Compound
    Moderate Evidence

    Chlorella

    Chlorella vulgaris

    TL;DR

    Chlorella is a single-celled green algae rich in chlorophyll, protein and carotenoids. Human trials show modest benefits for blood pressure and possibly lipid and immune markers, but detox claims are overhyped and cell-wall-cracked products are essential for absorption.

    Ideal For

    • People with mildly elevated blood pressure
    • Those wanting a food-based source of B12 (check label for content)

    Avoid If

    • You are on warfarin (vitamin K content is significant and can antagonise)
    • You have had allergic reactions to algae
    • You expect it to chelate heavy metals (unproven in humans)

    Frequently Asked Questions

    Overview

    Chlorella (Chlorella vulgaris/pyrenoidosa) is a freshwater algae with a tough cellulose cell wall that must be mechanically cracked for human digestion. It is a genuine source of bioactive B12 (unlike spirulina), lutein, and chlorophyll. RCT evidence is small but real: a meta-analysis of trials found chlorella supplementation (typically 4-8 g/day) significantly reduced systolic and diastolic blood pressure, with larger effects in hypertensive subjects. Smaller RCTs report improved immune markers (e.g., increased secretory IgA and NK cell activity), modest LDL reductions, and reduced dioxin levels in breast milk in a Japanese cohort. However, most trials are small, short and industry-adjacent. Heavy-metal detox claims rest on animal and in-vitro work; chelation in humans is unproven. Quality control is critical because algae accumulate environmental contaminants.

    How It Works

    • Chlorophyll and carotenoids provide antioxidant capacity
    • GABA and arginine content may contribute to BP reduction
    • Beta-glucans and cell-wall polysaccharides modulate innate immune activity
    • Binds some environmental contaminants in the gut (animal evidence)

    Benefits & Outcomes

    Immune Function

    Immune
    Mixed evidence
    Preliminary

    Small RCTs report that chlorella supplementation (2-5 g/day) increases secretory IgA and NK-cell activity and may reduce cold/flu symptom days, but the trials are small, short, and mostly from single research groups. Immune support is plausible, not proven.

    Health Concerns Addressed

    No linked health concerns yet.

    Supporting Research
    4 studies

    The role of Chlorella and Spirulina as adjuvants of cardiovascular risk factor control: a systematic review and meta-analysis of randomised controlled trials

    Score: 7/10
    2025
    meta_analysis

    Pinto-Leite M, Martins D, Ferreira AC +1 more

    Pooled analyses showed modest improvements in lipid and glycaemic markers, with inconsistent effects on some endpoints.

    View source

    Effect of Chlorella supplementation on cardiovascular risk factors: A meta-analysis of randomized controlled trials

    Score: 7/10
    2018
    meta_analysis
    n=797

    Fallah AA, Sarmast E, Habibian Dehkordi S +4 more

    Chlorella supplementation significantly reduced total cholesterol, LDL cholesterol, systolic and diastolic blood pressure and fasting blood glucose.

    View source

    Effect of supplementation with Chlorella vulgaris on lipid profile in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

    Score: 7/10
    2022
    meta_analysis
    n=797

    Sherafati N, Bideshki MV, Behzadi M +3 more

    Chlorella vulgaris supplementation reduced total cholesterol and LDL cholesterol in adults.

    View source

    Impact of daily Chlorella consumption on serum lipid and carotenoid profiles in mildly hypercholesterolemic adults: a double-blinded, randomized, placebo-controlled study

    Score: 6/10
    2014
    rct
    n=63

    Ryu NH, Lim Y, Park JE +4 more

    Five grams per day of Chlorella for four weeks lowered total cholesterol, LDL cholesterol and triglycerides versus placebo.

    View source

    Safety Information

    Potential Side Effects

    Nausea, green stools, and occasional allergic reactions; photosensitivity reported rarely.

    Contraindications

    Warfarin therapy without INR monitoring; algae allergy.

    Drug Interactions

    • Warfarin (high vitamin K content can reduce efficacy)
    • Immunosuppressants (theoretical)

    Pregnancy & Breastfeeding

    Pregnancy: insufficient_data

    Breastfeeding: insufficient_data

    Dosage Guidelines

    Dosage Used in Studies

    2-8 g

    Best Time to Take

    Divided with meals

    Best Form

    Broken/cracked cell-wall, third-party contaminant tested

    Dosing by Goal

    GoalDoseNotes
    4-8 g/dayMeta-analysis range
    2-5 g/dayCommon trial dose

    Forms Compared

    Required for digestibility; check for contaminant testing

    Convenient; many tablets needed for gram-level doses

    Food & Timing

    With meals to reduce nausea.

    Medical Disclaimer

    The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.

    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.