In people with COPD given either glucose placebo (40.7g) or creatine supplementation (5.7g creatine with 35g glucose) thrice daily for two weeks followed by a single dose for ten weeks, supplementation was associated with improvements in muscular strength and endurance, but not cardiovascular exercise potential.[579] A later trial of larger power using a loading phase of 22g creatine with a maintenance phase of 3.76g during rehabilitative exercise failed to replicate the improvements in skeletal muscle performance despite increased body weight seen with creatine,[580] and the failure to improve cardiovascular performance during aerobic exercise seen in both aforementioned studies has been replicated elsewhere after eight weeks supplementation, during which muscular performance was, again, unaffected.[581]

Creatine is most commonly used for improving exercise performance and increasing muscle mass in athletes and older adults. There is some science supporting the use of creatine in improving the athletic performance of young, healthy people during brief high-intensity activity such as sprinting. Because of this, creatine is often used as a dietary supplement to improve muscle strength and athletic performance. In the U.S., a majority of sports nutrition supplements, which total $2.7 billion in annual sales, contain creatine.


Chin-Ups. The chin-up is the easiest way to determine someone’s relative strength. If you can knock out sets of bench with your bodyweight but can’t perform at least 5 bodyweight chin-ups then it’s time to re-evaluate your priorities. Chin-ups are an excellent mass builder for the lats, biceps, and upper back so they should take the place of machine variations like lat pulldowns whenever possible.
If you’re exercising at your maximum intensity, your body literally can’t produce enough ATP to keep up. (10) That’s where creatine supplements come in: They can help increase your body’s stores of phosphocreatine (an organic compound of creatine and phosphoric acid that’s stored in your muscle tissue) to produce new ATP during high-intensity exercise.
"Eating well" is tough to objectively quantify. One can eat "well" but that doesn't necessarily mean that you are eating enough to build muscle or recover adequately from workouts. Also, taking protein shakes doesn't guarantee that one will start to accrue massive slabs of lean body mass. Muscle anabolism is a fairly complex metabolic process which has a number of contributing factors at the cellular level and can't be reduced to a single supplement or dietary component.

It’s perhaps best known for the aesthetic benefits. Creatine increases muscle size relatively quickly and while that’s in part due to an increase in muscle water content — a good thing, since it means we’re better hydrated — it does indeed appear to lead to actual hypertrophy over time. And bigger muscles aren’t just aesthetic: larger muscles can improve work capacity, explosiveness, fat oxidation, injury resilience, and recovery.
The type of exercise performed also depends on the individual's goals. Those who seek to increase their performance in sports would focus mostly on compound exercises, with isolation exercises being used to strengthen just those muscles that are holding the athlete back. Similarly, a powerlifter would focus on the specific compound exercises that are performed at powerlifting competitions. However, those who seek to improve the look of their body without necessarily maximizing their strength gains (including bodybuilders) would put more of an emphasis on isolation exercises. Both types of athletes, however, generally make use of both compound and isolation exercises.
When looking specifically at human studies, there has been a failure of creatine supplementation to induce or exacerbate kidney damage in people with amyotrophic lateral sclerosis (ALS). Subjects do not experience kidney damage for up to or over a year’s worth of supplementation in the 5-10g range.[505][506][507] Postmenopausal women,[517] people with type II diabetes,[518] people on hemodialysis,[313] otherwise healthy elderly,[519] young people,[454][520][521] and athletes do not experience kidney damage either.[324] Moreover, numerous scientific reviews on both the long- and short-term safety of supplemental creatine have consistently found no adverse effects on kidney function in a wide range of doses.[522][523][524][452][525][451][526][527] However, while doses >10 g/day have been found not to impair kidney function, there are fewer long-term trials using such high chronic daily intakes.[527]
More recent studies on the regulation of CrT creatine transport activity have identified the protein kinase (Janus-Activating Kinase 2) JAK2, which suppresses the rate of creatine uptake via CrT without affecting creatine binding.[181] JAK2 is a regulatory protein involved in stabilizing the cellular membrane and controlling water concentrations in response to osmotic stress.[182][183] Similar to c-Src (a positive creatine transport regulator), Jak2 can also be activated by growth hormone signaling.[169][184] The growth hormone receptor seems to activate these two factors independently, as gh-mediated activation of c-Src does not require JAK2.[168] Given that c-Src is a positive regulator of CrT, JAK2 is a negative regulator, and the fact that downstream signals from both are induced by growth hormone, it is tempting to speculate that JAK2 activation downstream of the gh receptor may function as a homeostatic response to limit c-src induced creatine uptake. This has not been studied, however, and the effects of gh-induced JAK2 signaling on CrT activity have not been examined.
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The bodybuilding community has been the source of many weight training principles, techniques, vocabulary, and customs. Weight training does allow tremendous flexibility in exercises and weights which can allow bodybuilders to target specific muscles and muscle groups, as well as attain specific goals. Not all bodybuilding is undertaken to compete in bodybuilding contests and, in fact, the vast majority of bodybuilders never compete, but bodybuild for their own personal reasons.
There is a nuclear receptor known as TIS1 (orphan receptor, since there are no known endogeouns targets at this time) which positively influences transcription of new creatine transporters[171] and, in C2C12 myotubes, seems to be responsive to cAMP or adenyl cyclase stimulation from forskolin (from Coleus Forskohlii) with peak activation at 20µM.[171][172] 
One case study exists of a man with focal segmental glomerulosclerosis who experienced an accelerated rate of GFR decline during supplementation (5g thrice daily for loading, then a 2g maintenance for seven weeks) which was partially reversed upon supplement cessation. This was deemed strong circumstantial evidence, and the brand of supplement was not named.[616] Elsewhere, interstitial nephritis associated with creatine supplementation has been reported in a man, although symptoms arose four weeks after supplementation started with no evidence to support correlation.[617] Some studies involving athletes and various dietary supplements have attempted to draw a correlation with creatine and cases of rhabdomyolysis.[618][619][620][621] Finally, one study in a diabetic person ingesting both metformin and creatine resulting in metabolic acidosis has attempted to place causation on creatine, but it did not establish causation or circumstantial evidence.[622] 
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