The medicinal properties and nutritional value of Chlorella can help shield the heart, brain, liver, and more. Asian traditions have used this microalga for centuries, and modern science now brings it to the west. Read on to learn about Chlorella health benefits, potential side effects, and user reviews.
Chlorella is a type of single-celled green alga (microalga) that is usually found in freshwater environments. Some species of this microalga have myriad health benefits while being packed with essential nutrients [1, 2].
The interest in Chlorella production began in the 1960s when a Japanese company started to culture it on a massive scale, and by 1980 the production spread in Asia, reaching more than 1,000 kg of produced microalga (mainly Chlorella) per month .
Today, Chlorella is being used in Japan, the USA, Europe, and other countries. In East Asia, it is ingested with rice, tea, and pancakes. Furthermore, Chlorella is sold extensively as a supplement or nutraceutical product [4, 5].
Due to its high concentration of protein (50%), Chlorella is a good source of the essential amino acids required for our nutrition .
- Reduced blood sugar and cholesterol
- Protects the heart and liver
- Prevents anemia
- Supports detox
- Combats oxidative stress
- May improve mental health
- May enhance physical performance
- Many benefits lack clinical evidence
- May cause digestive upset and dizziness
- Interacts with blood thinners
Chlorella’s main constituent is the Chlorella Growth Factor (CGF), an extract composed of diverse substances including essential amino acids, peptides, proteins, vitamins, sugars, and nucleic acids .
- Protein (Chlorella is 50% protein, and a great source of amino acids, including alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, and valine)
- Vitamins (vitamin B1/thiamine, B2/riboflavin, B3/niacin, B5/pantothenic acid, B6/pyridoxine, B7/biotin, B9/folic acid, B12/cobalamin, and vitamin C)
- Para-aminobenzoic acid
- Minerals (including phosphorus, potassium, magnesium, calcium, iron, copper, zinc, manganese, and iodine)
- Linoleic acid
- Omega-3 fatty acids
Lycopene isolated from Chlorella marina lowered inflammatory enzymes (COX, LOX, and MPO), improved inflammatory blood markers (CRP), and markedly decreased swelling in the paw and joints of rats with arthritis. It had a more potent activity than tomato lycopene .
Chlorella ellipsoidea reduced the activation of nuclear factor kappa B (NFκB), thus lowering inflammation in a type of white blood cell (macrophage) of mice fed with a high-fat and high-cholesterol diet .
A Chlorella component (Chlorella 11-peptide) suppressed the inflammatory cytokine TNF-alpha and an inflammatory mediator (nitric oxide) in both injured rats and white blood cell cultures (macrophages) .
A meta-analysis of 19 randomized control trials with 797 subjects revealed that Chlorella significantly decreases fasting blood glucose .
In a placebo-controlled study with 57 borderline diabetic patients, Chlorella tablets for 12 weeks alleviated some features of type 2 diabetes by decreasing resistin production and increasing adiponectin receptor (ADIPOR1) .
Chlorella (C. pyrenoidosa) dried powder decreased the levels of cholesterol (LDL and total cholesterol) and triglycerides (TG) and raised levels of good cholesterol (HDL) in animals (rats and hamsters) on a high-fat diet .
A study performed in 80 individuals (with normal-high levels of blood pressure and borderline hypertension), showed that those who consumed GABA-rich Chlorella tablets for 12 weeks reduced their blood pressure significantly .
A meta-analysis of 19 randomized control trials with 797 subjects revealed that Chlorella significantly decreased systolic and diastolic blood pressure .
Taken together, the effects of Chlorella on blood sugar, cholesterol, and blood pressure indicate its potential to prevent heart disease, but clinical trials should investigate this further.
Intense exercise can weaken the immune system. In a placebo-controlled study performed in 10 female athletes, 5 weeks of Chlorella supplementation prevented the decrease in immune function (measured by salivary immunoglobulin A) during a training camp .
Another study of 15 men, revealed that salivary IgA was increased in participants when they ingested Chlorella tablets for 4 weeks .
A study of 35 pregnant women showed increased IgA levels in the breast milk of women that consumed Chlorella for 6 months before giving birth. Higher levels of IgA in breast milk helps reduce the risk of infection in nursing infants .
In mice, Chlorella counteracted the effect of a chemotherapeutic drug (Cyclophosphamide) that suppresses the immune system by recovering NK cell function and increasing Th1 cytokines (IL-2, IL-12, TNF-a, IFN-y) .
In a study performed in 38 smokers for 6 weeks, Chlorella reduced the levels of malondialdehyde in the blood, a marker of oxidative stress, and increased blood levels of 7 different antioxidant measures :
- Vitamin C
- Vitamin E
- Glutathione (GSH)
- Superoxide dismutase activity (SOD)
- Glutathione peroxidase activity (GPx)
- Catalase activity (CAT)
- Total antioxidant status
Furthermore, another 6-week study with 52 smokers revealed that Chlorella powder increased blood levels of vitamin E (alpha-tocopherol) and vitamin C. It also raised the activity of superoxide dismutase and erythrocyte catalase .
In a 2-month trial performed in 12 elderly subjects, it decreased oxidative damage to red blood cells by reducing phospholipid hydroperoxide (PLOOH) concentrations, thus enhancing their ability to transport oxygen to the brain .
Liver function improved in 60 fatty liver disease (NAFLD) patients who consumed C. vulgaris tablets for 8 weeks .
Another study of 70 fatty liver disease patients showed that Chlorella enhanced patients’ condition by reducing weight and blood glucose levels and decreasing inflammatory indicators (TNF-a and high-sensitivity C-reactive protein) ,
A trial of 6 individuals revealed that Chlorella consumed for 2 weeks decreased urine levels of a cancer-causing heterocyclic amine .
In a study of 35 pregnant women, taking C. pyrenoidosa tablets for 6 months during pregnancy reduced the transfer of dioxins to children through breast milk .
Dioxins are highly toxic, cancer-causing chemicals.
In mice, C. pyrenoidosa accelerated the breakdown of dioxins, preventing their accumulation in the liver .
It had a protective effect against carcinogenic heterocyclic amines in rat colon .
Parachlorella beijerinckii accelerated the excretion of methylmercury and consequently decreased tissue levels of mercury in mice .
Chlorella improved the elimination of radioactive strontium from mice through adsorption in the intestines .
A study in pregnant mice revealed how C. pyrenoidosa suppressed methylmercury transfer to the fetus and reduced its accumulation in the mothers’ brains .
It protected rats against cadmium liver toxicity by decreasing cadmium accumulation and stimulating the expression of metallothioneins in the liver. Metallothioneins are heavy metal-binding proteins found in the circulation and produced by several tissues in the body .
However, in one study, C. vulgaris was unable to increase cadmium excretion in rats fed this heavy metal .
In a study of 70 pregnant women, Chlorella supplementation (6 g daily, from the 12th-18th week of pregnancy) reduced the risk of anemia by 48%, compared to control .
This regiment also reduced leg swelling and urine protein loss but didn’t reduce the risk of gestational hypertension (high blood pressure during pregnancy) .
No valid clinical evidence supports the use of Chlorella for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.
A 14-day study performed in 10 individuals revealed that Chlorella increased aerobic endurance capacity by improving maximum oxygen uptake .
C. vulgaris improved physical stamina in mice .
In rats, Chlorella consumption, combined with high-intensity intermittent exercise, enhanced exercise performance and improved muscle metabolism by increasing the activity of crucial enzymes such as lactate dehydrogenase (LDH) .
A study performed in 125 patients with major depressive disorder showed improvement in depression and anxiety in patients who consumed C. vulgaris tablets in addition to their standard antidepressant medications for 6 weeks. That said, all improvements were subjective .
This result could be explained by the neuroprotective components contained in C. vulgaris (linoleic acid and vitamin B12/methylcobalamin), which have been reported to improve depressive symptoms .
Further research is needed to investigate the potential antidepressant effects of Chlorella.
No clinical evidence supports the use of Chlorella for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies; they should guide further investigational efforts but should not be interpreted as supportive of any health benefit.
C. vulgaris extract improved allergic inflammation in mice by inhibiting IL-5 production (IgE-dependent) and reducing the recruitment of major inflammatory cells to the allergic airways (eosinophils and neutrophils). IL-5 is an important cytokine involved in the development of allergic inflammation .
The findings discussed below stem from animal and cell-based studies only. They should guide further investigation but shouldn’t be interpreted as supportive of the anticancer effects until more research is done. Chlorella supplements aren’t approved for cancer prevention or treatment
Another species of Chlorella (C. sorokiniana), killed human lung cancer cells and reduced tumor growth in mice (by decreasing cell-survival factors Bcl-2, survivin, and XIAP, and increasing cell death causing Bax) .
C. pyrenoidosa improved breast cancer in mice by suppressing its growth .
Lycopene extracted from Chlorella (C. marina) suppressed the growth and induced the cell death of human prostate cancer cells .
On the other hand, a study revealed how C. vulgaris promoted breast cancer growth in mice when given in high doses (200 mg/kg). This may be a consequence of the expression of diverse cytokines that promote tumor growth (IFNy and IL-4 were decreased, while TGFβ1, IL-10, and IL-1b were increased) .
Clinical trials are needed to investigate the potential anticancer effects of Chlorella. At this point, it can’t be recommended for cancer treatment or prevention.
C. vulgaris may have an anti-aging effect because it :
- removes free radicals (due to its high levels of antioxidants)
- inhibits telomere shortening (oxidative-stress-induced DNA damage)
Cells age when the telomeres (ends of chromosomes) are shortened. This happens every time your cells divide, with each round of replication (DNA synthesis). Therefore, increased telomerase activity boosts telomere production and increases the lifespan of cells [63, 64].
Although superoxide dismutase (SOD) is an antioxidant enzyme, it produces hydrogen peroxide that has to be removed by GPx and catalase. C. vulgaris reduced SOD levels in cells and thereby slowed cell aging .
That said, the anti-aging properties of chlorella haven’t yet been tested in clinical trials.
Chlorella (Parachlorella beijerinckii) prevented cognitive decline in mouse models of dementia by reducing oxidative stress and inflammation .
Moreover, the water extract of Chlorella boosted the production of stem cells in the bone marrow and spleen, which increased the survival of mice after being irradiated with gamma rays .
Chlorella improved the condition of mice with muscle atrophy by reducing oxidative stress and decreasing creatine phosphatase levels (a muscle impairment marker); it also helped to maintain the activity of the mitochondrial cytochrome c oxidase .
In another animal trial, it decreased ulcer incidence in stressed rats .
Chlorella minutissima extract increased antioxidant enzymes (GST) while it decreased the activity of enzymes involved in skin disorders (tyrosinase and elastase). This extract could be potentially used in cosmetic products for irritated, reactive, and aging skin .
Another study suggested that some Chlorella extracts have an inhibitory effect on Propionibacterium acnes, a bacterium that has been described as one of the major causes of acne .
Chlorella improved atopic dermatitis symptoms in mice by :
- Reducing white blood cells infiltration into the skin (eosinophils and mast cells)
- Decreasing pro-inflammatory mediators (thymus- and activation-regulated chemokine and macrophage derived-chemokine)
- Decreasing the levels of IL-4 and IFN-y cytokines
Chlorella extract improved skin reconstitution and accelerated wound healing when given to wounded mice at high doses (orally and topically) .
In stroke-prone rats with high blood pressure, Chlorella powder (C. regularis), containing carotenoids and arginine, improved blood vessel function, decreased the incidence of stroke, and increased lifespan .
This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.
- Digestive upset
- Itching and rash
- Muscle pain
Chlorella is possibly safe during pregnancy, but pregnant women should use it only if prescribed by their doctor .
Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let them know about all drugs and supplements you are using or considering.
Some suggest that Chlorella may interfere with immunosuppressive drugs. However, there is no evidence to support this statement .
According to preliminary research, Chlorella increases insulin sensitivity, enhances immune system function, counteracts the effects of free radicals, and decreases blood pressure .
On the other hand, spirulina improves hemoglobin, protein, and vitamin levels in malnourished children, increases immune function, has a great antioxidant capacity, and is a good source of beta-carotene .
Spirulina has a greater quantity of beta-carotene and protein content than Chlorella, whereas Chlorella has a better protein quality for human nutrition .
According to registered data obtained from microalgae consumers, spirulina has a higher rate of adverse events than Chlorella .
Dosage: The recommended daily intake of Chlorella is up to 10 g .
The opinions expressed in this section are solely from the users who may or may not have a medical background. SelfDecode does not endorse any specific product, service, or treatment. Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice because of something you have read on SelfDecode.
One user experienced severe digestive discomfort which they think was caused by too strong detox process. They suggest going slow with Chlorella and gradually working up to higher doses, due to its potent detox properties.
Another user was building up from 1 to 5 tablets per day and reported good detox results with no side effects.
However, one person also experienced severe nausea and vomiting after a few weeks of Chlorella supplementation. The adverse effects disappeared upon the supplement cessation. The same person previously practiced long-term spirulina supplementation with no side effects.