Supplement analysis backed by scientific evidence · PT

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Limited evidenceHeart & metabolic

Gamma-Oryzanol

A mixture of ferulated plant sterols from rice bran oil. The best-designed test found the cholesterol lowering comes from the oil, not the oryzanol, and the bodybuilding claims failed in controlled trials.

Evidence last reviewed: August 2026

What the science says

  • Cholesterol lowering Limited evidence

    A randomised parallel trial in 30 mildly hypercholesterolaemic men compared rice bran oil containing 0.05 g/day versus 0.8 g/day of gamma-oryzanol. Both lowered LDL by about 10%, and the two oils did not differ, which argues the benefit came from the oil's sterols rather than the oryzanol.

  • Strength and anabolic effects Limited evidence

    Two randomised trials in resistance-trained men, one using 600 mg/day for 9 weeks and one 500 mg/day, found no meaningful advantage over placebo for strength or anthropometric measures. The claimed testosterone-boosting mechanism has not held up in humans.

  • Menopausal hot flushes Limited evidence

    The hot-flush claim traces to uncontrolled Japanese case series from the 1960s and 1980s; no modern placebo-controlled trial has tested gamma-oryzanol for vasomotor symptoms.

Dosage & safety

Studied doseTrials of the isolated compound used 300–600 mg/day. Typical supplement labels give 300 mg per serving.
SafetyWell tolerated; occasional dry mouth, drowsiness and mild gastrointestinal upset have been reported. It may affect thyroid hormone and prolactin secretion in principle, though this has not been shown to matter clinically. Not for anyone with a rice allergy, and there is no data in pregnancy.

Scientific references

Where to buy

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