Just so you know, the three supps tested against GlycoCarn were SP250, NO Xplod, and Nano Vapor.
I've been telling the guys who ask me to save their money. Now the research confirms what I have been preaching for a couple of years. And they used men who were already trained to eliminate the "newbie" response - very cool.
Take home: Malondialdehyde is a marker for lipid peroxidation, a process by which polyunsaturated fats become oxidated, resulting in oxidative stress. The GlycoCarn(R) supplement reduced MDA by 13.7%, which is significant. The NOx supplements actually caused a slight increase in malondialdehyde.
Comparison of pre-workout nitric oxide stimulating dietary supplements on skeletal muscle oxygen saturation, blood nitrate/nitrite, lipid peroxidation, and upper body exercise performance in resistance trained men
Journal of the International Society of Sports Nutrition 2010, 7:16doi:10.1186/1550-2783-7-16
Published 6 May 2010
We compared Glycine Propionyl-L-Carnitine (GlycoCarn(R)) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO2), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men.
Methods: Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn(R), or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO2 was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set.
Results: A condition effect was noted for StO2 at the start of exercise (p=0.02), with GlycoCarn(R) higher than SUPP2. A condition effect was also noted for StO2 at the end of exercise (p=0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p>0.05); however, MDA decreased 13.7% with GlycoCarn(R) and increased in all other conditions. Only a time effect was noted for HLa (p<0.0001),>0.05); however, GlycoCarn(R) resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%).
Conclusion: None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn(R) in terms of higher StO2 at the start of exercise. GlycoCarn(R) resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn(R)) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.
The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.
On the other hand, the makers of GPLC-GlycoCarn funded the study. This is their description of the product:
GlycoCarn® (GPLC) is glycine propionyl-L-carnitine hcl, USP a propionyl ester of carnitine that includes an additional glycine component. Compared with other forms of carnitine, GlycoCarn® exhibits a special affinity for muscle tissues, such as the heart, is a powerful scavenger against superoxide radicals and it protects against lipid peroxidation.They provide a lot of apparent support for their product:
GlycoCarn®, (Sigma-tau HealthScience brand of glycine propionyl-L-carnitine hcl, USP (GPLC), is a next generation member of the L-Carnitine family, with a particular focus on skeletal muscle, cardiac tissue, and the vascular system. Carnitine in general is known to be involved in fatty acid metabolism, and GlycoCarn® is a patented compound that has been shown to result in an increase in blood levels of nitric oxide (NO), as well as delivering potent antioxidant properties. Ongoing research also indicates that this compound may be associated with improved high intensity exercise performance. The performance effects of GPLC may be a result of both the nitric oxide stimulating and antioxidant activity, ultimately leading to increased blood flow and enhanced ATP energy production.
The applications for GlycoCarn® continue to be revealed, as funded research with this compound is presently ongoing at universities within the United States.Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males
Recent research has indicated that short term administration of glycine propionyl-L-carnitine(GPLC) significantly elevates levels of nitric oxide metabolites at rest and in response to reactive hyperaemia. However, no scientific evidence exists that suggests such supplementation enhances exercise performance in healthy, trained individuals. The purpose of this study was to examine the effects of GPLC on the performance of repeated high intensity stationary cycle sprints with limited recovery periods in resistance trained male subjects... (read more)Glycine Propionyl-L-Carnitine Increases Plasma Nitrate/Nitrite in Resistance Trained Men
We have recently demonstrated that oral intake of glycine propionyl-L-carnitine (GPLC) increases plasma nitrate/nitrite (NOx), a surrogate measure of nitric oxide production. However, these findings were observed at rest, and in previously sedentary subjects... (read more)GPLC Performance-Recovery Study
Recent research has indicated that short term administration of glycine propionyl-Lcarnitine (GPLC) significantly elevates levels of nitric oxide metabolites at rest and in response to reactive hyperaemia. However, no scientific evidence exists that suggests such supplementation enhances exercise performance in healthy, trained individuals. The purpose of this study was to examine the effects of GPLC on the performance of repeated high intensity stationary cycle sprints with limited recovery periods in resistance trained male subjects... (read more)The Efficacy of Dietary Supplementation for Enhanced Nitric Oxide Synthesis: The Scientific Evidence
Approximately twenty years ago, it was discovered that a particular factor produced within endothelial tissue specifically relaxes the adjacent smooth muscle of blood vessels thereby allowing vasodilation and increased blood flow to various tissues including skeletal muscle. This factor was initially referred to as endothelium-derived relaxing factor but is now known as nitric oxide... (read more)
The smarter, and less profitable, approach would be to tell the truth about its lipid peroxidation protection. In fact, it this product does target muscle tissue directly, it might be a useful supplement for treating fat deposits in diabetics, which decreases insulin sensitivity significantly.
Oh yeah, vitamin C and vitamin E have the same benefits in terms of reducing oxidative stress, but they do not target muscle tissue so precisely.
Anyway, now you know.