Is Chlorella Good For You?

Is Chlorella Good For You?
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Chlorella does not have the toxins that may be present in blue-green algae supplements and spirulina.

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What about chlorella, sold as a dietary supplement? Harmful? Harmless? Or helpful?

There was a report in the Journal of Veterinary Pathology of a golden retriever killed by chlorella; it invaded her body, and started eating its way up to her brain. This is showing the algae creep up her spinal cord.

But this is only if you dip an open wound into a scummy pond or something. The chlorella that’s in the health food store is dried and dead.

There have been reports of adverse reactions. For example, here, an 11-year-old hospitalized for kidney failure, which went away when he stopped chlorella. But, this was thought to be an allergic reaction.

Similarly, there are reports of sun-sensitive rashes, and asthma triggered by breathing the stuff in. But again, they don’t appear to be caused by a toxin, like you might find in blue-green algae supplements or spirulina, but just more rare reactions in sensitive individuals.

For the vast majority of people, chlorella can be considered helpful. Packed with lots of nutrients, like tiny little dark green leafies. Kinda tastes like you’re drinking your lawn, though, and kale is cheaper.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by veganmontreal.

Please consider volunteering to help out on the site.

What about chlorella, sold as a dietary supplement? Harmful? Harmless? Or helpful?

There was a report in the Journal of Veterinary Pathology of a golden retriever killed by chlorella; it invaded her body, and started eating its way up to her brain. This is showing the algae creep up her spinal cord.

But this is only if you dip an open wound into a scummy pond or something. The chlorella that’s in the health food store is dried and dead.

There have been reports of adverse reactions. For example, here, an 11-year-old hospitalized for kidney failure, which went away when he stopped chlorella. But, this was thought to be an allergic reaction.

Similarly, there are reports of sun-sensitive rashes, and asthma triggered by breathing the stuff in. But again, they don’t appear to be caused by a toxin, like you might find in blue-green algae supplements or spirulina, but just more rare reactions in sensitive individuals.

For the vast majority of people, chlorella can be considered helpful. Packed with lots of nutrients, like tiny little dark green leafies. Kinda tastes like you’re drinking your lawn, though, and kale is cheaper.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by veganmontreal.

Please consider volunteering to help out on the site.

Doctor's Note

For more on chlorella, check out Treating Hepatitis C with Chlorella.

Also check out my other videos on spirulina and blue-green algae supplements. 

For further context, see my associated blog post: The Best Foods: test your nutrition knowledge.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

59 responses to “Is Chlorella Good For You?

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    1. Hi Dr. Gregor ,
      I am reading your book, and it is very helpful. It was part of the reason my husband became whole food plant-based.
      We are both confused about the omega-3 fatty acid. I understand you recommend supplements. That is 250 mg of pollutants free Long chain omega-3’s. But I am confused as what to get. Some of the supplements are very expensive. Could you expand on that a little. We do take the flax every day and eat lots of greens for the ALA type.
      Thank you

      1. Gail,

        Kudos on the flax daily both in terms of the getting some fiber and ALA. Your absolutely correct that there are no lack of claims and thoughts about what might or might not be the best in terms of the quality of supplement, let alone the source……and a ton of other claims.

        With that said you might want to research a few of the criteria for good quality of omega 3’s. Lets start with an example from the fish source. Take a look at the assays from, as an example Nordic Naturals…. Extensive and well reviewed.

        Many of the same criteria are applicable to the algae form, and most algae supplements are produced under controlled laboratory conditions. Add to this a review of published studies and they concluded see in bold…

        In the Journal of Nutrition. Researchers from the Wellness Institute of the Cleveland Clinic, the Dept. of Nutrition and Dept. of Epidemiology at Harvard School of Public Health, Channing Laboratory, Brigham and Women’s Hospital and the Harvard Medical School conducted a systematic review of randomized controlled trials published between 1996 and 2011. They found that supplementation with algal DHA reduced triglycerides and raised HDL-cholesterol. This was similar to what had been reported. However, algal DHA also raised concentrations of LDL-cholesterol, although the increase was accompanied by a change in the type of LDL cholesterol to the larger, less-atherogenic form. Further research is recommended because many of the studies reviewed were funded by industries.
        For now, DHA from algae seems to be a sustainable, alternative source of DHA that can satisfy both the demands of consumers and the needs of vegetarians, as well as fulfilling most, if not all, the health benefits currently established with omega 3s.

        What you may want to assess with the various brands is their level of reporting for all of the criteria, heavy metals, etc. and then also take into account if the amounts of both DHA and EPA are comparable in price to other formats.

        BUT…. you will also want to note the predominance of DHA , not EPA…. in most of the formulations…….at a premium price compared to the fish source.

        So what to purchase….dependent on your considerations of source……….quality supplements always report their ongoing findings for the contaminants and do 3rd party checks (assays) for multiple aspects of their formulations, including oxidation of the oil which is essential. Look for specific numbers and not the label claims of “pure” “natural” and other non-meaningful verbiage.

        Dr.Alan Kadish moderator for Dr. Greger

  1. I am forever indebted to The Healthy Librarian (check out her excellent blog Happy Healthy Long Life) for correcting my confusion of chlorella phylogeny. I had mistakenly lumped chlorella in with blue-green algae, and they’re not even in the same biological kingdom! Unlike cyanobacteria (spirulina and blue-green algae such as Klamath Lake Aphanizomenon flos-aquae), chlorella does not appear to produce muscle, nerve, or liver toxicity.

    1. In regard to Aphanizomenon flos-aquae, I found a paper from 2005 (“Detection of microcystin synthetase genes in health food supplements containing the freshwater cyanobacterium Aphanizomenon flos-aquae”) which states

      …it should also be noted that neurotoxins have never been detected in the phytoplankton from Klamath Lake.

      . As I was unable to find a full-text copy of the 2009 paper referenced in your “Is Blue-Green Algae Good for You?” video, I’m wondering if further testing of Aphanizomenon flos-aquae revealed neurotoxins?

      1. Hi, Jesse. The 2009 paper is not about levels of BMAA in specific algae samples. It is about levels of BMAA in the brains of people with ALS and Alzheimer’s disease. I downloaded the full text of the 2005 paper to which you provided a link, and did not find the quote you included in your comment. In fact, the paper appears to say just the opposite, although it is focused on hepatotoxins (liver toxins) rather than neurotoxins such as BMAA. Here is a link to the full text document I found:
        https://pdfs.semanticscholar.org/6dc8/56b75fd291ec6965e5bc51bbcfee317d8444.pdf
        You might also be interested in this:
        https://www.researchgate.net/publication/244991099_Human_Exposure_to_Cyanotoxins_and_their_Effects_on_Health
        A quick search did not reveal any new information on toxins in samples of algae from Lake Klamath.
        I hope that helps!

        1. Thanks for the information Christine! The quote I referenced can be found at the end of section 4 (though due to spacing in the PDF, a direct text search may not locate it). I’ll look over the material again in more detail (as I only skimmed it before), but it sounds like the safest thing is just to avoid the substance.

    1. Are you still having problems viewing the video? Live chlorella can indeed infect humans and animals, but what we buy in stores is dried and dead and therefore harmless (but you still might not want to take dips in scummy ponds with open wounds).

  2. Doesn’t the Chlorella Growth Factor call for some concern in humans? Wouldnt this be similar to IGF, promoting unnecessary growth of our bodies?

    1. I’ve never even heard of that! Do you know if that’s just some marketing ploy or a real entity? I couldn’t find anything in the National Library of Medicine database under that name. But if you can find out what it’s really called (if it indeed even exists) I’d be happy to hunt down info about it.

      1. Dr Greger,

        Could you do a video on the link between DHA and IGF-1 as this study points out https://www.ncbi.nlm.nih.gov/pubmed/22337227 ? I was almost going to take a plant based DHA supplement but according to this study DHA could increase IGF-1 and I saw from your other videos that raising IGF-1 is not good. Although the study was done using fish oil and not a plant based DHA supplement… just wanting to know more about this kind of stuff.

        I’m working my way through your 1,300 + videos, thank you so much for your work, most probably extended my lifespan!

        1. Jared Chan: Here’s something to consider: The dose used in the study is more than 4 times the amount that Dr. Greger recommends. You can make any food or substance look bad if you use mega amounts more than is natural or recommended to take in.

          My thoughts: I am by no means an expert or knowledgeable about this data. However, at this point, I don’t think we know whether or not the recommended amounts of DHA trigger dangerous IGF-1 spurts or not. I don’t think? it’s been tested. So, you are left with looking at the evidence that Dr. Greger has for recommending DHA supplementation and deciding if that evidence is strong enough to outweigh this (among others) unknown. Is the evidence in favor of DHA supplementation strong enough to overcome concerns?

          Dr. Greger thinks so, which is why he recommends DHA supplements. However, everyone must make up their own mind. You can decide this for yourself since the DHA recommendation is not like the B12 recommendation. (Everyone on a plant based diet needs to get their B12. That is not in doubt.)

          What do you think?

    2. You have raised an interesting possibility. Have you come to any conclusions or obvious reasons to avoid ingesting chlorella, in regards to IGF similarities? I have always had some concerns with chlorella, and would not be surprised to see a study in the future showing negative attributes, yet many vegans just adore and have gratitude for the product.

  3. Dr. Greger,
    I am currently going through a Detox therapy due to some heavy metals contamination (G.I. Tract, etc – mainly Hg – Mercury). Chlorella was prescribed by my M.D./Biochemist Nutritionist/and Nutritionist both Ph.D). I was surprise to see on your DVD #5 that your recommendation was to stay away from it due to BMAA bacteria. In my research some companies test to ensure their product is BMAA tested. Do you still recommend to stay away from it. My levels of Hg are coming down and I haven’t even started to do DMPS yet.
    Thank You!
    Aramis Ortiz
    San Diego, CA

    1. Gary Birch-Spain
      Have you checked facebook on the Detox Agency, or maybe even pernilledamore.com, you could even look at the Gerson Therapy web site for detox information and guidance.
      Regards
      Gary
      Spain

  4. Note: In the analysis done it showed that I have Mercury, Aluminum, Lead, and Arsenic. Natural chelation with Chlorella and cilantro is one process. Synthetic aminoacid such as DMPS and DMSA is another method. I also did a one week Sauna Detox.
    Again Thank You!
    Aramis Ortiz
    San Diego, CA

  5. If any algae is grown hydroponically do you still have to worry about toxins? If spiralina is grown hydroponically can I take it along with chlorella?
    Thank you in advance for your advice.

    1. The issue is not with how the spirulina is grown but what byproducts are produced by it. Therefore it shouldn’t matter how the spirulina is grown.

  6. Hello,
    Recently I have read an article that have create on me confusion about cholorella. This article, which source is natural news, was explaning that most of the cholorella that we consume comes from China, Japan and Korea has a very high concentration of Aluminiun. Have you heard something about it? Do you have some information, research that prove this fact or clarify a litlle bit this issue. Wre live in World that we do not know who we trust even brands that they are bio they are doing funny things and at the end they get money through or most precious give our health. I would appreciate all the information you can share with us.
    Thank you.

  7. Dear Dr Greger,
    Thanks for all your hard work. Blue-green algae are out, but how are we to know the colour of the algae in vegan omega 3 supplements ? Would you happen to know if they are safe here in Europe, i.e. toxin-free? Thank you.
    Ps Your work deserves international recognition, the whole world should benefit from it. A suggestion: I have a degree in translation, say I were to translate one of your transcripts into Dutch, would you be able to use it in any way? Or is it too soon for such a leap?
    Gratefully yours,
    Barbara

  8. Spirulina is not known to have any toxins or to affect the liver…. that is AFA from Klamath Lake…. they are not the same.. US grown Spirulina is always clean… not so if it comes from China (Chlorella has the same issue of toxins when it comes from China) Dr. Christopher Hills (the father of Spirulina) was the primary researcher of Chlorella for 12 years (he had the Chlorella International Union) along with his partner Dr. Hiroshi Nakumara… they shifted their research & promotion to Spirulina when it was found to be much more compatible with the human body…. and to have more nutrition to boot. I have been marketing, studying & taking Spirulina for 32 years… I can’t say enough about what it does for the human body. Now with Fukushima, it is imperative that we get it out to as many people as possible…. it is one of the few algae’s that have medical research/practice on the positive effects it has on people who have radiation exposure.

  9. I started taking some chlorella from china which was supposed to be grown and purified in a lab. Everything was fine for about 5 weeks then I noticed after about 2 hours of taking it, I would vomit. This happened 3 times, about a week apart, while I backed off taking the chlorella in the days between. The last time I was pretty sick. I haven’t taken it since. The literature said if something like that happened that a person taking the chlorella should increase the dose, even though it didn’t seem logical—their comments,not mine. It said the body was detoxifying and finally getting rid of stuff. I wasn’t under a doctor’s supervision and felt if I took it anymore, I didn’t know what would happen. Any thoughts about reactions to this product?

    1. I think it sounds more like that your body had had enough of the Chlorella. I think that when the body has had enough of something, whether it be certain kinds of food which may or may not agree with you, even chocolate, you will start to feel sick, perhaps even vomit, if you try and eat more and more of it. I don’t think it’s a sign of the body “finally detoxifying itself”. And I don’t think it means you should start eating more of what is making you feel sick. I think it is the body saying it has had enough of whatever you have been consuming.

    1. Many of the algae mimic the cobalamin (B12) structure, but they are not absorbed like B12 and cannot be relied on as a B12 source.

  10. it took me a long time.. like over 5 years to get to the ending of this video…i just can’t stop laughing….. ~~~ i love to laugh ~~~ thank you :-D

  11. I recently suggested my mother takes Chlorella but it makes her vomit terribly. She is on Enalapril for high blood pressure, Sorvasta for Cloresterol and Levothyroxine for thyroid. Could it be reacting with any of these?

  12. Your last comment that “Kale is cheaper” begs the question: but does chlorella offer any enhanced benefits that we wouldn’t get from Kale? I’m specifically wondering about improved recovery from endurance running. Do you know if there are any studies or reasons to believe one way or another? Also, how do we make sure we are buying a safe brand?

  13. We are a plant based family and I was wondering if a Chlorella supplement is something I should consider giving my teenaged children.

  14. Dear dr. Gregor and his team,
    I am in desperate need of your help. I have been introduced to an article from National library of medicine (which many find as a trustworthy source), that suggests that chlorella could be a viable source of vitamin B12 for us, vegans. Many of us would welcome this option, because eating this vegetable sounds better than taking synthetic supplements, but we want to be sure, that its safe that way. We trust you and your knowledge, so I ask you for advice in this matter.
    The article:
    http://www.ncbi.nlm.nih.gov/pubmed/26485478
    Thank you for everything you do, your work has helped me a lot.
    Yours sincerely,
    Daniel Kostić

  15. Daniel Kostic: Your post got caught in the spam filter. I just released it. Hopefully someone who can address your question will be able to now.

  16. Sounds promising from this study, however I think one of the main issues is that the doses are less clear, and the products are often mixed with other algae, such as spirulina, which have inactive B12 analogues…

  17. What is with the toxine Microcystine, which is dangerous und for the liver and kidney. The WHO warns. Now I don´t what I can doing and eliminate all toxins (Amalagan) Mercury? Or can I take Kale?

  18. I have been taking 5g chlorella daily for about 5 months, and it makes me feel great, but am starting to get worried about this rumor going around (the Paleos started it) that this LPS endotoxin in the chlorella creates pro-inflammatory cytokenes that put your innate immunity on high alert. They warn that it could lead to sepsis and chronic systemic inflammation. That sounds horrible!!!

    They use several studies to back this up, but I don’t have enough scientific knowledge to interpret whether this is really true. Has your research found anything on this? Have you discussed it elsewhere?

    Much thanks.

  19. The available literature I see shows that Chlorella has significant ALA content, so theoretically yes. The problem is that Chlorella makes me nervous because its not something humans evolved to eat and has not been proven safe. In my mind I’m always worried about Testimonials of people “feeling great” is not compelling. Peer-reviewed clinical studies are. My concern is primarily with beta-N-methylamino-L-alanine (BMAA) and the increased risk of neurotoxicity.

    Dr. Ben

  20. I used to take both chlorella and spirulina many years ago; no problems. I’d like to start on chlorella again, but all this info is very confusing. I have Dr. Greger’s books and he puts chlorella in his recipe(s)…So, should we take it or leave it..?

  21. Taking Chlorella for on-going constipation. Became very tired in the afternoon
    and can not sleep at night which is upsetting. Very happy with bowel activity which
    has not been as good in decades. Read Chlorella affects thyroid which has been
    a problem for me for a number of years. Notice recurring rash from mold poisoning
    related immune system disorder has not come back. Will my sleep return? I went
    off Chlorella April 4th because of this. It has been a little over a week. I
    am very much concerned and would very much appreciate knowing.

    The tiredness has gone but still can’t sleep at night since being on the Chlorella. I saw this same problem in a couple of comments on line with regard to Chlorella. I have read it affects thyroid which I am sure is why I can’t sleep and ears ring. and I do have a problem with thyroid since my immune system problem began and can not tolerate any thyroid medications tried even compounded. I was on Chlorella beginning March 17 until April 4th (2018). Thank you very much

    1. Hi Carmen- There is unfortunately a very long list of things that influence sleep quality. These include sleep apnea, overweight/obesity, stimulants, medication use, menopause, stress, anxiety, depression, various illnesses including heart failure, chronic pain. An overactive thyroid gland can cause insomnia as well. An underactive thyroid gland can cause fatigue and sleepiness as well as constipation.

      I’d very much advise you sit down with you doctor to review your medical history, all medications, and discern the cause or causes of your sleep trouble in order to find a solution.

      Good luck! Dr Anderson, Health Support Volunteer

  22. I would really like to start taking Chlorella but it seems impossible to evaluate all the products on the market out there for reliability.

  23. I’ve been searching the net on chlorella for months and finally found a reliable address. I don’t know if this is of any help to you: I live in The Netherlands and it seems that the European/Dutch safety rules are a lot more strict than the American. Products don’t get in if they’re contaminated. I found both amla and chlorella here: https://www.superfoodsonline.nl/

  24. Do you know what type of chlorella Dr. Greger recommends? From what country, what species, and if there are any recommended brands as far as safety concerning heavy metals, etc.? Thank you!

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