Chlorella is a single-celled freshwater green algae that belongs to the Chlorellaceae family. Naturally found in lakes, rivers, and other aquatic environments, chlorella has become a popular dietary supplement through large-scale cultivation methods.

Research suggests that chlorella supplementation may improve several aspects of health, including reducing low-density lipoprotein (LDL) cholesterol, managing hypertension (high blood pressure), and enhancing antioxidant defenses in the body. These potential benefits make chlorella a notable addition to a wellness-focused lifestyle.

May Reduce Heart Disease Risk Factors

Heart disease is the leading cause of death worldwide, and factors such as elevated blood lipids and high blood pressure significantly increase your risk. Incorporating chlorella supplements may help mitigate these risk factors.

A review of 19 studies including 797 participants found that taking more than 4 grams per day of chlorella for eight weeks or longer significantly decreased LDL cholesterol, total cholesterol, and both systolic and diastolic blood pressure. Improvements were observed in both healthy individuals and those with elevated cholesterol or hypertension.

Chlorella may also reduce fasting blood sugar, further supporting cardiovascular health. Its benefits are partly attributed to the amino acid arginine, which produces nitric oxide (NO). NO widens blood vessels, improving blood flow and supporting blood pressure regulation. Additionally, compounds in chlorella may reduce cholesterol absorption and enhance its excretion, promoting healthier blood lipid profiles.

High in Antioxidants

Chlorella is rich in antioxidant compounds, particularly carotenoids such as lutein, β-carotene, and zeaxanthin. These compounds have strong cellular-protective properties and may help prevent oxidative stress linked to chronic diseases, including cancer and age-related macular degeneration (ARMD).

A small study with 11 participants showed that a single 6 g dose of chlorella significantly increased blood levels of carotenoids for three days. Regular supplementation may therefore support antioxidant defenses and overall health.

May Protect Against Iron Deficiency

Iron deficiency is common, particularly among individuals assigned female at birth and those following plant-based diets. Chlorella is a rich plant-based source of iron, providing 12 mg per 2-teaspoon serving, covering 67% of daily needs.

Studies indicate that chlorella can effectively boost iron levels in those with iron deficiency, including pregnant individuals. It also provides folate, vitamin A, vitamin C, and omega-3 fats, supporting cardiovascular, immune, and overall health.

May Benefit Exercise Performance

Chlorella supplementation may enhance exercise performance by improving oxygen uptake and muscle endurance. Its blood vessel–widening properties increase oxygen delivery to muscles during workouts.

A small study with 20 adults found that taking 6 g of chlorella for two days increased peak oxygen pulse (oxygen consumed per heartbeat) and decreased peak blood lactate concentration during exercise. While promising, larger studies are needed to confirm these findings.

How To Take Chlorella

Chlorella is available in powders, liquids, and tablets. It can be taken alone or as part of multi-supplement formulations, including greens powders that contain spirulina, kale, and spinach.

Dosage: Most studies use 3–10 g per day for 2–3 months. Dosage depends on product type and health goals. Consult a healthcare provider for personalized advice.

Is Chlorella Safe?

Chlorella is generally safe when taken in appropriate doses.

Precautions include:

  • Avoid improperly processed supplements, which may harbor pathogenic bacteria.

  • People with autoimmune diseases (e.g., lupus) should exercise caution due to immune-stimulating effects.

  • Individuals sensitive to iodine may experience allergic reactions.

Potential Drug Interactions

Chlorella may interact with certain medications:

  • Photosensitizing drugs: May increase sun sensitivity.

  • Blood sugar–lowering medications: Could enhance hypoglycemic effects.

  • Blood thinners: High vitamin K content may reduce effectiveness of warfarin (Coumadin).

Always consult a healthcare provider if taking medications.

What To Look For in Chlorella Supplements

Choose supplements from companies adhering to strict safety standards. Look for:

  • Third-party testing for contaminants like heavy metals.

  • Certifications from USP, NSF International, or similar.

  • Transparent ingredient labels, especially in greens powder blends.

Can You Take Too Much Chlorella?

Chlorella is generally safe up to 15 g per day. Start with lower doses to minimize side effects, including abdominal pain, constipation, diarrhea, fatigue, flatulence, sun sensitivity, or discolored stool. Rarely, anaphylaxis may occur.

A Quick Review

Chlorella is a freshwater green algae widely used as a dietary supplement. It may:

  • Improve heart disease risk factors (cholesterol, blood pressure, fasting blood sugar)

  • Boost antioxidant levels

  • Help prevent iron deficiency

  • Enhance exercise performance

Chlorella is generally safe but consult your healthcare provider if you have underlying conditions or take medications.