Gamma Oryzanol

What other names is Gamma Oryzanol known by?

Gama Orizanol, Gamma-Oryzanol, Gamma-OZ, Oryzanol.

What is Gamma Oryzanol?

Gamma oryzanol is a substance that is taken out of rice bran oil. It is also found in wheat bran and some fruits and vegetables. People use it as medicine.

Gamma oryzanol is used for high cholesterol and symptoms of menopause and aging.

Some people use it for increasing testosterone and human growth hormone levels, as well as improving strength during resistance exercise training.

Possibly Effective for...

  • High cholesterol levels. Most research shows that taking gamma oryzanol by mouth decreases total cholesterol, "bad" low-density lipoprotein (LDL) cholesterol, and blood fats called triglycerides in people with high cholesterol. However, the effects of gamma oryzanol on "good" high-density lipoprotein (HDL) cholesterol are mixed. Taking gamma oryzanol along with vitamin E, omega-3 fatty acids, and niacin by mouth for 4 months also seems to reduce LDL cholesterol in people with high cholesterol. However, one study suggests that consuming rice bran oil containing a high amount of gamma oryzanol for 4 weeks does not reduce LDL cholesterol better than rice bran oil containing a low amount of gamma oryzanol in men with high cholesterol.

Insufficient Evidence to Rate Effectiveness for...

  • Athletic performance. Early research suggests that taking gamma oryzanol by mouth for 9 weeks while participating in resistance training does not improve muscular strength or jump power in well-trained male athletes.
  • Itchy and inflamed skin (eczema). Early research suggests that bathing in bathwater containing gamma oryzanol each day for up to 6 months improves symptoms of eczema in children.
  • Menopause symptoms.
  • Other conditions.
More evidence is needed to rate the effectiveness of gamma oryzanol for these uses.

How does Gamma Oryzanol work?

Gamma oryzanol might reduce cholesterol levels by reducing absorption of cholesterol from foods.

Gamma oryzanol is also often promoted for treating menopause, but it is unclear how it would work for this use. Some researchers suspect it might be helpful due to effects on luteinizing hormone (LH). However, this effect has not been shown in people.

Some people use gamma oryzanol for increasing testosterone and growth hormone levels. However, gamma oryzanol appears to have no effect on these hormone levels. In fact, animal studies suggest that gamma oryzanol might even reduce testosterone production.

Are there safety concerns?

Gamma oryzanol is POSSIBLY SAFE for most adults when taken by mouth or applied to the skin. However, the potential side effects of gamma oryzanol are not known.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking gamma oryzanol if you are pregnant or breast-feeding. Stay on the safe side and avoid use.

Under-active thyroid (hypothyroidism): Gamma oryzanol might lower thyroid function. Don't use gamma oryzanol if you have thyroid problems.

Dosing considerations for Gamma Oryzanol.

The following doses have been studied in scientific research:

  • For lowering cholesterol: the usual dose of gamma oryzanol is 300 mg daily. In one study, 100 mg three times daily was used.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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Last Editorial Review: 3/29/2011