Chlorella vs Spirulina: What Is the Difference?
More on: Supplement Buyer's Guides
Chlorella vs spirulina is the most common comparison in the algae aisle, because the two look alike in a jar, are often sold side by side, and are frequently blended together.
Short answer: spirulina is a blue-green algae (technically a cyanobacterium) with a soft outer layer, a blue pigment called phycocyanin and a high protein content. Chlorella is a single-celled green algae with a tough cell wall, which is why it is sold as "cracked cell" or "broken cell wall". Both are dark green powders. You do not have to choose: many blends use both.
What is spirulina?
Spirulina is the common name for the cyanobacteria Arthrospira platensis and Arthrospira maxima. Under a microscope it is a long, spiral-shaped filament, which is where the name comes from. It grows in warm, alkaline water and is farmed in open ponds.1
Spirulina is roughly 55 to 70 percent protein by dry weight, and its blue-green colour comes from chlorophyll plus phycocyanin, the blue pigment used to make "blue spirulina" powders.1
What is chlorella?
Chlorella is a single-celled freshwater green algae, most commonly Chlorella vulgaris or Chlorella pyrenoidosa. Each cell is a tiny sphere. It is usually grown in tanks or closed systems.2
Chlorella is also high in protein, often around 40 to 60 percent by dry weight depending on how it is grown, and it is a deeper, darker green than spirulina.2,3
What is cracked cell chlorella?
Chlorella has a tough, multi-layered cell wall. To make the contents accessible, manufacturers break that wall during processing, using milling, pressure or other methods. Products sold this way are labelled "cracked cell" or "broken cell wall" chlorella.2 Spirulina does not have the same tough wall, so it does not need this step.
Chlorella vs spirulina at a glance
| Spirulina | Chlorella | |
|---|---|---|
| What it is | Blue-green algae (cyanobacterium) | Single-celled green algae |
| Shape | Spiral filament | Tiny sphere |
| Cell wall | Soft | Tough, needs cracking |
| Colour | Blue-green | Deep green |
| Protein (dry weight) | About 55 to 70% | About 40 to 60% |
| Usually grown in | Open ponds | Tanks or closed systems |
| Taste | Mild, slightly salty, sea-like | Stronger, grassier |
Vitamin B12 in spirulina and chlorella
You will often see algae described as a vegan source of vitamin B12. Be careful with that. Research has found that most of the B12-like compounds in spirulina are a form called pseudovitamin B12, which the human body cannot use.4 Some chlorella products contain the active form, but the amount varies a lot between products.3 If you are vegan, do not rely on either algae for B12. Speak to your doctor or dietitian about a reliable source.
Which is better, chlorella or spirulina?
Neither is better across the board. They are different organisms with different make-ups. Choose on practical grounds:
- Taste: spirulina is usually milder.
- Format: both come as powder or tablets. Powder is cheaper per gram.
- Chlorella: check that it is cracked cell or broken cell wall.
- Quality: buy from a brand that tests its algae. Studies of algae supplements have found that quality varies between products, so the source matters.5
- Or both: a blend gives you both without buying two jars.
Can you take chlorella and spirulina together?
Yes. They are commonly combined, and many greens powders contain both. If you take a blood thinner such as warfarin, speak to your doctor first, as chlorella contains vitamin K.
If you are comparing whole blends rather than single algae, see how to choose a superfood powder in Australia and is greens powder worth it.
What we make
Our daily superfood powder is a blend of eight superfoods: cacao, goji berry, green barley grass, spirulina, beetroot, acai berry, cracked cell chlorella and camu camu. One serve is 7 g (3 slightly rounded teaspoons), there are 30 serves in a 210 g jar, and it is vegan, dairy free and non-GMO. It is packed in Brendale, Queensland, and delivered anywhere in Australia.
It contains both organic spirulina and organic cracked cell chlorella, so you get both algae in one scoop.
For more on getting both algae in a single scoop, see this guide to spirulina and chlorella powder.
Frequently asked questions
Are chlorella and spirulina the same thing?
No. Spirulina is a cyanobacterium and chlorella is a true green algae. They look similar as powders but are different organisms.
Why does spirulina smell like the sea?
It is grown in salty, alkaline water and has a naturally mild, sea-like smell. A strong, unpleasant smell can mean an old or poorly stored product.
Can I take spirulina or chlorella at night?
Yes. Neither contains caffeine. Take them whenever suits you. See when to take greens powder.
About the author
Grant Jenkins is a director of Propel Health Australia and an Accredited Exercise Physiologist. Our range is packed in a licensed facility in Brendale, Queensland. Every figure quoted for our product in this article is the figure on our printed label.
References
- Soni RA, Sudhakar K, Rana RS. Spirulina: from growth to nutritional product. A review. Trends Food Sci Technol. 2017;69:157-171.
- Safi C, Zebib B, Merah O, Pontalier PY, Vaca-Garcia C. Morphology, composition, production, processing and applications of Chlorella vulgaris: a review. Renew Sustain Energy Rev. 2014;35:265-278.
- Bito T, Okumura E, Fujishima M, Watanabe F. Potential of Chlorella as a dietary supplement to promote human health. Nutrients. 2020;12(9):2524.
- Watanabe F. Vitamin B12 sources and bioavailability. Exp Biol Med. 2007;232(10):1266-1274.
- Roy-Lachapelle A, Solliec M, Bouchard MF, Sauvé S. Detection of cyanotoxins in algae dietary supplements. Toxins. 2017;9(3):76.
Disclaimer
This article is general information, not medical advice. Speak to your healthcare provider before starting any new supplement, especially if you are pregnant, taking medication or have a medical condition.
