Evidence Level
Limited
2 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

Chlorella is a single-celled freshwater green algae packed with chlorophyll, complete protein (60% by weight), vitamins, minerals, and unique compounds including Chlorella Growth Factor (CGF). Widely paired with spirulina in greens formulas, chlorella is particularly valued for its heavy metal detoxification properties, immune modulation, and nutritional density, with a cell wall that must be cracked for bioavailability.

Studied Dose 3–10 g/day dried powder (tablets or powder); cracked cell wall preparation essential
Active Compound Chlorophyll and Chlorella Growth Factor (CGF) — cracked/broken cell wall chlorella required for bioavailability

Heavy metal and toxin binding

Chlorella's cell wall and unique binding proteins chelate heavy metals (mercury, lead, cadmium, arsenic) and persistent organic pollutants in the GI tract and bloodstream, facilitating their excretion. Clinical studies in Japanese populations show chlorella supplementation reduces blood mercury and dioxin levels.

Immune system modulation

Chlorella Growth Factor (CGF) — a unique nucleotide/peptide complex found only in chlorella — stimulates NK cell activity, macrophage function, and interferon production. RCTs show enhanced immune response to influenza vaccination and reduced incidence of upper respiratory infections.

Lipid and blood sugar regulation

Multiple RCTs show chlorella significantly reduces total cholesterol, LDL, and triglycerides, while improving fasting blood glucose and insulin resistance markers in adults with metabolic syndrome and non-alcoholic fatty liver disease.

Nutritional density and greens support

Chlorella provides complete protein with all essential amino acids, vitamins B1, B2, B3, B6, B12, vitamin C, iron, magnesium, and zinc in bioavailable forms. As a whole-food supplement, it contributes meaningful micronutrient intake alongside its functional effects.

1

Cell wall binding and chelation of heavy metals

Chlorella's cell wall contains sporopollenin-like compounds and unique binding proteins that form stable complexes with heavy metal ions (Hg2+, Pb2+, Cd2+) and organochlorine compounds. These complexes pass through the intestine without absorption and are excreted in feces, reducing systemic heavy metal burden.

2

Chlorella Growth Factor immunostimulation

CGF — a water-soluble nucleotide-peptide extract from chlorella — directly stimulates NK cell cytotoxicity, macrophage phagocytosis, and secretory IgA production. CGF also supports gut barrier function and beneficial microbiome populations, contributing to systemic immune benefits.

3

Chlorophyll and antioxidant activity

Chlorella's extremely high chlorophyll content (2–3% by dry weight — among the highest of any supplement) acts as an antioxidant, promotes alkalinity, and may bind carcinogens and heterocyclic amines from cooked meat in the GI tract, potentially reducing their systemic absorption.

1
Chlorella and Blood Mercury Reduction in Japanese Adults
PubMed

RCT examining chlorella tablet supplementation effects on blood and urinary mercury levels in adults with high fish consumption in Japan.

Japanese adults with high seafood consumption. Supplementation study.

Chlorella supplementation significantly reduced blood mercury levels vs. placebo. Also reduced blood dioxin and furan levels. Supports use in populations with high environmental heavy metal exposure.

2
Chlorella and Lipid Profiles in Metabolic Syndrome — RCT
PubMed

RCT of chlorella supplementation (5 g/day) vs. placebo in adults with metabolic syndrome for 12 weeks.

Adults with metabolic syndrome. 12-week intervention.

Significant reductions in total cholesterol, LDL, triglycerides, and fasting glucose. Improved insulin resistance index. Liver enzyme levels reduced. Well-tolerated.

Common Potential side effects

GI discomfort (bloating, gas, loose stools) common during first week — usually resolves
Green discoloration of stools (harmless — chlorophyll)
Photosensitivity (sunburn sensitivity) reported rarely with high doses
Avoid in iodine-sensitive individuals — chlorella contains iodine

Important Drug interactions

Anticoagulants (warfarin) — chlorella contains vitamin K; monitor INR if adding chlorella supplementation
Immunosuppressants — chlorella stimulates immune function; may counteract cyclosporine or tacrolimus
Heavy metal chelation therapy — may interfere with pharmaceutical chelation timing; separate doses by several hours