Due to the high emotional stakes involved in both amateur and professional sports, pharmaceutical and supplement manufacturers continually seek to find products that might add a competitive edge. Findings from test tube studies suggested that an extract of the brown seaweed Cystoseira canariensis might inhibit a substance in the body called myostatin.1 Myostatin inhibits the growth of muscle cells. It is believed that some animals, and some people, produce relatively less myostatin, and therefore develop stronger muscles even without much exercise. Consider chimpanzees that live in a cage but are nonetheless much stronger than similarly sized humans. If a substance could be discovered that effectively blocks the action of myostatin, that substance might logically be hypothesized to aid muscle growth.
Therefore, based on findings that can only be characterized as far too preliminary to rely upon at all, cystoseira became a widely marketed sports supplement.
Despite the test tube findings mentioned above, it is a very long way from test tube evidence to real life benefits. The vast majority of effects seen in the test tube do not ultimately translate into an effective treatment. In order to truly determine whether a treatment works, it must undergo human trials, and specifically one type of trial: the double-blind, placebo-controlled study. (The reasons why such studies are essential are presented in Why Does This Database Rely on Double-Blind Studies?) Only one such study has been performed on cystoseira, and it failed to find benefits.
In this 12 week, double-blind study, 22 males were randomly assigned to receive either placebo or 1200mg/day of cystoseira.2 Both groups underwent intensive resistance training (weight-lifting) for the duration of the trial. The results showed no difference in outcome between the treatment and the placebo groups.
While a single study cannot prove lack of efficacy, this outcome does clearly demonstrate that cystoseira has been brought to market prematurely.
A typical dose of cystoseira is 1200 mg per day, often divided into three doses.
Cystoseira is thought to be a safe, food-like substance. No serious adverse effects were seen in the human study described above. However, comprehensive safety testing has not been performed. Maximum safe doses in pregnant or nursing women, young children, or people with liver or kidney disease have not been determined.
1. Ramazanov Z, Jimenez del Rio M, Ziegenfuss T. Sulfated polysaccharides of brown seaweed Cystoseira canariensis bind to serum myostatin protein. Acta Physiol Pharmacol Bulg. 2003;27:101-6.
2. Willoughby DS. Effects of an alleged myostatin-binding supplement and heavy resistance training on serum myostatin, muscle strength and mass, and body composition. Int J Sport Nutr Exerc Metab. 2004;14:461-72.
Last reviewed August 2013 by EBSCO CAM Review Board Last Updated: 8/22/2013