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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.

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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.

How to take it

TimingTiming does not matter; trials simply dosed it daily.
With food?Take it with a meal containing some fat, since it is a lipid-soluble rice bran component.
Worth knowingCheck the label for milligrams of gamma-oryzanol itself, because many products declare rice bran oil weight instead.

Frequently asked questions

Does gamma-oryzanol lower cholesterol?

Gamma-oryzanol has limited evidence for cholesterol: in a trial in 30 men, rice bran oil with 0.05 g/day or 0.8 g/day of gamma-oryzanol lowered LDL by about 10% equally. That suggests the benefit came from the rice bran oil's sterols, not the gamma-oryzanol.

Does gamma-oryzanol build muscle or raise testosterone?

No, two randomised trials in resistance-trained men using 500–600 mg/day of gamma-oryzanol found no meaningful advantage over placebo for strength or body measurements. The testosterone-boosting claim has not held up in humans, so the evidence is limited.

Does gamma-oryzanol help menopausal hot flashes?

The hot-flush claim for gamma-oryzanol traces back to uncontrolled Japanese case series from the 1960s and 1980s. No modern placebo-controlled trial has tested gamma-oryzanol for hot flushes, so the evidence is limited.

How much gamma-oryzanol should I take?

Trials of isolated gamma-oryzanol used 300–600 mg/day, and labels typically give 300 mg per serving, taken with a meal containing some fat. Check that the label lists milligrams of gamma-oryzanol itself, not rice bran oil weight.

Scientific references

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