Glycocarn
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GlycoCarn is glycine propionyl L-carnitine Hydrochloride or GPLC, a propionyl ester of carnitine that includes an additional glycine component. It has been the focus of several research studies involving human subjects over the past few years, with findings such as increased resting [1] and stress-induced plasma nitrate/nitrite—a surrogate marker of nitric oxide production,[2] improved antioxidant defense , improved high intensity exercise performance [2], and a reduction in blood lactic acid in response to repeated high intensity cycle sprints.[3]
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[edit] Nitric oxide stimulant
GlycoCarn has been shown in two recent studies to result in an increase in blood levels of nitrate/nitrite [3] (a surrogate marker of Nitric Oxide [4]; not a direct measure of Nitric Oxide), when used at a daily dose of 4.5 grams. In one study, GlycoCarn [5] was provided to previously sedentary men and women who were also assigned to supervised aerobic exercise for eight weeks.[1] A significant increase in resting levels of blood nitrate/nitrite was noted for subjects receiving GlycoCarn compared to placebo (in a double blind design). Subjects who received GlycoCarn were also noted as having lower levels of malondialdehyde, a lipid peroxidation biomarker indicating free radical mediated oxidation of lipids. Increased free radical production may be associated with impaired Nitric Oxide bioavailability [6].
In another study, GlycoCarn or a placebo was provided to resistance trained men for four weeks each, with a two week washout period between each four week period, using a double blind design.[2] At the end of each four week period, resting blood samples were obtained, in addition to blood samples following Isometric exercise. It is possible that this increase in nitrate/nitrite may have implications related to enhanced blood flow during acute bouts of exercise [7].
[edit] Antioxidant
In addition to regular exercise, nutritional antioxidants may combat free radical formation—as has been reported for GlycoCarn.[1] In this study, subjects received oral GlycoCarn at a dosage of either 1.5 or 4.5 grams per day over the course of an eight week intervention period. With both dosages, the post-intervention level of malondialdehyde, a marker of lipid peroxidation, was decreased as compared to pre-intervention values. The same was not true for subjects receiving a placebo. These findings highlight the significant antioxidant properties of GlycoCarn. More recent work using GlycoCarn to combat resistance exercise-induced lipid peroxidation has also noted favorable findings (unpublished data). While many athletes now use GlycoCarn as a component of their dietary supplement regimen, future work is needed to investigate the impact of GlycoCarn on decreasing oxidative stress resulting from strenuous exercise [8].
In support of the above, previous work involving the individual components of GlycoCarn has noted decreased protein and lipid peroxidation following glycine use,[4] with potent antioxidant properties noted for propionyl-L-carnitine.[5]
[edit] Ergogenic aid
Although still relatively new in the field of sport nutrition, GlycoCarn has been used by some athletes reporting favorable results in terms of exercise performance and recovery [9]. Preliminary work with previously sedentary subjects failed to indicate performance effects related to VO2max assessed via graded exercise treadmill testing or anaerobic power assessed via a 30-second cycle sprint.[6] However, a recent study involving active men noted very favorable performance effects of GlycoCarn, as well as a significant reduction in blood lactic acid, a byproduct of anaerobic metabolism thought to impair muscle performance.[7]
Specifically, in this study conducted by Dr. Patrick Jacobs and colleagues, 24 healthy, exercise trained men consumed either 4.5 grams of GlycoCarn or a placebo on two different days separated by one week (double blind, cross-over study design). Ninety minutes following ingestion of the assigned treatment, subjects performed five, maximal effort cycle sprints, each lasting 10 seconds in duration. They were given one minute of “active” recovery between each sprint. The peak and mean power output, as well as the blood lactic acid, was measured for both conditions. Results indicated that power output was up to 15% higher following the GlycoCarn trials compared to placebo, while post-exercise blood lactic acid was 15-16% lower compared to placebo. These data are in reference to trained men performing repeated cycle sprints. Therefore, it is difficult to extrapolate these findings to other activities.
[edit] Scientific summary
GlycoCarn has been shown to increase resting and stress-induced plasma nitrate/nitrite, improve antioxidant defense,[1] improve high intensity exercise performance, and result in a reduction in blood lactic acid in response to repeated high intensity cycle sprints [8]
[edit] Practical applications
In terms of dosing and timing of intake, the scientific work with GlycoCarn has involved a single dosage of 4.5 grams taken without food 90 minutes prior to exercise or a daily dosage of either 1.5 or 4.5 grams taken in two divided dosages along with a carbohydrate-rich meal, which may aid in carnitine retention in muscle.[9] With the exception of the antioxidant benefits, an increased plasma nitrate/nitrite have been observed using 4.5 grams daily for 4–8 weeks, while those in relation to improved exercise performance and reduced blood lactic acid have been observed using a single serving of 4.5 grams.[3]
[edit] References
- ^ a b c d (Bloomer RJ, Tschume LC, Smith WA: Glycine propionyl-L-carnitine modulates lipid peroxidation and nitric oxide in human subjects. Int J Vitam Nutr Res; 79(3): 131-141, 2009)
- ^ a b (Bloomer RJ, Smith WA, Fisher-Wellman KH. Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance trained men. J Int Soc Sports Nutr; 4(1): 22, 2007)
- ^ a b (Jacobs PL, Goldstein ER, Blackburn W, Orem I, Hughes JJ. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr. 6(9): Epub Apr 2, 2009.)
- ^ (Malyshev VV, Oshchepkova OM, Seminokii IZH, Nefedova TV, Morozona TP. The limitation of lipid hyeroxidation nad the prevention of stressor damages to the heart by glycine derivatives. J Exp Clin Pharmocol; 59: 23-25, 1996.)
- ^ (Reznick AZ, Kagan VE, Ramsey R. Antiradical effects in L-propionyl carnitine [1] protection of the heart against ischemia-reperfusion injury: the possible role of iron chelation. Arch Biochem Biophys: 296: 394-401, 1992.)
- ^ (Smith WA, Fry AC, Tschume LC, Bloomer RJ. Effect of glycine propionyl-L-carnitine on aerobic and anaerobic exercise performance. Int J Sport. Nutr Exerc Metab; 18(1): 19-36, 2008.)
- ^ (Jacobs PL, Goldstein ER, Blackburn W, Orem I, Hughes JJ. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr. 6(9): Epub Apr 2, 2009.)
- ^ (Jacobs PL, Goldstein ER, Blackburn W, Orem I, Hughes JJ. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males. J Int Soc Sports Nutr. 6(9): Epub Apr 2, 2009.)
- ^ (Stephens FB, Evans CE, Constantin-Teodosiu D, Greenhaff PL: Carbohydrate ingestion augments L-carnitine retention in humans. J Appl Physiol: 102(3): 1065–1070, 2007.)
