Move over spirulina, there's a new algae in town — chlorella. This nutrient-dense algae has been receiving a lot of buzz for its health benefits.
Furthermore, as a supplement, it has shown promise in improving cholesterol levels and ridding the body of toxins.
This article tells you all you need to know about chlorella, including what it is, the research behind its health claims and how to take it as a supplement.
Chlorella is a single-celled, green freshwater algae (1).
There are over 30 different species, but two types — Chlorella vulgaris and Chlorella pyrenoidosa — are most commonly used in research (2).
Because chlorella has a hard cell wall that humans cannot digest, you must take it as a supplement to reap its benefits (3).
It's available in capsule, tablet, powder and extract form (3).
In addition to being used as a nutritional supplement, chlorella is also used as a biodiesel fuel (4).
Interestingly, studies indicate it can have many health benefits. Here are 9 of them.
Chlorella's impressive nutritional profile has led some to call it a "super food." While its exact nutrient content depends on growing conditions, the species used and how supplements are processed, it's clear it packs several beneficial nutrients.
- Protein: Chlorella is 50–60% protein. What's more, it's a complete protein source, meaning it contains all nine essential amino acids (3, 5).
- Vitamin B12: Some chlorella varieties may also contain vitamin B12, but more studies are needed (6).
- Iron and vitamin C: Chlorella can be a good source of iron. Depending on the supplement, it may provide anywhere from 6–40% of your daily need. It's also an excellent source of vitamin C, which helps you absorb iron (1, 3, 7).
- Other antioxidants: These tiny green cells provide a wide range of antioxidants (1, 3).
- Other vitamins and minerals: Chlorella provides small amounts of magnesium, zinc, copper, potassium, calcium, folic acid and other B vitamins (1, 3, 8).
- Omega-3s: As with other algae, chlorella contains some omega-3s. Just 3 grams of chlorella delivers 100 mg of omega-3s (8).
- Fiber: In large quantities, chlorella can be a good source of fiber. However, most supplements don't provide even 1 gram of fiber per dose (1, 8).
Summary: Chlorella contains many nutrients, including vitamins, minerals, antioxidants and omega-3 fats. Exact quantities may differ among brands.
Chlorella has gotten some buzz for its ability to help the body "detox." In fact, animal studies indicate that it's effective at helping remove heavy metals and other harmful compounds from the body (9, 10, 11).
Heavy metals include some elements that are essential in small amounts, such as iron and copper, but these and other heavy metals like cadmium and lead can be toxic in larger amounts.
While it's rare for people to have dangerous levels of heavy metals in their system, people can get exposed to heavy metals through pollution or certain jobs such as mining (12).
In animals, algae, including chlorella, has been found to weaken the heavy metal toxicity of the liver, brain and kidneys (13).
Furthermore, chlorella has been shown to help lower the amount of other harmful chemicals that are sometimes found in food. One of these is dioxin, a hormone disruptor that can contaminate animals in the food supply (14, 15).
Based on this evidence, it seems that chlorella could help enhance your body's natural ability to clear toxins.
Summary: Chlorella may help the body detox by binding to heavy metals and other toxins.
Your immune system helps keep you healthy by fighting off infections.
It's a complex system made up of multiple mechanisms and cells that get into gear when an invader enters your body.
Chlorella has been found to enhance the immune response in both animal and human studies, although the evidence so far is limited.
In one small study, men produced more antibodies when taking chlorella than when they took a placebo. Antibodies help fight foreign invaders in your body, meaning this finding is quite promising (16).
In another small, eight-week study, healthy adults who took chlorella showed markers of increased immune activity (17).
Nevertheless, findings have been mixed, with some studies showing little to no effect.
For instance, one study found that chlorella supplements enhanced immune function in participants aged 50–55, but not those over 55 (18).
So it's possible that chlorella may have immune-boosting effects in some populations and age groups, but not in all. More and larger-scale studies are needed.
Summary: Chlorella may bolster immune function by increasing the activity of various parts of the immune system.
Specifically, several studies have shown that taking 5–10 grams of chlorella daily lowered total and LDL cholesterol and triglycerides in people with high blood pressure and/or slightly elevated cholesterol (5, 19).
Chlorella's content of the following may help improve blood lipid levels:
- Niacin: A B vitamin known to lower cholesterol (1, 21).
- Fiber: A cholesterol-lowering agent (1, 22).
- Carotenoids: Have been shown to naturally lower cholesterol (19, 23, 24).
- Antioxidants: Help prevent the oxidation of LDL cholesterol, which is known to contribute to heart disease (25).
Summary: The nutrients found in chlorella, including niacin, fiber, carotenoids and antioxidants, may help lower your cholesterol levels.
These antioxidants can help fight many chronic diseases (26).
Although much of this research is promising, it is still preliminary.
Summary: Chlorella's antioxidant content may provide some protection against chronic disease, but more human studies are needed to confirm this.
Chlorella supplements could help promote heart and kidney health, which is essential for normal blood pressure.
In one study, people with mildly high blood pressure took four grams of chlorella daily for 12 weeks.
By the end, these people had lower blood pressure readings than participants who took the placebo (31).
Another small study in healthy men showed that taking chlorella supplements was linked to less stiffness of the arteries, a factor that affects blood pressure (32).
Summary: Some research on chlorella has pointed to a blood pressure-lowering effect. Many of its nutrients have been shown to prevent arteries from hardening.
One study found that taking chlorella for 12 weeks lowered fasting blood sugar levels in both healthy individuals and those at high risk of lifestyle-related diseases (20).
There isn't enough research yet to say that you should take chlorella to manage blood sugar, but it may help when combined with other therapies.
Summary: Taking chlorella supplements may help lower blood sugar levels and increase insulin sensitivity.
One study found that chlorella supplements improved antioxidant status in COPD patients, but that didn't translate into any improvements in breathing capability (40).
More studies are needed to determine its true effect on respiratory conditions, but chlorella might help with inflammation.
Summary: The antioxidants in chlorella may have anti-inflammatory effects, which can possibly improve asthma and other respiratory diseases.
Only one study has looked at chlorella's effect on aerobic endurance, but it showed a positive effect.
Researchers gave a group of young adults six grams of chlorella or a placebo daily for four weeks.
At the end of the study, the chlorella group showed a significantly improved ability to saturate their lungs with oxygen, which is a measure of endurance. The placebo group did not experience any changes in endurance (41).
This effect may be due to chlorella's branched-chain amino acid content.Branched-chain amino acids are a collection of three amino acids that have been found to improve aerobic performance in various studies (42, 43).
Summary: Chlorella may improve your aerobic performance, although scientific support for this benefit is limited.
Many other possible benefits have been proposed, but there's little research to support these claims.
Here are some of the main health claims:
- Promotes eye health: Chlorella contains lutein and zeaxanthin, two carotenoids that protect the eye and lower the risk of macular degeneration (44, 45, 46).
- Supports liver health: Chlorella supplements have been shown to improve markers of liver health in people with liver disease. However, it's not clear whether there's a benefit for healthy people (34, 35, 36, 47).
- Improved digestion: Many sources claim chlorella eases digestion and reduces bloating. However, no studies have assessed these proposed benefits.
- Relieves PMS: Anecdotal evidence says that chlorella can relieve symptoms of premenstrual syndrome (PMS). It could be a stretch, but chlorella contains calcium and B-vitamins, both of which have been shown to reduce PMS (48, 49).
Summary: Chlorella has been claimed to improve energy levels, liver health, digestion and symptoms of PMS. Nevertheless, scientific evidence is currently lacking to directly support these claims.
However, there are a few things to keep in mind when considering chlorella supplements:
- Possible side effects: Some people have experienced nausea and abdominal discomfort (51).
- Lack of regulation: Some countries, including the US, do not regulate supplements, and you can't be sure you're getting what the label says.
- Inconsistent products: The nutrition content of chlorella supplements may vary, depending on the algae species, growing conditions and processing (52, 53).
- Immune effects: Since chlorella affects the immune system, it may not be appropriate for people with immunodeficiency or on immune system medications.
While chlorella is generally recognized as safe and few side effects have been reported, it might not be appropriate for everyone.
Summary: For most people, taking chlorella supplements doesn't seem to pose any serious risks.
The current scientific literature on chlorella doesn't specify a specific dosage.
This is because there's insufficient evidence to determine the amount needed to see therapeutic effects (1).
Most supplements indicate a daily dosage of 2–3 grams, which seems about right considering the research. Moreover, it's important to find a quality supplement. The best way to do this is to look for one that has a quality assurance seal from third-party testing.
Additionally, some product descriptions mention testing for quality assurance, as well as the source and growing conditions of the chlorella.
Try to find chlorella supplements from a supplement brand you trust.
Summary: Look for a quality assurance seal to ensure you're getting what you pay for. The dose of 2–3 grams indicated by most supplements seems appropriate, given the doses used in studies.
Chlorella is a type of algae that packs a big nutrient punch, as it's a good source of several vitamins, minerals and antioxidants.
In fact, emerging research shows that it could help shuttle toxins out of your body and improve cholesterol and blood sugar levels, among other health benefits.
For now, there doesn't seem to be any harm in taking chlorella supplements, and they could support your health.