What is it?
Gamma oryzanol is a naturally occurring mixture of plant chemicals called sterols and ferulic acid esters.
Where is it found?
Gamma oryzanol is a natural component of rice bran, corn, and barley oils. Gamma oryzanol is also available as a supplement.
Why do athletes use it?*
Some athletes say that gamma oryzanol
- helps increase muscle size and strength gains.
- helps reduce fatigue.
What do the advocates say?*
Gamma oryzanol and its related compound ferulic acid are thought to affect hormone function in the body, resulting in anabolic effects on muscle growth as well as reduced sense of fatigue. Early studies appeared promising, but a recent double-blind trial cast doubt on any real benefits.
It appears that gamma oryzanol is very poorly absorbed from the gastrointestinal tract.
How much is usually taken by athletes?
Gamma oryzanol is a mixture of sterols and ferulic acid esters. Despite claims that gamma oryzanol or its components increase testosterone levels, stimulate the release of endorphins, and promote the growth of lean muscle tissue, research has provided little support for these claims and has also shown gamma oryzanol to be poorly absorbed.1 A nine-week, double-blind trial of 500 mg per day of gamma oryzanol in weight lifters found no benefit compared with placebo in strength performance gains or circulating anabolic hormones.2 However, a small, double-blind trial using 30 mg per day of ferulic acid for eight weeks in trained weight lifters did find significantly more weight gain (though lean body mass was not measured) and increased strength in one of three measures compared with placebo.3
Are there any side effects or interactions?
Some research suggests that gamma oryzanol taken in moderately high amounts (up to 600 mg per day) for several months can cause dry mouth, sleepiness, hot flushes, irritability, and light headedness in some individuals.4
*Athletes and fitness advocates may claim benefits for gamma oryzanol based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles on gamma oryzanol. For more complete and detailed information, including references and safety information, see Gamma Oryzanol as a nutritional supplement.
References
1. Wheeler KB, Garleb KA. Gamma oryzanol-plant sterol supplementation: metabolic, endocrine, and physiologic effects. Int J Sport Nutr 1991;1:170–7 [review].
2. Fry AC, Bonner E, Lewis DL, et al. The effects of gamma-oryzanol supplementation during resistance exercise training. Int J Sport Nutr 1997;7:318–29.
3. Bucci LR, Blackman G, Defoyd W, et al. Effect of ferulate on strength and body composition of weightlifters. J Appl Sport Sci Res 1990;4:110 [abstract].
4. 34. Takemoto T, Miyoshi H, Nagashima H. Clinical trial of Hi-Z fine granules (gamma-oryzanol) on gastrointestinal symptoms at 375 hospitals (Japan). Shinyaku To Rinsho 1977;26 [in Japanese].
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2006-09-07
