Creatine is classified as a "dietary supplement" under the 1994 Dietary Supplement Health and Education Act and is available without a prescription. Creatine is not subjected to FDA testing, and the purity and hygienic condition of commercial creatine products may be questionable [21]. A 1998 FDA report lists 32 adverse creatine-associated events that had been reported to FDA. These include seizure, vomiting, diarrhea, anxiety, myopathy, cardiac arrhythmia, deep vein thromboses and death. However, there is no certainty that a reported adverse event can be attributed to a particular product [22]. A recent survey of 28 male baseball players and 24 male football players, ages 18 to 23, found that 16 (31%) experienced diarrhea, 13 (25%) experienced muscle cramps, 7 (13%) reported unwanted weight gain, 7 (13%) reported dehydration, and 12 reported various other adverse effects [23].
When creatine supplementation is combined with heavy resistance training, muscle insulin like growth factor (IGF-1) concentration has been shown to increase. Burke et al [2] examined the effects of an 8 week heavy resistance training protocol combined with a 7 day creatine loading protocol (0.25 g/d/kg lean body mass) followed by a 49 day maintenance phase (0.06 g/kg lean mass) in a group of vegetarian and non-vegetarian, novice, resistance trained men and women. Compared to placebo, creatine groups produced greater increments in IGF-1 (78% Vs 55%) and body mass (2.2 Vs 0.6 kg). Additionally, vegetarians within the supplemented group had the largest increase of lean mass compared to non vegetarian (2.4 and 1.9 kg respectively). Changes in lean mass were positively correlated to the modifications in intramuscular total creatine stores which were also correlated with the modified levels of intramuscular IGF-1. The authors suggested that the rise in muscle IGF-1 content in the creatine group could be due to the higher metabolic demand created by a more intensely performed training session. These amplifying effects could be caused by the increased total creatine store in working muscles. Even though vegetarians had a greater increase in high energy phosphate content, the IGF-1 levels were similar to the amount observed in the non vegetarian groups. These findings do not support the observed correlation pattern by which a low essential amino acid content of a typical vegetarian diet should reduce IGF-1 production [33]. According to authors opinions it is possible that the addition of creatine and subsequent increase in total creatine and phosphocreatine storage might have directly or indirectly stimulated production of muscle IGF-I and muscle protein synthesis, leading to an increased muscle hypertrophy [2].

Carducci, C., Birarelli, M., Leuzzi, V., Carducci, C., Battini, R., Cioni, G., and Antonozzi, I. Guanidinoacetate and creatine plus creatinine assessment in physiologic fluids: an effective diagnostic tool for the biochemical diagnosis of arginine:glycine amidinotransferase and guanidinoacetate methyltransferase deficiencies. Clin Chem 2002;48(10):1772-1778. View abstract.
How to maximize its effects: Take 20 grams of whey protein powder in the 30 minutes before working out, and take 40 grams within 60 minutes after training. Also consider taking 20-40 grams of whey immediately upon waking every morning to kick-start muscle growth. Your best bet is to choose a whey powder that contains whey protein hydrolysates (whey protein broken down into smaller fragments for faster digestion) or whey protein isolate.
Yes, you can pack on size while only doing bodyweight exercises – I did it while traveling the world – and gymnasts train mostly with bodyweight movements. However, this can feel like playing Halo on Legendary difficulty. It can be done, but damn it can be challenging – especially for lower body movements. If your sole goal is to get bigger as fast as possible, access to a barbell for squats and deadlift is almost a requirement.
A retrospective study [81], that examined the effects of long lasting (0.8 to 4 years) CM supplementation on health markers and prescribed training benefits, suggested that there is no negative health effects (including muscle cramp or injuries) caused by long term CM consumption. In addition, despite many anecdotal claims, it appears that creatine supplementation would have positive influences on muscle cramps and dehydration [82]. Creatine was found to increase total body water possibly by decreasing the risk of dehydration, reducing sweat rate, lowering core body temperature and exercising heart rate. Furthermore, creatine supplementation does not increase symptoms nor negatively affect hydration or thermoregulation status of athletes exercising in the heat [83,84]. Additionally, CM ingestion has been shown to reduce the rate of perceived exertion when training in the heat [85].
The first open label trial on ALS failed to significantly alter lung function as assessed by FEV (when comparing the rate of decline pretreatment relative to treatment).[545] Creatine has elsewhere failed to benefit lung function at 5g daily for months relative to control[546] and failed to significantly attenuate the rate of lung function deterioration over 16 months at 10g daily[505] and 5g daily over nine months.[507]
"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.
Isometric exercise provides a maximum amount of resistance based on the force output of the muscle, or muscles pitted against one another. This maximum force maximally strengthens the muscles over all of the joint angles at which the isometric exercise occurs. By comparison, weight training also strengthens the muscle throughout the range of motion the joint is trained in, but only maximally at one angle, causing a lesser increase in physical strength at other angles from the initial through terminating joint angle as compared with isometric exercise. In addition, the risk of injury from weights used in weight training is greater than with isometric exercise (no weights), and the risk of asymmetric training is also greater than with isometric exercise of identical opposing muscles.

The creatine transporter is a sodium[139][140] and chloride[141][142] dependent membrane-associated transporter that belongs to the Na+/Cl-dependent family of neurotransmitter transporters.[143] In muscle cells and most other cell types,[131][141] the isomer of the creatine transporter is known as SLC6A8 (solute carrier family 6, member 8). SLC6A8 is encoded by the gene present on the Xq28 region of the human X-chromosome and is expressed in most tissues.[144] A related gene encoding a creatine transporter variant has also been identified at 16p11.1 that is expressed exclusively in the testes.[145] These two transporters share 98% homology.[144][145]

In recent years, the related areas of fitness and figure competition have increased in popularity, surpassing that of female bodybuilding, and have provided an alternative for women who choose not to develop the level of muscularity necessary for bodybuilding. McLish would closely resemble what is thought of today as a fitness and figure competitor, instead of what is now considered a female bodybuilder. Fitness competitions also have a gymnastic element to them. A study by the Clinical Journal of Sport Medicine found that female bodybuilders who are taking anabolic steroids are more likely to have qualified for substance dependence disorder, to have been diagnosed with a psychiatric illness, or to have a history of sexual abuse.[14]

In addition to the proper amount of sleep, do not overdo your training regimen. While you might be tempted to think that "more is better," in fact the opposite is true. You can reach a point known as "over-training", in which you'll lose the ability to "pump" (engorge the muscles with oxygen-rich blood) your muscles, and this can even lead to muscle wasting—exactly the opposite of what you are trying to achieve. Here are some symptoms to be aware of if you think you may be falling into the over-training zone:
Do a single set of repetitions. Theories on the best way to approach weight training abound, including countless repetitions and hours at the gym. But research shows that a single set of exercise with a weight that fatigues your muscle after about 12 to 15 repetitions can build muscle efficiently in most people and can be as effective as three sets of the same exercise.
Squats target both your inner and outer thighs. Use a barbell heavy enough to challenge your muscles but light enough that you can still control your form. Hold it behind your head with your feet shoulder-width apart. Tighten your core, then squat down as far as comfortable. There should be no knee or back pain. As you come back up, raise your hips and chest together.
Using too much weight, too soon; always start lower than your expected ability and work your way up that first workout. If your form suffers, you are swinging the weight, or using momentum, this indicates you may be using too much weight. Greater momentum increases the potential for injury and reduces the effectiveness to the muscle group being targeted.