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15 Science-backed Health Benefits of Gamma Oryzanol

Written by Biljana Novkovic, PhD | Last updated:
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology) | Written by Biljana Novkovic, PhD | Last updated:

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Gamma oryzanol is a compound found in rice bran oil. It lowers cholesterol and decreases inflammation. Due to its antioxidant activity, it combats wrinkles and skin aging. In addition, this supplement may also help with diabetes, insulin sensitivity, obesity, and allergies. Although gamma oryzanol has been used in Japan for decades, studies are still uncovering its many potential health benefits. Read on to find out why this supplement is gaining in popularity.

What Is Gamma Oryzanol?

Gamma oryzanol occurs in rice bran oil at a level of 1 to 2%. It comprises a mixture of ferulic acid esters and phytosterols [1, 2].

Apart from rice, it is also found in wheat, maize, rye, triticale, and barley, but at much lower levels [3].

It has been used as a supplement in Japan since the early 70s.

Gamma oryzanol:

  • lowers bad cholesterol. Phytosterols (plant sterols) found in this supplement have a structure similar to cholesterol and are well known for their LDL-cholesterol-lowering effect [4].
  • is anti-inflammatory [5, 6].
  • lowers blood glucose [7].
  • is an antioxidant. This is due to ferulic acid, a strong antioxidant that protects cells from reactive oxygen species (ROS) [8, 9].

Gamma oryzanol is commonly used as an exercise supplement as well as to build muscles. However, the results regarding muscle strength are controversial.

It is much more promising as a supplement that decreases cholesterol and helps with inflammation.

Mechanisms of Action

Gamma oryzanol decreases cholesterol by:

  • Decreasing the uptake of cholesterol by gut cells [10].
  • Decreasing HMG-CoA reductase activity. HMG-CoA reductase is an enzyme that promotes cholesterol production [10, 11].
  • Blocking the formation of micelles, which are small aggregates of molecules that often contain cholesterol [10, 12].

This supplement lowers inflammation by:

  • Decreasing NF-kB – the master-regulator of inflammation [13].
  • Decreasing inflammatory molecules PGE2, COX-2, TNF-alpha, and IL-6 [5, 6].
  • Lowering CRP – a marker of chronic low-grade inflammation [14].

Gamma oryzanol is an antioxidant. It removes organic radicals [15].

It lowers blood glucose levels by increasing PPAR-γ and C/EBPα, which increase the uptake of glucose by cells [7].

This compound combats cancer by:

  • Increasing the activity of natural killer cells, which combats tumor cell growth [16, 17].
  • Reducing caveolin-1 and PCGEM1 expression. These genes are involved in the development and progression of prostate cancer [18].
  • Suppressing blood vessel formation to inhibit tumor growth [17].

Health Benefits of Gamma Oryzanol

1) Decreases Cholesterol

Gamma oryzanol blocks the uptake of cholesterol by gut cells, as it decreases HMG-CoA reductase, an enzyme that promotes cholesterol production. This supplement also increases cholesterol removal by bile acids [10, 19].

In 30 men with high cholesterol, rice bran oil, with varying amounts of gamma oryzanol, was able to lower total and LDL cholesterol levels. However, there was little difference between the cholesterol-lowering effects of the high and low gamma oryzanol-containing rice bran oil [20].

Gamma oryzanol decreased total cholesterol and LDL cholesterol levels in 20 schizophrenia patients with high cholesterol [21].

In another study, this supplement lowered cholesterol and improved fat metabolism in rats fed a high-cholesterol diet [22].

The compound was effective in lowering LDL-cholesterol levels and increasing HDL-cholesterol in rats. Low HDL and high LDL-cholesterol increase the risk of heart disease [23, 24].

Gamma oryzanol decreased cholesterol levels in hamsters with high cholesterol [25].

It also lowered cholesterol absorption by 20% and increased cholesterol removal by bile acids in rats [19].

2) May Prevent Hardening of the Arteries (Atherosclerosis)

Rice bran enzymatic extract (containing gamma oryzanol) lowered cholesterol and prevented atherosclerotic plaque development in atherosclerosis-prone mice on a high-fat diet [26, 27].

This compound decreased cholesterol and reduced “aortic fatty streaks” in hamsters. Fatty streaks are the first visible damage in the hardening of the arteries [28].

However, it was ineffective in treating hardening of the arteries (atherosclerosis) in rabbits [29].

3) May Improve Muscle Strength

A study of 30 healthy participants found that gamma oryzanol improved bench press and leg curl results, showing that the supplement may have improved muscle strength during resistance training [30].

However, another study on 22 weight-trained men showed that nine weeks of gamma oryzanol supplementation did not influence performance [31].

4) May Be Beneficial in Diabetes

Gamma oryzanol improved glucose levels in mice by improving the function and survival of pancreatic beta cells (cells that release insulin) [32].

This compound directly acts on pancreatic cells to enhance glucose-stimulated insulin release [33].

Also, it directly enhances glucose uptake by fat cells (adipocytes) [7].

This supplement effectively prevented the decrease of adiponectin levels in mice. Low adiponectin is a risk factor for diabetes [34].

5)May Improve Insulin Sensitivity

Gamma oryzanol increased insulin sensitivity in rats with type 2 diabetes [35].

When pregnant mice are fed a high-fat diet, their offspring develop insulin resistance. Gamma oryzanol given to pregnant mice prevented the development of insulin resistance in the offspring [36].

6) May Combat Obesity

A study performed on rats suggests that gamma oryzanol can combat obesity by blocking dopamine receptors (D2R) in the brain (striatum). These receptors are part of the brain reward system. They are increased by a high-fat diet, resulting in hedonic overeating [37].

This compound reduced the preference for dietary fats, and reduced obesity and fat accumulation in rats fed a high-fat and high-fructose diet [38, 14].

It also decreased the production of fat cells (adipocytes) [39].

7) Gamma Oryzanol and Cancer

Gamma oryzanol inhibited colon tumor growth in mice by [17]:

Cycloartenol ferulate, a component of gamma oryzanol, reduced the growth of skin tumors in mice [40].

Gamma oryzanol inhibited the growth of human prostate cancer cells [41, 18].

However,  a study on rats reported a rare side effect of gamma oryzanol – promoting lung cancer. But its effect is weak and occurs only at a very high dosage [42].

8) Improves Your Skin

When delivered under the skin via an injection, gamma oryzanol protected against skin-aging and improved wrinkles in 15 people and UV radiation-exposed rats [43].

Also, when it was incorporated into a cream and applied to the skin, it hydrated and lightened the skin [44].

9) May Combat Osteoporosis

This compound increased bone density and calcium content in a rat model of osteoporosis (female rats that had their ovaries removed) [45].

Another study found that it increased bone formation-related genes in rats (SP7/OSX, POSTN, RUNX2, and COL1 and 2) [46].

10) Is Anti-Inflammatory

In rats, gamma oryzanol decreased inflammatory mediators such as PGE2, TNF-alpha, and IL-6 [5].

This supplement reduced lung inflammation in rats with sepsis [47].

It also decreased IL-6 and a marker of chronic low-grade inflammation, CRP, in rats with metabolic syndrome [14].

Gamma oryzanol also decreases other inflammatory parameters, such as COX-2 and Nf-kB [13, 6].

11) May Prevent Anaphylaxis

Anaphylaxis is an extreme allergic reaction characterized by swelling and difficulty breathing.

A component of gamma oryzanol called cycloartenol ferulate was able to reduce mast cell degranulation (mast cells release histamine and other inflammatory agents), which decreased the anaphylaxis reaction in rats [48].

12) May Promote Hair Growth

A rice bran extract containing gamma oryzanol promoted hair growth and the formation of new hair follicles in mice [49].

13) May Improve the Immune Response

This supplement increased cytokines IL-8 and CCL2 and enhanced the activity of macrophages ( a type of white blood cells) important for the innate immune responses [50].

14)  May Protect from Heavy Metal Toxicity

This compound protected mice against cadmium-induced testicular toxicity and oxidative stress [51].

15) May Prevent Ulcers

In a couple of studies, gamma oryzanol prevented stress-induced ulcers in rats [52, 53].

Limitations and Caveats

Since most of the studies mentioned here were on animals, caution should be taken when using gamma oryzanol for its health benefits in humans.

Despite the frequent use of gamma oryzanol by athletes as a strength supplement, there is limited evidence available to support the effects of this compound on muscle strength during resistance training [30].

The testosterone-lowering effects of gamma oryzanol are only theoretical and haven’t yet been proven [54].

Further studies are needed to confirm that gamma oryzanol reduces HMG-CoA reductase activity in humans [10].

Gamma Oryzanol and Hormones

Gamma oryzanol did not influence testosterone, cortisol, estradiol, growth hormone, or insulin levels in humans [31].

Another study found that an injection of gamma oryzanol into rats suppressed growth hormone and prolactin release [55].

This compound was a potent inhibitor of luteinizing hormone release and a weak inhibitor of prolactin in rats [56].

It lowered thyroid-stimulating hormone (TSH) levels in 6 of the 8 studied hypothyroid patients the blood [57].


Gamma oryzanol and its source rice bran oil are generally considered to be safe, with little to no side effects reported in studies.

Gamma oryzanol is a promoter of lung cancer in rats, but its effect is weak and occurs only at a very high dosage [42].

It was found to be not carcinogenic (cancer-causing) in studies on B6C3F1 mice and F344 rats [58, 59].



Gamma oryzanol is generally administered orally at a variety of doses.

Some studies used a lower dose of around 50 to 60 mg daily [60, 61].

One study (referenced in a review) administered gamma oryzanol thrice daily at 20 mg [60].

Others used a higher dose, between 300 and 800 mg daily [62, 30].

User Experiences

  • “This got rid of my ulcer. It took a while, but it works.”
  • “I would not recommend this as a workout-related antioxidant. Gamma Oryzanol is not very effective.”
  • “I was surprised to feel a difference. My muscles are less sore, I lost weight and my sexual performance improved. No apparent side effects. This is one of the few products I’ve used that is effective even after a few weeks of use.”
  • “As an integrative medicine doctor, I have used this a lot in my patients and they’ve had great results. It has almost no side effects and it is cheap.”

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About the Author

Biljana Novkovic

Biljana received her PhD from Hokkaido University.
Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science & health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

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