Chlorella is a type of algae that grows in fresh water. It's sometimes called seaweed. It's used for nutrition and as medicine.

Chlorella is a good source of protein, fats, carbohydrates, fiber, chlorophyll, vitamins, and minerals. Most of the chlorella that is available in the U.S. is grown in Japan or Taiwan. It's made into tablets and liquid extracts.

Chlorella is used to prevent low levels of iron during pregnancy. It is also used for depression, menstrual cramps, fibromyalgia, high cholesterol, and other conditions.

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.

They include:

• Protein: Chlorella is 50–60% protein. What’s more, it’s a complete protein source, meaning it contains all nine essential amino acids.
• Vitamin B12: Some chlorella varieties may also contain vitamin B12, but more studies are needed.
• 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 
• Other antioxidants: These tiny green cells provide a wide range of antioxidants.
• Other vitamins and minerals: Chlorella provides small amounts of magnesium, zinc, copper, potassium, calcium, folic acid and other B vitamins.
• Omega-3s: As with other algae, chlorella contains some omega-3s. Just 3 grams of chlorella delivers 100 mg of omega-3s.
• 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.

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. 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.

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.

Several studies have suggested that chlorella supplements may help lower cholesterol. 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.

Chlorella’s content of the following may help improve blood lipid levels:

• Niacin: A B vitamin known to lower cholesterol 
• Fiber: A cholesterol-lowering agent
• Carotenoids: Have been shown to naturally lower cholesterol
• Antioxidants: Help prevent the oxidation of LDL cholesterol, which is known to contribute to heart disease 

Chlorella contains several compounds that are considered antioxidants, including chlorophyll, vitamin C, beta-carotene, lycopene and lutein. These antioxidants can help fight many chronic diseases. Some of these antioxidants seem to reduce the production of advanced glycation end products (AGEs), which drive many of the complications of diabetes 

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. 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. One theory to explain this is that some of chlorella’s nutrients, including arginine, potassium, calcium and omega-3s, help protect arteries from hardening.

Some research shows that chlorella may help lower blood sugar levels. 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. Other studies have shown that supplementing with chlorella improves blood sugar control and increases insulin sensitivity in patients with non-alcoholic fatty liver disease.

Other Potential Benefits

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.
• 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.
• 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 

Potential Concerns

There are a few things to keep in mind when considering chlorella supplements:

• Possible side effects: Some people have experienced nausea and abdominal discomfort.
• 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.
• Immune effects: Since chlorella affects the immune system, it may not be appropriate for people with immunodeficiency or on immune system medications.

Furthermore, it’s important to keep in mind that dietary supplements may interact with some medications.

While chlorella is generally recognized as safe and few side effects have been reported, it might not be appropriate for everyone..

How to Supplement With Chlorella

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.

Some studies have found benefits with 1.2 grams per day, while others looked at doses of 5–10 grams per day 

Most supplements indicate a daily dosage of 2–3 grams, which seems about right considering the research.