Chlorella Benefits & Uses (and When It Can Be Dangerous)

Is Chlorella a Superfood

I’ve raved about Spirulina before and shared how I use it, but Spiulina’s cousin Chlorella is a powerhouse as well.

What is Chlorella?

Like Spirulina, it is a freshwater algae with a host of benefits. Unlike spirulina, it is a single-celled fresh water algae (spirulina is multi-cell). It is also one of the oldest known species on the planet and that has the unique ability to reproduce 8 times a day, making it a sustainable nutrient source.

Chlorella has a very hard outer shell, making it almost completely indigestible to humans, so supplemental forms undergo a special process that cracks this outer shell for enhanced digestibility.

It is one of the most-used supplements in Japan (where most of the world’s supply is produced).

Chlorella Nutrition Facts:

Many sources list this nutrient dense algae as one of the most nutrient dense foods in the world, claiming that:

A 1-ounce (3 tbsp) serving of chlorella contains:

  • Protein—16g
  • Vitamin A—287% RDA
  • Vitamin B2—71% RDA
  • Vitamin B3—33% RDA
  • Iron—202% RDA
  • Magnesium—22% RDA
  • Zinc—133% RDA

While this is true, it would not be cost effective to consume this much daily and doing so might lead to unwanted side effects. Sources that cite that it is more nutrient dense gram for gram than other greens like broccoli and kale are technically correct. It is just much less expensive and more realistic to consume these amounts of broccoli and other greens.

Additionally, since this algae has to undergo a specialized treatment to break down its cellular walls to make it digestible to humans, it is typically more costly than other sources of these nutrients.

It certainly can be beneficial, but it isn’t going to replace a salad or other greens in your daily life.

Chlorella Benefits

Though it may not be a realistic source of nutrients due to its high cost, there may still be some reasons to take this micro-algae.


Chlorella is a source of Chlorophyll, Protein, Iron, Magnesium, and amino acids, but it is primarily known as a detoxifying supplement. Its tiny size and unique properties make it able to bind to heavy metals and unwanted chemicals in the body.

There is some debate about its safety for detoxification, however, as it may remove heavy metals but not bind strongly enough to remove them. This means it may actually increase the heavy metal levels moving around in the body.

It is often used by those undergoing chemotherapy or radiation to help reduce the body’s chemical load, and it is said to support the body’s liver and detoxification pathways without stripping beneficial minerals from the body.

The most studied use for Chlorella in detoxification is in taking small amounts over time to help avoid heavy metal build up in the body. This study showed that it may have a protective effect for mice exposed to lead and other heavy metals.

Important: Anyone who has been exposed to any type of heavy metal should work with a doctor or practitioner who specializes in removal. Removing metals to quickly or with the wrong substances can actually make things worse!

Immune Support

WebMD lists that Chlorella is used to boost the immune system, to aid digestive problems, to increase good bacteria in the digestive system, and for ulcers.

A double-blind placebo study found that regular use increases natural killer cell activity and early inflammatory response. The study reported:

These results may suggest a beneficial immunostimulatory effect of short-term Chlorella supplementation which enhances the NK cell activity and produces interferon-? and interleukin-12 as well as interleukin-1?, the Th-1 cell-induced cytokines in healthy people.

It is important to note that the study only looked at short-term effects and that we don’t know the long-term immune implications. Also, as it does affect the immune system, those with any type of immune problem or autoimmune disease should work with a doctor when taking this or any other immune-stimulating substance.


There is anecdotal evidence that it may help reduce hypertension and cholesterol, increase energy, to reduce asthma attacks and PMS and for relief for those with fibromyalgia.

Difference Between Chlorella and Spirulina

Though they look, smell and even taste similar, there are few key differences:

  • Structure: Both are types of algae, but Chlorella is a true single-cell algae with a nucleus, while Spirulina is a multi-celled plant with no distinctive nucleus. For this reason, spirulina is much larger than chlorella.
  • Color: Spirulina is a cyanobacteria, a blue-green type of algae, while Chlorella is a green algae.
  • Amount of Nucleic Acids: Both are a good source of nucleic acids, though Chlorella has almost twice as much as Spirulina. Nucleic acids are important factors for DNA and RNA in the body.
  • Digestibility: Spirulina can be consumed easily after harvest while Chlorella has to go through a process to break its cell walls before the body can use it.
  • Chlorophyll Content: Chlorella is higher in Chlorophyll, with almost double the amount.
  • Iron, Protein and GLA: Spirulina is higher in Iron, protein and beneficial Gamma-Linolenic Acid (GLA).
  • Heavy Metals: Chlorella has unique properties in its cell walls that make it bind to heavy metals and other contaminants (spirulina does not have this same benefit).


Though generally considered safe, Chlorella comes with some cautions and warnings. It can contain moderate levels of iodine, so those with iodine sensitive thyroid conditions or iodine allergies should avoid it. Those with auto-immune disease should consult with a doctor first as it can increase immune function and may make these conditions worse.

Sources are divided on safety during pregnancy, so pregnant and nursing women should talk to their individual doctors and midwives to evaluate if these supplements would be safe or beneficial for them.

Additionally it can cause a detoxifying effect in some people, and those sensitive to certain types of mold should avoid it as well. Due to its high Vitamin K content, it will increase clotting, so those with clotting disorder should avoid it as well. A great source of iron, it should be used in moderation by men and post-menopausal women.

Finding Quality Chlorella

It is important to find a quality Chlorella supplement as low-quality supplements may contain mercury or not have a cracked cell wall, making them useless to the body. Due to the detoxifying effect, it is also important to start slowly and consult a doctor before using if any health condition is present.

Personally, I have used these brands with good results:

Ever used Chlorella? What was your experience?

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Reader Comments

  1. Thanks for such a valuable information. Though I am a vegetarian, I do follow your blog for health information. I am looking forward to try some of your recipes like kale chips, rice with cauliflower and a few more.

  2. Hi there, I use your website all time and I really appreciate all the info you make available. I wanted to say you’ve got your descriptions of cyanobacteria and green algae a little mixed up. Chlorella is a green algae which is a microscopic plant and is eukaryotic (which means it has a true membrane bound nucleus and other organelles). Spirulina which has now been determined to actually be from the genus Arthrospira is a cyanobacteria. Cyanobacteria are bacterium and are prokaryotic (no membrane bound nucleus) and they are NOT plants although they do have chlorophyll. I’m not an expert in natural health but my PhD research was on cyanobacteria so I do know about that 🙂

  3. Are the warnings specific to diagnosed clotting disorders or can this increase the chances of a blood clot in anyone with poor circulation?

  4. I did not know there was a any concern about taking Spirulina while pregnant (and I read anything and everything). I drank one tablespoon of Spirulina powder with juice on a regular basis when I was pregnant. I like to think it contributed to my daughter’s vivaciousness and intelligence, though all children are amazing!

  5. I would love to know your thoughts on the chlorella I take. I grow weary of trying to figure out which source to use for each of my supplements! I already use this one and can get it for a great price through out co-op. Wondering if I should change or stick with it. I LOVE YOUR SITE and have never commented before but am so thankful for all you do to educate your readers. Thank you!

  6. Hi there

    I thought Chlorrella was supposed to be good for people detoxing from mold. Can I ask you where you heard these people need to be careful?

    Thanks so much

    • WebMD offers that warning, but I’ve seen conflicting info on this too. I’d check with your doc for your specific case.

      • Every time I ask my Dr. after I find something really great, like a supplement, she says: I can’t advise it. You have to do it on your own. Which of course is very frustrating. Of course she can advise all the poison she is putting in my body that is rearranging my brain chemicals. No prob.
        I have a really serious question. If I take any thing that is a detox in any form, I am worried it will take away things that ARE bad but just so happen to be the medicine that Dr. can’t advise it, is giving me. I don’t know how the Dr.’s medicine’s are digested. If they do stick around for awhile, let’s say the liver, ready and waiting for a detox to sweep them up that might not be good. I would LOVE a detox. Do you have any idea how medicine, pill form, are processed in the body? Would I be safe doing a detox without messing with what I am supposed to have there? And even IF I accidentally detoxed some stupid pills, I have to take them again in 5 hours anyway. So its probably cool right?
        ( if you answer ask your dr. or I can’t advise it, your in big trouble Missy. I kid! Even though I already know. Well I am gonna get as much Chlorella as I possibly can and detox for 48 hours straight!!! J/k
        You know I really respect you and love everything you share with us. I spend hours on your site and can barely finish one topic before going to the next. You are super kind to want to share all of this and write at night and stay with the bambinos all day. SO tiring!! Thank you!

        • Hi Shannon… I feel your frustration! I finally had to talk to a naturopathic doctor to get answers on supplements and detoxing. I do know that it isn’t good to take some things, like Chlorella or Activated Charcoal within a couple of hours of taking medicine, but it is my understanding that these natural things only act on the body when they are taken.

  7. I see that one of the supplements is from Japan. You may want to consider not buying anything from Japan or the north Pacific Ocean because of the Fukishima nuclear accident. Wouldn’t want anyone to eat something that is contaminated with radiation.

  8. My kids have allergies to seafood, would this be a no no for them?

  9. This post came at the perfect time!! What do you know of the possible radiation or heavy metal contamination of Japanese chlorella? We are looking to use it for my husband as part of his healing protocol from extreme heavy metal toxicity. Our practitioner suggested it, but we are doing the research for the best source. We don’t want to nullify the benefits by putting back in what he is trying to get rid of! P.S. Do the products you use undergo testing for those, do you know?

  10. How much do you recommend taking? How many tablets?

  11. My daughter has a blood clotting disorder called von willebrands, type A. Her blood actually doesn’t clot well and would need special clotting agent for tooth extractions, surgeries, etc. to make her blood clot. So the vitamin K in spirulina/chlorella would actually be beneficial for her, correct? Seeing the hematologist soon and will ask but just wondered your opinion.

  12. Thanks for the tips on chlorella.
    I just started taking today. I’ll let you know how I feel in 20 days when the box finished. I went to the health food store and they had Sun Chlorella granules. I hope it’s a good one. Aloha.

    • I have been using sun chlorella tablets daily for about 3 yrs. helps with my detoxing, arthritis and fibromyalgia and also constipation. And lots more energy. You may want to check out ordering it throught their online site. i get an order every 3 months which charges to my account and if I want to cange it just call and they are very accomadating. Excellent source in my opinion.

  13. My daughter has red hair and her midwife recommended she take this during pregnancy since supposedly redheads loose more blood.

  14. Hi Katie

    thank you for all the great information as always. I would like to get your opinion being that I truly value it, not to mention that Dr.’s normally don’t have the answers. Have you ever taken chlorella while nursing and what are your thoughts on chlorella from MRH due to the Fukishima nuclear accident. Your input is greatly appreciated.

  15. Hi!
    I love your blog & podcast! Big fan:)
    I have hypothyroidism (on armour) due to my last pregnancy. I was drinking liquid chlorophyll for about 2 wks w/no real benefits except that I didn’t have to wear deodorant lol. I did however experience constipation & some minor weight gain in a short period of time (this isn’t like me). Do you think the liquid chlorophyll had something to do with it. I’m not going to drink it for a few days to see if things normalize.
    I don’t eat gluten & follow a healthy diet so this just seemed strange to me.
    Thoughts? Thank you for your help.


  16. Hi,Katie. Funny you should mention this thing with autoimmune diseases. I’m celiac,have Ray and tons of allergies. I’ve orderd Chlorella to clear out of toxins but when I took it ….:/my circulation just stopped! My lips turned blue,my fingers ice cold. I just could’n warm my self up. I tried it several more times,with the same result. Creeped the h.. out of me!

  17. So what is the best way to consume this and how much?

    • I typically follow the recommendations on the capsules/powder. But I always suggest talking to your healthcare provider first, and starting with smaller doses to see how your body adjusts 🙂

      • Your so correct! My Dr has not a clue, if it wasn’t for my own investigation into health and wellness I would be a full blown diabetic, I hace beat tgere tests everytime! it’s hard finding someone who is holistically based and who takes medical insurance! I bought some today, will follow directions and take it slowly. Thank you for you wonderful site!

  18. Hi. My city recently found out ( 1 week ago) that a teflon by product called Gen X has been dumped in our water supply for the past 5-6 years. It’s pretty serious, and I am over 7 months pregnant. I am taking cracked cell wall chlorella tablets to help get this crap out of my body. Good idea? I can ask my midwives next week as well!