BodybuildingGod.com

Nitric oxide-boosting supplements burst onto the bodybuilding scene a few years ago, and scientists since then have consistently looked for new compounds to further enhance nitric oxide production. Arginine has been the clear favorite for use in supplements, but several other ingredients can work synergistically with arginine to further nitric oxide levels.

The latest player is a novel ingredient known as GPLC, a patented compound that combines the amino acid glycine with propionl-L-carnitine. Scientists came up with the idea of combining these two ingredients after studies in animals and humans showed that each compound alone could stimulate nitric oxide production; however, those early investigations involved injections into the bloodstream. The first study to measure the effects of GPLC in supplement form was performed on a group of inactive men. This research demonstrated the ability of GPLC to increase nitric oxide production, which led the same group of researchers to test its effects during exercise.

Researchers from the University of Memphis (Tennessee) designed an experiment in which trained male weightlifters supplemented with 4.5 grams of GPLC daily or a placebo for four weeks. Each subject then took a two-week break to clear his body of the compound. Then, the subjects received the alternate treatment (GPLC or placebo) for an additional four weeks. At the end of each four-week supplementation period, a test was performed in which subjects did handgrip exercises for six minutes and then had nitric oxide levels measured.

Subjects receiving GPLC experienced an increase in nitric oxide levels that was 30% higher than the ones receiving placebo. The researchers believe GPLC may work by increasing the activity of nitric oxide synthase, which is the enzyme responsible for catalyzing the conversion of arginine into nitric oxide. GPLC may also decrease production of certain free radicals, which are known to increase the break down of nitric oxide.

As far as dosage goes, taking 4.5 grams of GPLC per day can increase and boost nitric oxide levels and blood flow for improved muscle pumps during exercise. More nitric oxide also means a greater delivery of amino acids, carbohydrates, anabolic hormones and oxygen to muscle during exercise recovery, which can stimulate increased recovery and muscle growth. Subjects in the study took GPLC twice a day with carbohydrate containing meals (carb intake help increase GPLC uptake). Therefore, your best bet is to take 2-3 grams of GPLC with your pre-workout and post-workout meals, or with breakfast and dinner on rest days.