Introducing Creatine’s Little Brother- Glycocyamine
Dwayne N. Jackson, PhD
You may or may not know, but creatine has a little brother—glycocyamine [aka, guanidinoacetic acid (GAA)], which seems to be a promising new performance-enhancing supplement.
In the body, GAA is produced by the kidneys and pancreas and is a natural precursor to creatine production in the liver. Excitement for GAA as a new fitness supplement comes from the fact that it is essential for energy production in skeletal muscle, it has high oral bioavailability, and it can significantly boost the body’s creatine production.
In 2013, a study published in International Journal of Medical Sciences confirmed the creatine-boosting effect of supplemental GAA, where the authors reported up to a 50% increase in fasting serum creatine after 6 weeks of supplementation. Although research on GAA supplementation in unhealthy populations dates back to the 1950’s, up to recently there have been no studies investigating its performance-enhancing effects in healthy humans.
A most recent randomized, double-blinded, and placebo-controlled study published in the Journal of Investigative Medicine provides some of the newest data supporting the use of GAA as an ergogenic aid. In this collaborative study, researchers from Serbia and USA hypothesized that supplemental GAA may enhance exercise performance in humans in a dose-dependent manner. They reported that 6 weeks of GAA supplementation (up to 4.8g/day), without a combined exercise program, improved muscular fitness by up to approximately 25%. Most notable were increases in handgrip strength and maximum number of repetitions performed during bench press (to failure). Interestingly, there were no differences in lower body strength with GAA supplementation versus placebo.
ACTION POINT: This latest study provides novel data illustrating that 6 weeks of GAA can improve upper body strength and endurance without training. It will be interesting to see how improvements in strength develop when GAA is taken in combination with a structured resistance-training program—stay tuned, as more research comes out.
Although the current study showed that 6 weeks of GAA was safe and did not adversely affect liver health—before jumping on the bandwagon you must consider that there are health warnings about long-term GAA supplementation on its own. GAA causes increases in the body’s homocysteine levels, which (in the long-term) can promote cardiovascular disease. One way to safely avoid elevations in homocysteine is to take betaine (aka trimethylglycene) with GAA in a 4:1 (betaine: GAA) ratio.
Ostojic SM, Niess B, Stojanovic M, et al. Creatine metabolism and safety profiles after six-week oral guanidinoacetic acid administration in healthy humans. Int J Med Sci. 2013;10:141–147.
Ostojic SM, Stojanovic MD, Hoffman JR. Six-Week Oral Guanidinoacetic Acid Administration Improves Muscular Performance in Healthy Volunteers. J Investig Med. 2015 Jun 15. [Epub ahead of print]
Preworkout supplements represent some of the hottest-selling products in the industry. This stands to reason since they are a convenient, affordable, and simple way to prime the body with science-backed energizing and strength-/growth-promoting supplements. Although many of the ingredients in pre-workout formulas have been studied independently, less is known of the safety and efficacy of these multi-ingredient products when taken over longer periods of time.
A study published in Nutrition Research provides the latest data supporting the safety and efficacy of a pre-workout blend containing caffeine (300 mg/serving), creatine (5 g/serving), beta-alanine (4 g/serving), branched-chain amino acids (6 g/serving), and citrulline malate (1.5 g/serving). The researchers reported that consuming this pre-workout cocktail for 28 days straight (on training and non-training days) did not negatively impact liver, kidney, and cardiovascular health. In fact, those who took the pre-workout had far greater gains in fat-free mass and strength (leg press 1RM) versus those who took a placebo.
ACTION POINT: Choose a pre-workout product that lists its individual ingredients and doses. Remember, you get what you pay for— high-quality products tend to cost a little more, but you will benefit in the long run. Since formulations vary from product to product, always take as directed on the label.
Kendall KL, Moon JR, Fairman CM, Spradley BD, Tai CY, Falcone PH, Carson LR, Mosman MM, Joy JM, Kim MP, Serrano ER, Esposito EN. Ingesting a pre-workout supplement containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days is both safe and efficacious in recreationally active men. Nutr Res. 2014 May;34(5):442-9.
The ongoing search for the best nitric oxide booster
Nitric oxide (NO) is one of the body’s most potent vasodilators and, as such, is a key player in increasing and maintaining blood flow to skeletal muscle. NO is produced by a few mechanisms in the body—one of which occurs when l-arginine and oxygen react with endothelial nitric oxide synthase (eNOS), another mechanism is occurs with reduction of inorganic nitrate. Increased NO production allows for greater blood flow to muscles and organs, which promotes increased muscle pumps and vascularity, increased flushing of muscle metabolites and replenished nutrients, removal of free radicals, and increased oxygen delivery. Taken together, increased NO production optimizes the skeletal muscle environment for anabolism.
NO boosters have been on the market for several years and are a main ingredient in many pre-workout formulations. Over the years, science has shown that several “claimed” NO boosters work well, not so well, or no at all—this has led to ongoing research aimed at finding the ideal supplement or combination of supplements that undeniably promote increased NO production in humans.
A recent multi-phase study published in the Journal of the International Society for Sports Nutrition investigated the effectiveness of L-citrulline and/or glutathione (a potent antioxidant) on markers indicative of NO synthesis under in vivo conditions with rodents and humans and also in an in vitro condition. The most relevant findings came from the human phase of the study, which showed that stacking L-citrulline and glutathione significantly increased markers of NO production, which were most notable 30 minutes post-exercise. Notably, no other conditions boosted markers of NO and, if anything, post-exercise NO production diminished (from baseline levels) in the placebo condition.
ACTION POINT: Based on the findings from this study, stack 2g of L-citrulline with 200mg of glutathione 60 minutes before training. On non-training days take the same stack in the evening before bed.
McKinley-Barnard S, Andre T, Morita M, Willoughby DS Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis. J Int Soc Sports Nutr. 2015 Jun 10;12:27.