Some scientists say it was the first organism on earth. It’s a single-celled plant that’s believed to be the same today as it was at the start.
So how complicated can it really be?
More than you might expect!
Chlorella is freshwater green algae. Since it’s made of one cell, it’s a sphere that’s 2 to 10 micrometers. Spirulina is different; it’s a freshwater blue-green algae (cyanobacteria) and is made of multiple cells. They form a spiral-shape that can be up 100x larger than chlorella.
The cell wall of spirulina is soft and permeable; similar to gram-negative bacteria. You can eat it raw and unprocessed, because the wall is easily broken down by stomach acid.
Even though chlorella is smaller than spirulina, it’s harder to digest because it has a tough cell wall made of mannose, glucose, and cellulose. Without cracking or breaking it, there are concerns about the bioavailability of nutrients when humans eat it. (1) (2)
Seaweed is not a scientific term. While some people call them that, they don’t really qualify under the common or culinary definition. Unlike kelp, kombu, and nori, they are microscopic and most people don’t think of seaweed as being such.
For dietary supplements, there are two species of spirulina used:
- Arthrospira platensis
- Arthrospira maxima
For chlorella, they are:
- Chlorella vulgaris
- Chlorella sorokiniana (formally C. pyrenoidosa)
Claims that C. pyrenoidosa is better for detox and that C. vulgaris is easier to digest are unproven. Their origin is probably rooted in marketing hype.
For each type of algae, the two species sold only have subtle nutritional differences. For that reason, we won’t get into the nitty-gritty between them in this review.
Is chlorella or spirulina better?
When it comes to the basic nutrition facts, both chlorella and spirulina are made of around 55-65% protein, have 8-9% fat content, and are low in carbs at 8-23% by weight. A one ounce serving of either will provide you with 30-70% of the daily value for the B vitamins thiamin and riboflavin. It’s around 20% for niacin, B6, and folate.
Neither chlorella or spirulina are good sources of vitamin C. They only have 2.8mg per ounce, which is 5% of the daily value for adults.
Chlorella is a better source of vitamin A, iron, and zinc. One ounce provides around 290% of the daily value for vitamin A, compared to only 3% you get with spirulina. Iron is around 200% versus the 50% you get with spirulina. (3) (4)
Is there vitamin B12 in chlorella? The brand Sun Chlorella lists it on their nutrition label, however scientists dispute whether or not the compounds are true B12.
Chlorella, along with spirulina, contain what are called B12 analogs or pseudo-vitamin B12. They are molecularly similar to cobalamin, which is real B12. In dietary supplements, it’s in the form of methylcobalamin and cyanocobalamin. It remains unproven as to whether microalgae are a source of vegan vitamin B12 that is bioavailable to humans.
Speaking of which, both of these microalgae are vegan. With the exception of gelatin capsules, animal-derived ingredients are not normally added.
Both spirulina and chlorella are gluten free and non-GMO. There’s no genetically modified version. At least not yet.
The biggest difference between the two come from phytonutrients which you won’t find on the nutrition facts label.
Chlorella is the richest source of chlorophyll, a potent antioxidant. That’s what gives it the true green color, unlike spirulina which is blue-green. In addition to more vitamin A (beta-carotene), chlorella also has higher amounts of other carotenoids like lutein and zeaxanthin. For that reason, it may be better for eye health versus spirulina. Research suggests these phytonutrients may help protect against the formation of cataracts and progression of age-related macular degeneration (AMD). (5) (6)
Spirulina contains C-phycocyanin. It’s a rare antioxidant which is responsible for the exotic bluish color. In lab research, phycocyanin is being studied for potential anti-cancer activity and detox benefits, by influencing liver and kidney function. (7) (8) (9) (10)
Raw spirulina is better than unprocessed chlorella because it’s easier to digest. If it’s in a digestible broken cell wall form, chlorella is equally nutritious for protein and offers an edge for carotenoids and the essential minerals zinc and iron. Spirulina is better if you want the blue pigment, phycocyanin. That antioxidant may offer different benefits.
Pills or powder
There are potential advantages of choosing spirulina and chlorella tablets vs. powder.
The first is convenience, as tablets are portable and not messy.
The second is oxidation. If the tablet is coated, it prevents air from oxidizing the algae. Even without a coating, chlorella and spirulina tablets are typically made by pressing loose powder together in a mold while it’s wet. That alone reduces future contact with oxygen, such as that which may occur with loose powder moving around in bag.
Masking the flavor is another benefit. The intense green taste is not to everyone’s liking, which makes pills and tablets preferable. However, the tablets are intended to be chewed, so you will still taste the.
The advantage of going with chlorella powder instead of tablets is that there are no binders or fillers used. Often times, it’s also more economical for larger dosages. Chewing 10 or 20 tablets a day can be expensive when compared to buying bulk powder.
As long as powder is stored in packaging which protects it from air and light, its nutritional value should be the same as taking spirulina and chlorella tablets, for all intents and purposes. The form you take doesn’t really matter, so long as the source is reputable. Base your decision on preference.
Since spirulina is easy to digest without modification, the best form to buy will be one that’s raw and unprocessed. The most important factor in choosing a brand has to do with safety.
There are dangerous side effects of spirulina when they’re grown in water contaminated with similar species of blue-green algae that produce the neurotoxin known as BMAA.
Recent research suggests BMAA may be a cause or contributor of amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease.
Scientists can actually reproduce the pathology of these diseases in monkeys when they are exposed to food contaminated with BMAA.
Upon testing spirulina-containing products that were purchased at retail in Canada, a 2015 study reported that 14 out of the 39 were contaminated with BMAA. (11)
While any open body of freshwater may harbor dangerous pathogens and species of algae, so far the research suggests BMAA contamination is a problem most relevant to blue-green algae (cyanobacteria).
Since chlorella is a green algae and single-celled, it’s easier to differentiate between cyanobacteria. BMAA contaminated chlorella supplements are not being reported.
Pure spirulina and chlorella are both 100% safe to eat. However given the known risk of BMAA-producing blue-green algae growing alongside spirulina, chlorella is the safer choice overall. Especially during pregnancy, while breastfeeding, and for toddlers and children.
There are plenty of safe and trustworthy spirulina suppliers and brands like Cyanotech (Nutrex Hawaii) and Earthrise Nutritionals (largest producer on earth). However, as long as there are other suppliers who don’t have the same quality control and safety protocols in place, the spirulina category will continue to have a major safety concern.
Something else that’s potentially unsafe is heavy metal contamination.
Depending on where and how they’re grown, even organic chlorella and spirulina can contain elevated levels of lead, arsenic, cadmium, and aluminum.
If they’re grown outside in open pools, rainwater carrying industrial pollution can contaminate them. The same can happen with indoor grown if the water supply is tainted.
China, Taiwan, Japan, and South Korea are the world’s largest exporters of microalgae.
What is cracked cell wall chlorella?
In order to be digestible by humans, the thick cell wall must be opened. Cracked or broken cell wall chlorella accomplishes this through high or low pressure treatment. This fractures or fragments the outer layer, so the inner nutrients are bioavailable.
Within the supplement industry, there are several techniques used for opening the cell wall. These are pitted against one another in marketing claims, as many brands will be adamant that their method is best.
What is Pressure-Release?
With the Pressure-Release method, chlorella are passed through a chamber which causes a rapid change in pressure. This only lasts a few seconds, yet it’s long enough for it to cause the cell walls to gently rupture. They are not completely crushed, which is why they’re called cracked or broken wall.
The advantage of Pressure-Release is that nothing physically touches the chlorella since only sound waves are used. There’s no risk of heavy metal contamination, such as lead, arsenic, or cadmium, which could wear off old presses and milling equipment. It’s raw chlorella since heat isn’t generated, as milling often causes.
Pressure-Release is a new method which has only been on the market for about a decade. It’s also known as vacuum pressure differential, which is the non-trademarked name for it. The nutrients are 80-85% digestible, according to the USDA certified organic Taiwan chlorella brand, Bio2go.
What is Dyno-Mill?
Developed in the late 1960’s, Dyno-Mill is what’s called an agitator bead mill. Within an enclosed chamber, there are discs which spin glass beads along with the chlorella. The beads are then separated using a screen, leaving behind the chlorella which now have their walls open.
The UK company Sun Chlorella reports that the Dyno-Mill process offers the best digestibility, since 90% of the cell wall is pulverized. It’s broken into finer particles versus the larger pieces, as seen with other broken or cracked cell wall methods.
What is sound vibration technology?
Newer than Dyno-Mill but older than Pressure Release, sound vibration technology was developed by German scientists. It uses high frequency sound waves to vibrate the chlorella so their cell walls crack open. The end result is similar to Pressure Release. The walls are not pulverized like they are with Dyno-Mill chlorella.
As with Pressure Release, an advantage of sound vibration treatment is that other materials, such as metals, glass or plastics, are not used to exert high force against the algae.
Other methods (blanching, cold-mill, spray dry)
These are old-fashioned methods which are generally not preferred because higher amounts of antioxidants and vitamins can get destroyed.
Boiling or blanching chlorella will open the walls but at the same time, degrade phytonutrients.
Cold-milling chlorella doesn’t involve intentionally added heat, but anytime intense friction is generated there will be heat created. While a couple cycles is unlikely to generate heat, with that equipment running for hours, you can bet the temperature on the surface of the metal will heat up significantly.
Spray dried chlorella uses a concentrated solution of algae, which is jet sprayed into a hot air steam. The advantage is that the spray dries instantly and it does an excellent job at freezing the degradation process. Spray-dried chlorella won’t expire for many years. The disadvantage is that sprayed air is hot; up to 135°C (275°F). That means at least for a moment, these one-celled plants are exposed to a boiling temperature.
What is fermented chlorella?
Kimchi and pickled cabbage may be considered superfoods, however the fermentation process involved here is something quite different.
With pickled cabbage, it’s allowed to grow naturally in a field. After that, it is harvested and fermented.
Not so with this form of algae.
There is a big difference between fermented chlorella vs. chlorella that’s cracked cell. The latter is grown naturally, while the fermented is grown in complete darkness. Acetic acid and glucose is used to stimulate growth.
Since no sunlight or artificial light is involved, the fermented live their entire lives in sealed tanks. Prior to harvest, boiling temperatures are used to sterilize the algae and kill off any bacteria or other pathogens that might be present.
It’s also marketed as thin cell wall chlorella. Allegedly they have a soft and thin cell wall “because extra protection from outside toxins is not needed” since they’re grown in a sterilized environment. That’s according to marketing for the Dr. Mercola supplement which uses it.
The advantage of fermented is that since it’s not grown in open outdoor pools, there are no concerns about rains rich in pollutants falling down upon them. That can be a major problem everywhere but particularly in China, which is one of the top exporters of sunlight grown chlorella and spirulina.
The disadvantage of fermented chlorella is that some nutrition fact labels for it report lower amounts of B vitamins, K1, iron, and calcium. It also tastes different than that which is grown under natural or artificial light. It can have a processed food flavor.
What is the best chlorella?
Right of the bat, you can cross off the raw and unprocessed forms. This is perhaps the only food you actually want processed, so it’s digestible.
While the fermented might have a thinner wall, nutrient density may be lower. There are also concerns about the heat of sterilization and that one thing that just doesn’t seem right… chlorophyll being produced without light.
Dyno-Mill chlorella is best at pulverizing the outer cell wall, but some people express concerns about the man made materials inside which are also moving around; glass beads and discs made from plastic or metal.
Sound vibration and Pressure-Release chlorella are the best choice. Both use sunlight grown algae and neither involves significant heat or the use of foreign materials, like the glass beads with Dyno-Mill.
Among the countries which grow and export, Taiwan has the best reputation for cleanliness and safety from metal contamination. That’s according to 17 different products which were tested by Health Ranger. They sell their own under the brand Clean Chlorella. It’s cracked cell wall (not fermented).
Clean Chlorella SL is USDA certified organic and grown under natural sunlight in Taiwain, fed using mountain spring water. You can buy the tablets on Amazon.
If you prefer indoor grown so there’s no rainwater exposure, their Clean Chlorella (without the “SL” at the end) is a good choice. It’s grown in South Korea. They do not certify it as organic since it’s grown inside. You can get this powder on Amazon.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.