Outcome
    Preliminary

    Chlorella for Immune Function

    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.

    Overview

    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.

    Verdict

    Mixed evidence

    How It Works

    Chlorella cell-wall polysaccharides (beta-glucans and chlorellan) appear to prime innate immune cells, while its carotenoids and chlorophyll reduce oxidative stress that impairs immune function. Increased secretory IgA suggests enhanced mucosal immunity.

    Dosing & Protocol

    Typical dose

    Recommended dose
    5-6 g/day of tablets or powder, in divided doses with meals
    Expected timeframe
    4-12 weeks

    Protocol

    form
    Broken cell wall chlorella from a brand that tests for heavy metals and microcystins
    timing
    With meals
    duration
    8-12 weeks
    titration
    Increase by 1 g every few days to 5-6 g/day in divided doses
    honest note
    A handful of trials show increased salivary IgA in athletes and improved NK activity in healthy adults, and one Japanese trial showed reduced cold symptoms - these are small studies with surrogate endpoints
    measurement
    Count upper respiratory infection days across a season; salivary IgA and NK activity are laboratory measures you cannot track at home
    starting dose
    1-2 g/day with food for the first week - starting at full dose commonly causes gas, cramping and green stools

    Evidence

    What the studies say

    A handful of RCTs show increased sIgA in athletes and improved NK activity in healthy adults, and one Japanese trial showed reduced dioxin in breast milk. However, sample sizes are small, blinding is difficult (green powder), and there is no large trial on infection incidence. Treat as a reasonable food-based adjunct, not an immune shield.

    No studies are yet linked to both Chlorella and Immune Function.

    Safety

    Caveats

    Product quality is the main risk: algae concentrate heavy metals and can be contaminated with microcystins, so buy only third-party tested chlorella. Common side effects are gas, bloating, cramping, green stools and photosensitivity. It is high in vitamin K, which interferes with warfarin dosing. Caution in autoimmune disease, since the mechanism is immune stimulation, and avoid with immunosuppressants or after transplant. Avoid with iodine sensitivity or a mould or algae allergy. Not established in pregnancy or breastfeeding. Immune surrogate markers are not health outcomes.

    Less likely to help if

    Healthy low-stress adults with limited exposure, and anyone who cannot tolerate the gastrointestinal effects.

    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.