What is Citrulline?

Citrulline is a non-essential amino acid, meaning that the body can manufacture it from other nutrients. Within the body, citrulline is converted to the amino acid L-arginine . Some of the proposed uses of citrulline supplements are based on raising levels of arginine. Citrulline also plays a role in a physiological process called “the urea cycle,” in which toxic ammonia is converted to urea.

There is little scientific support for any use of citrulline supplements.

Citrulline is most commonly marketed today as a supplement for enhancing sports performance . Based on exceedingly speculative reasoning, it is often described as an aerobic complement to the supplement creatine . Supposedly, citrulline enhances aerobic exercise capacity (relatively low-intensity exercise), while creatine enhances anaerobic exercise capacity (high-intensity exercise). However, while there have been numerous double-blind studies on creatine, available evidence on citrulline as a sports supplement is so scant that no conclusions whatsoever can be based on it. ¹ The only meaningful study reported thus far found that citrulline reducedrather than enhanced exercise capacity. ² Current...

Safety Issues

As a naturally occurring amino acid, citrulline is believed to be safe. However, maximum safe doses in young children, pregnant or nursing women, or people with severe liver or kidney disease have not been established.