| Creatine Monohydrate Creatine (creatine monohydrate) is a
colorless, crystalline substance used in muscle tissue for the production of
phosphocreatine, an important factor in the formation of adenosine triphosphate (ATP), the
source of energy for muscle contraction and many other functions in the body.
Creatine monohydrate supplementation
increases phosphocreatine levels in muscle in most people, especially when accompanied by
exercise or carbohydrate intake. However, about 30% of people who take creatine
supplements fail to retain significant quantities in the muscle, which may explain the
inconsistent results reported in studies of the effects of creatine on athletic
performance.
Creatine may increase exercise-related
gains in lean body mass, though how much of these gains represents more muscle and how
much is simply water retention is unclear. Most, though not all, controlled studies have
shown that 20 grams per day of creatine monohydrate taken for five to six days by
sedentary or moderately active people, improves performance and delays muscle fatigue
during short-duration, high-intensity exercise such as sprinting or weight lifting.
However, elderly people appear to gain only minimal, if any, exercise performance benefits
from creatine supplementation, and performance outcomes for trained athletes using
creatine supplements in competitive situations have not been consistent. Creatine
supplementation does not appear to increase endurance performance and may impair it by
contributing to weight gain.
Very little research has been done to
investigate the exercise performance effects of long-term (over one month) creatine
supplementation. Two controlled long-term trials using untrained women or trained men
found that creatine improved gains made in strength and lean body mass from
weight-training programs. However, a third preliminary trial found only insignificant
gains from creatine supplementation in weight-training football players.
The amount of creatine within cells may be
deficient in people with muscular dystrophy. This deficiency may contribute to the
weakness and degeneration of muscle tissue seen in this condition. A case report described
a 9-year old boy with muscular dystrophy who experienced improved muscle performance after
creatine supplementation. A double-blind trial found that creatine supplementation (10
grams per day for adults, 5 grams per day for children) slightly but significantly
improved muscle strength and performance of daily activities in people with varying types
of muscular dystrophy. Creatine supplementation has also been reported to improve strength
in certain rare diseases of muscle and energy metabolism. |