like most algae, chlorella is full of nutrients.
(Source: Chepko: 82271552/ 123rf.com)

Does chlorella have any contraindications?

People who have thyroid conditions such as hypothyroidism or hyperthyroidism must consult their doctor before taking these supplements because iodine may interfere with treatment. In addition, while the consumption of chlorella by pregnant and breastfeeding isn't prohibited, you should ask your obstetrician before supplementing.

Buyer's Guide

You should now be more familiar with the benefits, nutritional profile, and consumption methods of chlorella. However, choosing a supplement is important; you want the best quality to make the most of it while avoiding any risk to your health. This is why we have delved into the main shopping criteria in the section below:

Dosage Form

Tablets and capsules are the easiest way to ingest chlorella since you only need a bit of water to swallow them. Chlorella powder, on the other hand, needs more preparation before consumption. You can dissolve it in water, shakes, creams, or sauces. In fact, some people even mask its taste in their coffee!

Taste

The flavor of chlorella capsules and tablets is practically non-existent, making them ideal for anyone who doesn't tolerate the very peculiar taste of this microalga. The powder is intense, bitter, and earthy. However, many people get used to it over time; others tolerate it better by mixing it with fruits, cocoa, ginger, or coconut.

Place of Production

North American and European countries have the strictest legislation regarding the safety of nutritional supplements. This is fundamental for chlorella products, as the alga can be contaminated with heavy metals. When you purchase your supplements, try and stick to those processed and packaged in North America or Europe. The raw material is often grown in other places, such as China, but this shouldn't be a concern.

Organic Certification

Chlorella must be organic. When synthetic chemicals are used to stimulate its growth, these compounds can remain in the alga and enter the human body. Besides, this type of farming harms the environment.

Did you know that a doctor will need to ask for a methylmalonic acid blood test to detect whether or not a vegan has a vitamin B12 deficiency? The presence of chlorella analogs makes the vitamin B12 values in standard blood samples unreliable.

Presence of Allergens

Chlorella is naturally free of gluten and other allergens, but that doesn't mean that the supplements cannot contain them. Contamination during processing is a common problem in these dietary products. Anyone suffering from a food allergy or intolerance should carefully read the nutrition label to check that they can safely consume the supplement.

Summary

Chlorella is a green single-celled alga that can enhance the nutritional quality of your diet and improve certain aspects of health. It is a source of proteins of high biological value and iron, which is why chlorella is an excellent food supplement for vegan and vegetarian individuals.

Chlorella comes in the form of powder, capsules, and tablets. The cell wall of this microalga is disintegrated to help the human body better absorb its components. Chlorella is rich in antioxidants, protects the health of the liver and eyesight, improves immunity, and lowers cholesterol and blood glucose levels.

Did you enjoy our guide on this wonderful alga? Feel free to give us your opinion by leaving a comment below, and don't forget to share this article on your social media!

(Featured Image Source: Schweitzer: 64035399/ 123rf.com)

References (19)

1. Rani K, Sandal N, Sahoo PK. A comprehensive review on chlorella- its composition, health benefits, market and regulatory scenario [Internet]. The Pharma Innovation Journal. 2018.
Source

2. Görs M, Schumann R, Hepperle D, Karsten U. Quality analysis of commercial Chlorella products used as dietary supplement in human nutrition [Internet]. Journal of Applied Phycology. 2009.
Source

3. Masojídek J, Torzillo G. Mass Cultivation of Freshwater Microalgae [Internet]. Encyclopedia of Ecology. 2014.
Source

4. Paniagua-Michel J. Microalgal Nutraceuticals. En Handbook of Marine Microalgae [Internet]. 2015.
Source

5. Rezende Freitas H. Chlorella vulgaris as a Source of Essential Fatty Acids and Micronutrients: A Brief Commentary [Internet]. 2017
Source

6. Miranda M, Mancini J. Antioxidant activity of the microalga Chlorella vulgaris cultured on special conditions [Internet]. 2001.
Source

7. Lee SH et al. Six-week supplementation with Chlorella has favorable impact on antioxidant status in Korean male smokers [Internet]. 2010.
Source

8. Okada H, Yoshida N, Kakuma T, Toyomasu K. Effect of Chlorella Ingestion on Oxidative Stress and Fatigue Symptoms in Healthy Men [Internet]. 2018.
Source

9. Lynch S, Cook J. Interaction of vitamin C and iron [Internet]. 1980.
Source

10. Peng H, Chu Y, Chen S, Chou S. Hepatoprotection of chlorella against carbon tetrachloride-induced oxidative damage in rats [Internet]. 2009.
Source

11. Cai X, Wang S, Yang Q. Antioxidant and hepatoprotective effects of pigment-protein complex from Chlorella vulgaris on carbon tetrachloride-induced liver damage in vivo [Internet]. 2015.
Source

12. Azocar J, Díaz A. Efficacy and safety of Chlorella supplementation in adults with chronic hepatitis C virus infection [Internet]. 2013.
Source

13. Kwak J et al. Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of Natural Killercell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial) [Internet]. Nutrition Journal. 2012.
Source

14. Shibata S, Nishihara T, Natori Y, Tomisaka K. Antioxidant and Anti-Cataract Effects of Chlorella on Rats with Streptozotocin-Induced Diabetes [Internet]. Journal of Nutritional Science and Vitaminology. 2003.
Source

15. Jeong H, Kwon H, Kim M. Hypoglycemic effect of Chlorella vulgaris intake in type 2 diabetic Goto-Kakizaki and normal Wistar rats [Internet]. 2009.
Source

16. Suetsuna K, Chen J. Identification of Antihypertensive Peptides from Peptic Digest of Two Microalgae, Chlorella vulgaris and Spirulina platensis [Internet]. Marine Biotechnology. 2001.
Source

17. Kamudha A et al. Methylcobalamin – A form of vitamin B12 identified and characterised in Chlorella vulgaris [Internet]. 2015.
Source

18. Kumar R, Frankilin J, Raj S. Accumulation of heavy metals (Cu, Cr, Pb and Cd) in freshwater micro algae (Chlorella sp.) [Internet]. 2013.
Source

19. Karkos P, Leong S, Assimakopoulos D. Spirulina in Clinical Practice: Evidence-Based Human Applications [Internet]. 2011.
Source

Medical Article
Rani K, Sandal N, Sahoo PK. A comprehensive review on chlorella- its composition, health benefits, market and regulatory scenario [Internet]. The Pharma Innovation Journal. 2018.
Go to source
Scientific article
Görs M, Schumann R, Hepperle D, Karsten U. Quality analysis of commercial Chlorella products used as dietary supplement in human nutrition [Internet]. Journal of Applied Phycology. 2009.
Go to source
Scientific article
Masojídek J, Torzillo G. Mass Cultivation of Freshwater Microalgae [Internet]. Encyclopedia of Ecology. 2014.
Go to source
Scientific article
Paniagua-Michel J. Microalgal Nutraceuticals. En Handbook of Marine Microalgae [Internet]. 2015.
Go to source
Scientific article
Rezende Freitas H. Chlorella vulgaris as a Source of Essential Fatty Acids and Micronutrients: A Brief Commentary [Internet]. 2017
Go to source
Scientific article
Miranda M, Mancini J. Antioxidant activity of the microalga Chlorella vulgaris cultured on special conditions [Internet]. 2001.
Go to source
Scientific article
Lee SH et al. Six-week supplementation with Chlorella has favorable impact on antioxidant status in Korean male smokers [Internet]. 2010.
Go to source
Scientific article
Okada H, Yoshida N, Kakuma T, Toyomasu K. Effect of Chlorella Ingestion on Oxidative Stress and Fatigue Symptoms in Healthy Men [Internet]. 2018.
Go to source
Medical Article
Lynch S, Cook J. Interaction of vitamin C and iron [Internet]. 1980.
Go to source
Medical Article
Peng H, Chu Y, Chen S, Chou S. Hepatoprotection of chlorella against carbon tetrachloride-induced oxidative damage in rats [Internet]. 2009.
Go to source
Informative article
Cai X, Wang S, Yang Q. Antioxidant and hepatoprotective effects of pigment-protein complex from Chlorella vulgaris on carbon tetrachloride-induced liver damage in vivo [Internet]. 2015.
Go to source
Scientific article
Azocar J, Díaz A. Efficacy and safety of Chlorella supplementation in adults with chronic hepatitis C virus infection [Internet]. 2013.
Go to source
Scientific article
Kwak J et al. Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of Natural Killercell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial) [Internet]. Nutrition Journal. 2012.
Go to source
Medical Article
Shibata S, Nishihara T, Natori Y, Tomisaka K. Antioxidant and Anti-Cataract Effects of Chlorella on Rats with Streptozotocin-Induced Diabetes [Internet]. Journal of Nutritional Science and Vitaminology. 2003.
Go to source
Scientific article
Jeong H, Kwon H, Kim M. Hypoglycemic effect of Chlorella vulgaris intake in type 2 diabetic Goto-Kakizaki and normal Wistar rats [Internet]. 2009.
Go to source
Medical Article
Suetsuna K, Chen J. Identification of Antihypertensive Peptides from Peptic Digest of Two Microalgae, Chlorella vulgaris and Spirulina platensis [Internet]. Marine Biotechnology. 2001.
Go to source
Scientific article
Kamudha A et al. Methylcobalamin – A form of vitamin B12 identified and characterised in Chlorella vulgaris [Internet]. 2015.
Go to source
Medical Article
Kumar R, Frankilin J, Raj S. Accumulation of heavy metals (Cu, Cr, Pb and Cd) in freshwater micro algae (Chlorella sp.) [Internet]. 2013.
Go to source
Medical Article
Karkos P, Leong S, Assimakopoulos D. Spirulina in Clinical Practice: Evidence-Based Human Applications [Internet]. 2011.
Go to source
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