Chlorella Superfood: Scientifically Proven Benefits

Closeup of chlorella algae powder with wooden scoop

What’s over 2 billion years old but helps keep you feeling young and healthy? Chlorella, that’s what! As one of the most popular algae dietary supplements on the market today, chlorella products are a staple of the health and wellness industry. But if you’re unfamiliar with algae as health food, you may be wondering what this so-called chlorella superfood is all about. No worries. That’s where we come in! So come with us as we uncover all you need to know about chlorella—superfood extraordinaire.

Chlorella vs. Spirulina

Chlorella is often lumped together with its cousin spirulina. And while the two do share some similarities, they also have a number of differences.

For example, spirulina is a multicellular blue-green algae, while chlorella is a single-celled green algae. This means chlorella is much smaller than spirulina and contains slightly different phytochemicals. Chlorella is also a rapidly growing type of freshwater algae and can quadruple its size over the course of a single day.

What’s more, spirulina can be consumed as soon as it’s harvested, but chlorella has a hard cell wall that must be physically cracked before it can be digested.

However, like spirulina, chlorella is a great source of chlorophyll. In fact, it’s an even better source, as it contains almost twice the amount of chlorophyll as spirulina does. This high chlorophyll content also makes chlorella an effective chelator of heavy metals—a property that can act as a double-edged sword if chlorella is grown in unsafe conditions, as it will absorb the heavy metals present in its environment.

Types of Chlorella

While there are many different species of chlorella, the two that have been most widely studied are Chlorella vulgaris and Chlorella pyrenoidosa. Interestingly, studies have found that Chlorella pyrenoidosa actually has a higher concentration of certain vitamins and amino acids. Chlorella pyrenoidosa also contains more chlorella growth factor (CGF) than Chlorella vulgaris.

CGF is composed of the nucleic acids RNA and DNA and isn’t found in other microalgae. This unique substance, which is produced during photosynthesis within the nucleus of chlorella cells, is also the reason behind chlorella’s remarkable ability to grow so quickly.

Fun Fact: Following World War II, when fears of a global population boom were growing, scientists looked to chlorella as a possible alternative to more energy-intensive meat production. However, the initial interest in chlorella as the world’s next “most important agricultural crop” waned with the advent of more efficient agricultural practices.

Chlorella Superfood with Super Health Benefits

Even a casual glance at the nutrients in chlorella superfood gives you an instant impression of why this green alga is so good for you. For example, just 1 ounce of chlorella contains:

  • 33% of the RDA of protein
  • 287% of the RDA of vitamin A
  • 32% of the RDA of thiamine
  • 71% of the RDA of riboflavin
  • 33% of the RDA of niacin
  • 20% of the RDA of vitamin B6
  • 202% of the RDA of iron
  • 22% of the RDA of magnesium
  • 25% of the RDA of phosphorus
  • 133% of the RDA of zinc

That’s some impressive values—and that’s just the beginning. Chlorella also contains all nine essential amino acids as well as a host of phytochemicals that are known for their impressive health benefits, including carotenoids like lutein, beta-carotene, and zeaxanthin.

Now let’s take a closer look at some of the impressive health benefits of chlorella.

Weight Loss

Chlorella has been shown in studies to help regulate metabolism and even reduce body fat. For example, a study published in the Journal of Medicinal Food found that participants who took supplemental chlorella experienced a noticeable reduction in body fat as well as cholesterol and blood sugar levels.


Similar to the study just mentioned, a clinical trial in the journal Obesity Research & Clinical Practice found that mice fed high-fat diets that included additional chlorella had a reduction in known risk factors for type 2 diabetes, with improved glucose tolerance and insulin sensitivity as well as decreased growth of abdominal fat cells.

In addition, a study in the Journal of Nutritional Science and Vitaminology found that diabetic rats given chlorella nutritional supplements experienced fewer cataracts—a known complication of diabetes.


As mentioned, chlorella’s high chlorophyll content makes it an extremely effective chelator of heavy metals. Some studies have also found that chlorella can inhibit absorption of radioactive particles, including strontium-90 and cesium-137.

In addition, a study published in the Journal of Medicinal Food found that women who were given supplemental Chlorella pyrenoidosa during pregnancy had lower levels of dioxin in their breast milk. This finding is especially significant, as dioxins are highly pervasive environmental pollutants that accumulate in fatty tissue and are linked to a number of health problems, including cancer, diabetes, birth defects, learning disabilities, and respiratory and immune system issues.


A small study in the Journal of Clinical Biochemistry and Nutrition found that participants given 15 chlorella tablets twice a day for 4 weeks experienced significant increases in oxygen uptake during exercise compared with participants who received a placebo.

Immune Health

A 2-year study of individuals with a history of brain tumors, published in the journal Phytotherapy Research, found that participants given supplemental chlorella in the form of Chlorella pyrenoidosa experienced an improvement in overall health and immune system function, including fewer respiratory and flu-like illnesses.


A study published in the Journal of Zhejiang University Science B found that Chlorella vulgaris inhibited cancer cell proliferation and induced cell death in liver cancer cells. In addition, a study in the journal BMC Complementary and Alternative Medicine found that Chlorella sorokiniana inhibited tumor growth and induced cell death in lung cancer cells.

Heart Disease

A meta-analysis published in the journal Clinical Nutrition found that chlorella supplements had a significant positive effect on a number of factors associated with the development of heart disease, including cholesterol levels, high blood pressure, and fasting blood sugar levels.

Brain Health

A study in the journal Molecules found that the carotenoids in various species of microalgae, including chlorella, protect the brain against neuronal damage and cell death linked to oxidative stress, leading researchers to conclude that microalgae may be helpful in the prevention of neurodegenerative diseases such as Alzheimer’s disease.

Chlorella Superfood Benefits

Does Chlorella Have Any Side Effects?

While most people experience no issues with chlorella, some have reported nausea and abdominal upset. In addition, it’s important to note that chlorella does contain moderate levels of iodine. So if you have an iodine-sensitive thyroid condition, you should avoid chlorella.

Moreover, because it has a stimulating effect on the immune system, individuals with autoimmune disorders should speak with a qualified health care practitioner before consuming chlorella.

Some sources also warn against using chlorella due to the presence in its cell walls of endotoxins called lipopolysaccharides—compounds that are also found in gram-negative bacteria and have been associated with negative immune system effects that can lead to inflammation.

However, the comparison of the lipopolysaccharides in chlorella with those in gram-negative bacteria is based on an early study, and more recent studies have shown that the lipopolysaccharides in chlorella behave differently than those found in gram-negative bacteria.

Also, as mentioned earlier, chlorella is extremely sensitive to its growing conditions and can absorb any toxins it comes into contact with, so do your research and be sure to look for a supplier whose products have been tested for safety and purity.

All caveats aside, based on the evidence, it’s pretty clear that while chlorella may be a tiny green alga, it certainly does pack a punch. So go forth and sprinkle some chlorella powder in your favorite smoothie or toss back some chlorella tablets with your favorite beverage—and enjoy those health benefits!

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