Cyclocreatine (1-carboxymethyl-2-iminoimidazolidine) is a synthetic analogue of creatine in a cyclic form. It serves as a substrate for the creatine kinase enzyme system, acting as a creatine mimetic. Cyclocreatine may compete with creatine in the CK enzyme system to transfer phosphate groups to ADP, as coincubation of both can reduce cyclocreatine’s anti-motility effects on some cancer cells.[96]
“There is a lot of mixed research on creatine’s ability to improve muscle strength,” the government website says. “However, analyses of this research show that creatine seems to modestly improve upper body strength and lower body strength in both younger and older adults.” Creatine has also been shown to improve athletes’ performance in rowing, soccer, and jumping height.
I get lost every time I walk into my neighborhood GNC… the people who work there know their stuff, but nobody knows my body better than me and that’s where it all falls apart, but I’m working on that. I agree, I rather have grass-fed and more natural options as opposed to anything containing GMO in the products… The point is to become healthier, not go the other way…. But I also don’t want to get too much soy in my diet either… My wife is doesn’t want it for me and it’s given me headaches too, so I’m not really one for those. I guess small amounts of soy should be okay, right? Could someone be allergic to soy? There’s tons of other options though and I’m going to have to really look more into these here coz it has everything I’ve been looking for! Thanks for putting this together!
A maintenance phase of 2g daily appears to technically preserve creatine content in skeletal muscle of responders either inherently or after a loading phase, but in sedentary people or those with light activity, creatine content still progressively declines (although it still higher than baseline levels after six weeks) and glycogen increases seem to normalize. This maintenance dose may be wholly insufficient for athletes, a 5g maintenance protocol may be more prudent.
Without supplementation, creatine is formed primarily in the liver, with minor contributions from the pancreas and kidneys. The two amino acids, glycine and arginine, combine via the enzyme Arginine:Glycine amidinotransferase (AGAT) to form ornithine and guanidoacetate. This is the first of two steps in creatine synthesis, and although rare, any deficiency of this enzyme can result in mild mental retardation and muscular weakness.[28] AGAT is also the primary regulatory step, and an excess of dietary creatine can suppress activity of AGAT to reduce creatine synthesis[29] by reducing AGAT mRNA levels, rather than resulting in competitive inhibition.[30]
Creatine is a hydrophilic polar molecule that consists of a negatively charged carboxyl group and a positively charged functional group [64]. The hydrophilic nature of creatine limits its bioavailability [65]. In an attempt to increase creatines bioavailability creatine has been esterified to reduce the hydrophilicity; this product is known as creatine ethyl ester. Manufacturers of creatine ethyl ester promote their product as being able to by-pass the creatine transporter due to improved sarcolemmal permeability toward creatine [65]. Spillane et al [65] analyzed the effects of a 5 days loading protocol (0.30 g/kg lean mass) followed by a 42 days maintenance phase (0.075 g/kg lean mass) of CM or ethyl ester both combined with a resistance training program in 30 novice males with no previous resistance training experience. The results of this study [65] showed that ethyl ester was not as effective as CM to enhance serum and muscle creatine stores. Furthermore creatine ethyl ester offered no additional benefit for improving body composition, muscle mass, strength, and power. This research did not support the claims of the creatine ethyl ester manufacturers.