Methoxyisoflavone
syn. 5-methyl-7-methoxyisoflavone
PERFORMANCE VALIDATION SCORES
Combined 2
Clinical Support Rating 0
Empirical Evidence Rating 2
Description
Methoxyisoflavone (5-methyl-7 methoxyisoflavone) is a flavonoid from soy. Flavonoids are a broad class of natural polyphenolic compounds widely found in
fruits and vegetables. These compounds generally have antioxidant activities, and may be responsible for some of the health-promoting aspects of fruits and vegetables. Depending on individual structure, many flavonoid compounds also possess additional biological activity. Flavonoids are extremely common and
diverse in structure, however, which makes determining the potential unique biological activity of each very difficult.
Methoxyisoflavone belongs to a specific flavonoid category called isoflavonoids. These compounds all share a common 3-phenylchromen-4-one backbone,
and are found exclusively in the legume (bean) family. There have, unfortunately, been few specific studies on this particular isoflavonoid. Methoxyisoflavone has been widely promoted by sports nutrition manufacturers to improve exercise performance in humans, especially for increasing muscle mass and strength.
Presently, however, it is unclear if
any performance-enhancing activity is actually present in this substance.
Promoted Benefits
Methoxyisoflavone is promoted to help increase muscle mass, strength, and athletic performance.
Clinical Studies
The use of methoxyisoflavone as a sport supplement is not supported by peer-reviewed clinical studies. Its Clinical Support Rating is 0 (0/5). Sport supplement manufacturers commonly cite two pieces of research to support the sale of methoxyisoflavone. The first is the original 1970’s patents for this supplement.52,46 This data cannot be considered reliable, however, as it does not come from a peer-re-
viewed scientific study, and may be the subject of bias. It is also well understood that the U.S. Patent Office is focused much more on the novelty and unobvious nature of an invention that validating the scientific methods contained in it.
The second is a placebo-controlled study published in 2001 that demonstrated a 13 kg lean body mass gain in resistance-trained men who took 800 mg/day of methoxyisoflavone for eight weeks. This paper cannot be accepted as clinical validation, however, as it was only published as an abstract (there is no re-
view of the methods), did not disclose the probability value for lean body mass gain (no way to determine what the authors considered statistically significant), and was authored in part by a representative of the supplement’s manufacturer.
This leaves only one peer-reviewed published
placebo-controlled study that examines the effects of methoxyisoflavone supplementation on exercising adults. The study also involved supplementation for eight weeks (800 mg/day) in a group of men with resistance-training experience. A detailed resistance-
training program was followed as part of the study, and measurements of strength and anaerobic performance were taken at various points. Investigators could not find any statistically significant or strong trends of
improvement caused by methoxyisoflavone in any marker of performance, anabolic/catabolic status, or body composition. This study does not support the use of methoxyisoflavone as a sport supplement.
Empirical Evidence
Methoxyisoflavone has been widely used as a stand alone product. The empirical evidence on this supplement has been weak. Most users fail to notice any significant body composition or performance benefits from its use. A smaller percentage of users, however, do claim to see results from taking it. When reported, positive results are usually centered on muscle and strength gains, not necessarily anaerobic or
aerobic performance. Methoxyisoflavone products remain in active commerce today. Whether this is the result of marketing hype, or tangible improvements and repeat consumer business, remains unclear.