Limited evidenceImmunity

Rice Bran Arabinoxylan

An enzymatically modified rice bran fibre (sold as MGN-3 or BioBran) that reliably raises natural killer cell activity in small trials. Whether that translates into fewer infections or better outcomes has never been shown.

Evidence last reviewed: August 2026

What the science says

Higher natural killer cell activity Limited evidence
A randomized, double-blind, placebo-controlled trial in geriatric subjects reported increased NK cell activity after supplementation, and a randomized study in multiple myeloma patients found changes in innate immune cell populations. Both trials were small and measured immune markers rather than health outcomes.
No demonstrated clinical benefit Limited evidence
An evidence-based review of BioBran/MGN-3 as a complementary cancer therapy concluded that the studies are small, frequently uncontrolled and heterogeneous, and that effects on survival or infection rates are not established.

Dosage & safety

Studied doseTrials have used roughly 500 mg to 3 g per day, often with a higher loading dose for the first weeks. Labels commonly suggest 1 g per day.

SafetyWell tolerated in the published trials, with mild gastrointestinal effects the main complaint. Because it is presented as an immune activator, caution is reasonable in autoimmune disease and alongside immunosuppressant therapy. No data in pregnancy. Much of the research comes from investigators connected to the manufacturer.

Scientific references

Biobran/MGN-3, an arabinoxylan rice bran, enhances NK cell activity in geriatric subjects: A randomized, double-blind, placebo-controlled clinical trial
Elsaid AF, Shaheen M, Ghoneum M — Exp Ther Med, 2018
MGN-3 arabinoxylan rice bran modulates innate immunity in multiple myeloma patients
Cholujova D, Jakubikova J, Czako B, Martisova M, Hunakova L, Duraj J, Mistrik M, Sedlak J — Cancer Immunol Immunother, 2013
Evidence-Based Review of BioBran/MGN-3 Arabinoxylan Compound as a Complementary Therapy for Conventional Cancer Treatment
Ooi SL, McMullen D, Golombick T, Nut D, Pak SC — Integr Cancer Ther, 2018

Where to buy

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