Chlorella is a green algae that grows in fresh water. It emerged over 2 billion years ago, and was the first form of a plant with a well-defined nucleus. Each Chlorella microorganism is composed of a nucleus, starch grains, chloroplasts and mitochondria surrounded by a cell wall composed mainly of cellulose. Because Chlorella is a microscopic organism, it was not discovered until the late 19th century, deriving its name from the Greek, "chloros" meaning green and "ella" meaning small. There are various species of chlorella. Although the algae grow naturally in fresh water, Chlorella destined for human consumption is generally cultivated in large, fresh mineral water pools under direct sunlight.
   Although chlorella was discovered by a Dutch microbiologist in 1890 and studied as a potential protein source by German scientists, it wasn't until after the Second World War that the reality of food shortages, combined with the expectation of a population boom, led to bureaucrats globally examining chlorella in the hope that it could be used to feed the masses cheaply – this proved uneconomic. Later, NASA studied it with the possibility of feeding it to astronauts. It is currently being used in some countries to help cancer patients.

What does the research say about the benefits of chlorella supplements?
I could only find a few studies with chlorella involving humans. Based on very early research, it appears that chlorella may play a role in fibromyalgia, hypertension, or ulcerative colitis and has an effect on the immune system. We definitely need a few more studies to confirm initial findings.

Purchase Chlorella supplement, 500 mg per pill
Chlorella is a green single-celled microalgae that contains very high concentrations of chlorophyll.  Before being used as a supplement, it must be gathered, dried to a paste, crushed to a fine emerald green powder, and converted to tiny, soft, crumbly tablets, which smell vaguely of the sea. Chlorella also supplies high levels of Beta Carotene, Vitamin B-12, Iron, RNA, DNA and Protein.  The cell wall in this high quality Chlorella has been broken down mechanically to aid digestability.  Each serving typically contains: Chlorophyll 25 mg, RNA 35mg and DNA 3mg.

Supplement Facts
Chlorella Powder (Chlorella vulgaris) - 500 mg per capsule

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Q. What is the difference between chlorella broken cell and the unbroken cell version?
   A. The outer cell wall of chlorella has a low digestibility, which requires an opening to digest its nutrients. A variety of methods are used by different makers to break down the cell wall to enhance its digestibility. The broken cell version will have a higher absorption rate than the unbroken cell.

Helps improve overall health
Japanese researchers claim that this green algae could reduce body-fat percentage and blood-glucose levels and help those who have type 2 diabetes, obesity, cancer patients or those with heart disease. This supplement could boost energy and improve mood. Some claim that chlorella stimulates the growth of probiotic or friendly bacteria, and its cell walls absorb toxins within the intestine and encourage peristalsis. Randall Merchant, professor of Neurosurgery and Anatomy at Virginia Commonwealth University, in the US, researches brain tumors, traumatic brain injury, and stroke. In 1986, he began clinical trials, funded by chlorella producer Sun Chlorella 'A', into whether the algae might improve a patient's immune system. "Fascinating," is how he describes the results. "It didn't make brain tumours go away or shrink, so it didn't cure the cancer, but it did help the patients by boosting their immune system so that they resisted opportunistic infections." Since then, Prof Merchant has performed clinical trials to test whether chlorella could be useful in helping with chronic conditions such as fibromyalgia, ulcerative colitis and hypertension. In the first two trials, his team found that "patients' symptoms diminished quite nicely". For hypertension, the results were more dramatic; while it lowered blood pressure in about 50 per cent of cases, which was promising, the studies showed that it also significantly lowered serum cholesterol. In 2008, he examined the effects chlorella has on those with metabolic syndrome – the collection of symptoms that often lead to the cells in our bodies becoming less sensitive to insulin, and therefore a precursor to diabetes. Chlorella turns on the genes that control the way insulin is normally used by the cells in the body and may be of benefit to those with metabolic syndrome.

Antioxidant benefit and eye health
Antioxidant and anti-cataract effects of Chlorella on rats with streptozotocin-induced diabetes.
J Nutr Sci Vitaminol (Tokyo). 2003 Oct;49(5):334-9.
The antioxidant activities of chlorella in vitro and in vivo were investigated. Chlorella showed a strong antioxidant effect compared to various vegetables. To evaluate the antioxidant and anti-cataract effects in vivo, a 7% Chlorella powder was fed to rats with streptozotocin-induced diabetes for 11 weeks. At the end of the experiment, chlorella had decreased the blood glycated hemoglobin (hemoglobin A1c) and serum cholesterol levels significantly, however, it had not affected the serum glucose concentration. The serum lipid peroxide value (TBARS value) in the rats fed chlorella was lower than that of the control rats. In the liver and kidney, Chlorella also reduced chemiluminescent intensities. In addition, it delayed the development of lens opacities. These results indicate that chlorella has antioxidant activity and may be beneficial for the prevention of diabetic complications such as cataracts.

Chlorella side effects, safety, risk, toxicity
Although no significant chlorella side effects have been reported in the medical literature, we have had several reports of gastrointestinal side effects with the use of chlorella supplements. These chlorella side effects involved nausea and vomiting. See below.

I read on your website about people having side effects from chlorella supplements and I too have experienced gastrointestinal upset. I have tend to have a sensitive bowel, but thought that chlorella was beneficial for this. Also I suffer from fibromyalgia and migraine. I had tried a year ago New Chapter Chlorella on one occasion and do not recall having any problems. However, when I bought and took two tablets of brand called Organika I got sick on two occasions. The first time I got severe nausea and flu like symptoms within a few hours of taking two tablets. Miraculously, drinking ginger tea cleared up the symptoms quite quickly. I tried the Organika Chlorella a week later just in case it wasn't the supplement that had made ill. Again within a few hours, I wasn't nauseous, but I had severe cramps and then diarrhea, which fortunately was short lived. (email received March 2009)

I started taking chlorella and got a really stuffed nose. I suspected it was the chlorella, and as soon as I stopped taking it I could breathe again! Thought you might want to add this to your side effects testimonials. (email received March 2010)

Chlorella Research study
It is a tiny, unicellular green algae, three to eight micrometres in diameter, which when grown in large quantities gives lakes and rivers a green tint.

Improved separation method for highly purified lutein from chlorella powder using jet mill and flash column chromatography on silica gel.
J Agric Food Chem. 2004 Oct 6;52(20):6283-6.
We investigated an improved method for the separation of high-purified lutein from a commercially available spray-dried Chlorella powder using fine grinding by jet mill and flash column chromatography on a silica gel. Saponification and extraction of lutein were enhanced 2-fold in jet mill-treated Chlorella powder (mean particle size, 20 microm) as compared to untreated Chlorella powder (mean particle size, 67 microm).

Effects of chlorella on activities of protein tyrosine phosphatases, matrix metalloproteinases, caspases, cytokine release, B and T cell proliferations, and phorbol ester receptor binding.
J Med Food. 2004 Summer;7(2):146-52.
A Chlorella powder was screened using 52 in vitro assay systems for enzyme activity, receptor binding, cellular cytokine release, and B and T cell proliferation. The screening revealed a very potent inhibition of human protein tyrosine phosphatase activity of CD45 and PTP1C. Other inhibitory activities and their IC(50) values included inhibition of the human matrix metalloproteinases and the human peptidase caspases, as well as release of the cytokines interleukin (IL)-1, IL-2, IL-4, IL-6, interferon-gamma, and tumor necrosis factor-alpha from human peripheral blood mononuclear cells. Chlorella also inhibited B cell proliferation in mouse splenocytes and T cell proliferation in mouse thymocytes. These results reveal potential pharmacological activities that, if confirmed by in vivo studies, might be exploited for the prevention or treatment of several serious pathologies, including inflammatory disease and cancer.

A hot water extract of Chlorella pyrenoidosa reduces body weight and serum lipids in ovariectomized rats.
Phytother Res. 2004 Feb;18(2):164-8.
The effects of a hot water extract of Chlorella pyrenoidosa, which contains chlorella growth factor, on the body weight, serum lipids, and the bone mass were evaluated using an ovariectomized rat as a model for postmenopausal bone loss. Rats were divided into four groups: sham-operated (Sham), Sham given the chlorella growth factor solution, ovariectomized (OVX), and OVX given the chlorella growth factor solution, respectively. Administration of the extract to OVX rats suppressed the body weight gain. After 7 weeks, the administration of the extract to the OVX group reduced increases in both serum total cholesterols and high-density lipoprotein (HDL) cholesterols. It also normalized the decrease of triglyceride level in the OVX group. The ovariectomy decreased the tibial bone mineral density (BMD) by 19%, and the administration of the extract to OVX rats did not inhibit this decrease. These results suggest that a dietary supplement of chlorella growth factor may be useful to control the body weight and improve lipid metabolism of menopausal women.

Accumulation of astaxanthin and lutein in Chlorella zofingiensis (Chlorophyta).
Appl Microbiol Biotechnol. 2004 Jun;64(6):848-54. Epub 2003 Dec 20.
When grown photoautotrophically, Chlorella zofingiensis strain CCAP 211/14 accumulates a significant amount of valuable carotenoids, namely astaxanthin and lutein, of increasing demand for use as feed additives in fish and poultry farming, as colorants in food, and in health care products.

Attenuating effect of chlorella supplementation on oxidative stress and NFkappaB activation in peritoneal macrophages and liver of C57BL/6 mice fed on an atherogenic diet.
Biosci Biotechnol Biochem. 2003 Oct;67(10):2083-90.
This study was designed to investigate whether chlorella supplementation may ameliorate oxidative stress and nuclear factor kappa B (NFkappaB) activation in peritoneal macrophages and liver of C57BL/6 mice fed on an atherogenic diet. These results suggest that chlorella supplementation may attenuate oxidative stress by reducing reactive oxygen production and increasing antioxidative processes, thus suppressing inflammatory mediator activation in peritoneal macrophages and liver.

Antioxidant and anti-cataract effects of Chlorella on rats with streptozotocin-induced diabetes.
J Nutr Sci Vitaminol (Tokyo). 2003 Oct;49(5):334-9.
The antioxidant activities of Chlorella in vitro and in vivo were investigated. Chlorella showed a strong antioxidant effect compared to various vegetables. To evaluate the antioxidant and anti-cataract effects in vivo, a 7.3% Chlorella powder was fed to rats with streptozotocin-induced diabetes for 11 wk. At the end of the experiment, Chlorella had decreased the blood glycated hemoglobin (hemoglobin A1c) and serum cholesterol levels significantly, however, it had not affected the serum glucose concentration. The serum lipid peroxide value (TBARS value) in the rats fed Chlorella was lower than that of the control rats. In the liver and kidney, Chlorella also reduced chemiluminescent intensities. In addition, it delayed the development of lens opacities. The lens lipid peroxide content of the rats fed Chlorella was lower than that of the control rats, however the differences were not significant. These results indicate that Chlorella has antioxidant activity and may be beneficial for the prevention of diabetic complications such as cataracts.

Safety and immunoenhancing effect of a Chlorella-derived dietary supplement in healthy adults undergoing influenza vaccination: randomized, double-blind, placebo-controlled trial.
CMAJ. 2003 Jul 22;169(2):111-7.
Enhancement of immune function has been claimed as a benefit of some natural health products, although few have been subjected to randomized clinical trials. We evaluated the effect of an oral dietary supplement derived from the edible microalga Chlorella pyrenoidosa on immune response after influenza vaccination. We conducted a randomized, double-blind, placebo-controlled community-based clinical trial in a convenience sample of 124 healthy adults at least 50 years of age randomly assigned to receive the study product (200 or 400 mg of a Chlorella-derived dietary supplement) or placebo. Participants took the study product or placebo once daily for 28 days. On day 21, we administered a single dose of a licensed trivalent, inactivated influenza vaccine. We obtained serum specimens to measure hemagglutination inhibition titres before and 7 and 21 days after vaccination. The primary immunological outcomes were the proportion of participants with a 4-fold or greater increase in antibodies and geometric mean antibody titres after vaccination; the proportion of participants reporting adverse events during therapy was the safety outcome. A total of 117 (94%) participants completed all aspects of the study. There were no differences in the proportions of recipients of 200 or 400 mg of the Chlorella -derived dietary supplement or placebo who achieved at least a 4-fold increase in antibodies (proportions for the 3 virus strains ranged from 17% to 28% for the 200-mg group, from 11% to 22% for the 400-mg group and from 19% to 21% for the placebo group. Reports of adverse events were similar for recipients of the supplement and placebo, except with regard to fatigue, which was reported more frequently by recipients of 200 mg of the supplement (18/41 or 44%) than by those who received 400 mg of the supplement or placebo. Recipients of 400 mg of the chlorella supplement who were 55 years of age or younger had significantly higher geometric mean antibody titres against influenza A/New Caledonia 21 days after vaccination and against B/Yamanashi 7 days after vaccination; the trends were nonsignificant for titres against A/Panama. We also observed similar increases for the proportions of subjects with a 2-fold or greater or a 4-fold or greater increase in antibodies. The Chlorella derived dietary supplement did not have any effect in increasing the antibody response to influenza vaccine in the overall study population, although there was an increase in antibody response among participants aged 50-55 years. Adverse events were similar among those receiving the supplement and the placebo.

A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa in the treatment of fibromyalgia, hypertension, and ulcerative colitis.
Altern Ther Health Med. 2001 May-Jun;7(3):79-91.
Merchant RE, Andre CA.
It has been suggested that the consumption of natural "whole foods" rich in macronutrients has many healthful benefits for those who otherwise ingest a normal, nonvegetarian diet. One example is dietary supplements derived from Chlorella pyrenoidosa, a unicellular fresh water green alga rich in proteins, vitamins, and minerals. To find evidence of the potential of chlorella dietary supplements to relieve signs and symptoms, improve quality of life, and normalize body functions in people with chronic illnesses, specifically fibromyalgia, hypertension, and ulcerative colitis. Fifty-five subjects with fibromyalgia, 33 with hypertension, and 9 with ulcerative colitis. Subjects consumed 10 g of pure chlorella in tablet form and 100 mL of a liquid containing an extract of chlorella each day for 2 or 3 months. For fibromyalgia patients, assessments of pain and overall quality of life. For hypertensive patients, measurements of sitting diastolic blood pressure and serum lipid levels. For patients with ulcerative colitis, determination of state of disease using the Disease Activity Index. Daily dietary supplementation with chlorella may reduce high blood pressure, lower serum cholesterol levels, accelerate wound healing, and enhance immune functions. The potential of chlorella to relieve symptoms, improve quality of life, and normalize body functions in patients with fibromyalgia, hypertension, or ulcerative colitis suggests that larger, more comprehensive clinical trials of chlorella are warranted.

Nutritional supplementation with Chlorella pyrenoidosa for patients with fibromyalgia syndrome: a pilot study.
Phytother Res. 2000 May;14(3):167-73.
Fibromyalgia syndrome is a common, chronic musculoskeletal disorder of unknown aetiology. While available therapy is often disappointing, most patients can be helped with a combination of medication, exercise and maintenance of a regular sleep schedule. The objective of the present study was to determine if adding nutritional supplements derived from the unicellular green alga, Chlorella pyrenoidosa, produced any improvements in the clinical and functional status in patients with moderately severe symptoms of fibromyalgia syndrome. Eligible patients had 2+ palpable tenderness at 11 or more of 18 defined tender points and had a tender point index (TPI) of at least 22. Each day for 2 months, participants consumed two commercially available Chlorella-based products, 10 g of 'Sun Chlorella' tablets and 100 mL of liquid 'Wakasa Gold'. Any amelioration of symptoms was validated and quantified using semi-objective and subjective outcome measures systematically administered at clinic visits on days 0, 30 and 60 of the diet therapy. Eighteen of the 20 patients enrolled completed the 2 month trial. The average TPI for the group which at onset was 32, decreased to a mean of 25 after 2 months. This decrease was statistically significant, representing a 22% decrease in pain intensity. Blood samples taken on each occasion indicated no significant alterations in serum chemistries, formed elements, and circulating lymphocyte subsets. Compilations of the results of patient interviews and self-assessment questionnaires revealed that seven patients felt that the dietary supplement had improved their fibromyalgia symptoms, while six thought they had experienced no change, and five believed the symptoms had worsened over the time of the trial. The results of this pilot study suggest that dietary Chlorella supplementation may help relieve the symptoms of fibromyalgia in some patients and that a larger, more comprehensive double-blind, placebo-controlled clinical trial in these patients is warranted.

There are various chlorella products on the market, including Sun Chlorella. I am not familiar with the different brands of chlorella and thus do not know if Sun Chlorella is better than other brands.

Two New Age foods which contain high concentrations of whole food nutrients are the single-celled microalgae Chlorella and Spirulina. Chlorella and spirulina are accepted as functional foods, which are defined as products derived from natural sources, whose consumption is likely to benefit human health.

Chlorella supplement questions
Q. I read somewhere that chlorella removes toxins from the body. Is that true? Also, I read that one needs to check their blood iron level before taking chlorella.
   A. When people talk in such vague terms as 'toxins,' it makes me think that either they do not understand the complexity of the human body, or they are just scammers, trying to hype their product. I have not seen any studies where chlorella was found to remove 'toxins' from the body. How are these 'toxins' defined, anyway?
    It makes no sense to me that one has to check their iron level before taking chlorella. It's like saying one has to check their iron level before eating meat products. There are several milligrams of iron in a few ounces of meat. Three capsules of chlorella will have less than one mg of iron. Unless you plan to take half a bottle of chlorella capsules a day for months and years, forget about the silly advice of checking iron levels.

Q. Dear Dr. Sahelian: Since you are a respected authority whose input and knowledge I respect, I wanted to ask: In your opinion, does chlorella have any value as a memory enhancement supplement? The flyer from Sun Chlorella claims that a study where seniors took10 a day of their Sun Chlorella pills, in addition to the liquid extract, proved that it has memory enhancing properties. Have you had any experience with Sun Chlorella? I think its probably a pretty good detoxifier. But I've never heard you mention it. I love the products you formulate and have just finished reading your Mind Boosters book. Thank you for your time.
   A. We have searched Medline and could not find studies with Sun Chlorella and memory. Even if there were one study that showed some benefit, it would pale in comparison to the many studies done with other brain nutrients that are discussed in the Mind Boosters book. Chlorella, in moderation, appears to be a healthy addition to one's diet and supplement intake, however it is one of countless other beneficial supplements that are available.

Q. I am a healthy 19 year old who participates in sports including lacrosse and kung fu. I have recently been introduced to the health benefits of chlorella and spirulina, but I'm on a student's budget (one who's putting himself through a big university) and even though I'd like to take both, I have to choose. I was just wondering if there are certain reasons why I should take one over the other (spirulina versus chlorella).
   A. I am a believer in ingesting a variety of supplements rather than the same one(s) all the time. As such it may be a good idea to take spirulina first, once the bottle is finished to take a week off, and then take a chlorella supplement. It is a good idea to take breaks in between.

Chlorella side effects testimonials
Q. I started taking a chlorella supplement several weeks ago. I did not take them everyday. Last Monday I took Chlorella about an hour after I ate lunch. Within 3 hours I had an upset stomach and threw up several time that night. The next day I was alright. I did not take chlorella for the rest of the week due to I thought that it may have something to do with my sickness. Yesterday, a week later I decided to try chlorella again. This time I took it right after I ate. within in three hours I was violently sick. I was throwing up every 2 to three seconds. It was so bad I got dehydrated within an hour and was so disoriented that an ambulance had to pick me up to take me to the Hospital, By this time the Paramedics said I was throwing up a lot of bile. The doctors at the emergency room told me that it was more likely a reaction to the chlorella. Has anyone else had these kind of side affects? I do not even take the complete recommended dosage. What could have caused such a reaction. I have had stomach viruses before. This was the worst thing that I have ever had. I thought I was dying. How can something that is suppose to be good for you cause such a reaction?
   A. This is the first we have heard of a chlorella supplement causing this side effect. What brand was it, and was it mixed with other herbs or ingredients? Perhaps this particular batch was contaminated? It's best to contact the manufacturer who made this product. What brand was it? Were there other herbs in it?
      Q. The brand is Source Naturals Yaeyama Chlorella. It had just vitamins in it and mixed carotenoids.
          A. Since this first report from 2006, we have had several other chlorella side effect emails.

Q. I read the posting above regarding chlorella side effects and this happened to me as well when I took a chlorella supplement. I tried it on two different occasions and vomited for a least an hour after taking the chlorella supplements. I thought that I was the only one who had this experience because I hadn't seen any comment or questions like this before concerning chlorella pills. I'm quite sure there are several other people who have had this experience with chlorella pills.
   A. This is the second report we have had regarding vomiting side effect after taking chlorella supplements.

Q. I was reading your article on chlorella supplement and was interested to see that more than one person has had a nasty experience after ingesting this chlorella product. I decided to buy some about a month ago and took it in powder form for about 2 weeks. It seemed to agree with me ok, then one day I took it and within one hour I was experiencing the worst case of what felt like food poisoning you can ever imagine. Severe vomiting and diarrhea for several hours. I waited about a week to try again( not believing it could possibly be this wonderful food supplement that I was so impressed by initially) and sure enough the same thing happened. Still, I was undaunted and a week later I tried again but this time I took only 1/8th of a dose. Within one hour once again I was vomiting etc. and the day was ruined due to the fatigue of just getting it out of my system. I am stymied by this and now I'm concerned about what might be causing me to reject it. I have no known diseases or conditions. The chlorella product I took is reputable (Sequel) and has been stored properly. I ate only very benign foods at the time of ingestion and felt fine 'til after it was taken.

I just wanted to add my two cents to the issue of immediate sickness and side effect after taking chlorella supplement. I was reading your chlorella supplement questions site, and noted a couple of people had been violently ill when taking it. This has also happened to me, more than once first when taking a chlorella supplement prescribed by my naturopath and then yesterday, July 2008) when unknowingly drinking a fruit smoothie that contained chlorella. The sickness was debilitating vomiting, diarrhea, etc. and left me on the bathroom floor for four hours. Someone should do chlorella studies on this effect, as it appears I’m not the only one.
    We have had several chlorella side effects reported in terms of gastrointestinal upset.

I saw on your section on chlorella about how someone vomited when they took chlorella. In the past I was able to take it with no problem (NOW chlorella powder). But when I tried it a few weeks later, I vomited all day and was very, very sick. Then I tried it again about a week later and the same thing happened. I don't know if I became allergic to it, or what, but I won't take any type of chlorella now.

I just want to report vomiting violently several hours after taking chlorella supplements - this happened two times and I will never use it again. As in one of the comments on your site an ambulance was called one time. In my experience the chlorella applies itself systemically - I felt sensations from the head to the feet. It also moves one into an altered state of consciousness, the kind of state one enters any time one is quite ill. The brand I used was BioPure. I had another brand a while back and never had any problem with it.

I am witting you to report to you how very ill I became after taking chlorella supplement. The first time I took it the response was delayed (24-48 hours, after I first started). The next time, I tried it, it was only a matter of 4 hours or so, before I was violently vomiting. It took about 24 hours to recover, each time.

I read your post on the chlorella page and The last few were all saying they got sick. I have been taking chlorella for years along with my wife, my two brothers, their wives, my parents and at least 20 friends and acquaintances. No body I know has ever been sick. Since chlorella and spirulina are a food, not supplements, (there is nothing added to pure chlorella and spirulina), that's like trying to say I vomit violently from eating green beans. I know that the drug cartels (prescription drugs that is) go to great lengths to suppress anything like chlorella and spirulina as many people find it does make them very healthy. Speaking for myself and all the people I know, it does make a huge difference in our life and health. Now I did do quite a bit of research on chlorella and did find that there are good manufactures and ones you really should stay away from because of contaminates in their product. My wife suffers from migraines. After taking chlorella and spurulina (10 grams a day each) she had not suffered a disabling migraine (it used to happen at least once a month). Now she may get headaches but they are handled with Tylenol and such. Coincidence? Maybe but I think not. She stopped taking this stuff for about a month and suffered a disabling migraine for the firs time in two years. I told her to get back into the routine and she has been fine since. Anyway, I took the time to write this because I really have seen the benefits of chlorella and spurulina.

 I have about a tablespoon of chlorella powder everyday. I had previously read that it's a "food" and that you can't eat too much. Now I've seen warnings on another health website that over-use of chlorella can lead to excessively high iron levels.
    As with most supplements, it is a good idea to take breaks from use.

I was reading your section on chlorella and saw the abundance of reader comments on several reactions after ingesting chlorella. I also noticed the absence in your comments and research citations of the profound role of chlorella in heavy metal chelation. Chlorella is an essential oral chelator. There is much research on this. It would be a great service to readers if this could be addressed on your site and research could be posted. I think that the reactions people were experiencing have to do with the heavy metal toxic burden being mobilized and reabsorbed or redistribution. I personally experienced a difficult reaction to chlorella - similar to what other readers described - when taking it for heavy metal chelation. I have read that higher doses should be taken in such cases, as more chlorella is needed to sufficiently bind to the metals it mobilizes.
    I have not seen human studies regarding the role of this supplement in terms of chelating heavy metals. Some people think such reactions are due to chelation, but that may not necessarily be so. I question the wisdom of taking more in such cases of getting these unpleasant reactions or side effects.

More information
Chlorella (Chlorella pyrenoidosa), one of the oldest foods on the planet, is a single-celled plant that grows in fresh water and is about the same size as a human blood cell. Chlorella is a green algae, drawing its color from an unusually high amount of chlorophyll (more than any other known plant!). It is grown commercially on water farms, where pure water, clean air, and bright sunlight encourage growth, and special centrifuge equipment is used for harvest. It multiplies quickly, with a complete reproductive cycle every 20 hours.