After the ingestion of 5g creatine in otherwise healthy humans, serum levels of creatine were elevated from fasting levels (50-100µM) to 600-800µM within one hour after consumption.[135] The receptor follows Michaelis-Menten kinetics with a Vmax obtained at concentrations higher than 0.3-0.4mmol/L,[136] with prolonged serum concentrations above this amount exerting most of its saturation within two days.[137]
Once training is resumed under these conditions, there may be little in the way of caloric support to ensure that protein synthesis and muscle growth occurs. Muscle may even begin to cannibalize itself as the body enters into a catabolic state. Even with the best of diets this can sometimes happen if training demands override the nutritional balance or imbalance.
Small but significant is good. It’s especially helpful during short periods of extremely powerful physical activity, particularly if those short bursts of activity are repeated, as in weightlifting, sprinting or football, for example. The study also says that creatine supplementation is associated with enhanced strength gains in strength training programs, which could be related to the greater volume and intensity of training that you can achieve when you’re taking creatine supplements. Plus, according to the study, there’s no evidence of gastrointestinal, renal or muscle cramping complications – more good news.
Over time, we naturally lose muscle mass in a process called sarcopenia. On average, men lose about 30% of their muscle mass during their lives. Usually, this begins in your 30s and progresses slowly as you age. But, don’t despair. You can rebuild and maintain muscle mass even as you age. Often, diet and exercise are enough. But, sometimes, if the above hormones play a role, your doctor may recommend medications and additional treatments (4).
In addition to the HIIT sessions, it’s always a good idea to go for a 30–60-minute walk as many days per week as you can. I recommend getting a minimum of 10,000 steps every day. Use a phone app to track them. If you’re into jogging, swimming, hiking, or some other form of long-duration, fairly low-intensity cardio, that is fine to do as well, and as often as you like.
Supplementation of a loading phase of creatine has been noted to augment the increase in RBC levels of superoxide dismutase (SOD) from exercise, when measured immediately after, by 8.1%, but control groups increased to match within an hour.[299] Glutathione (normally decreases with exercise) and catalase (increases) were both unaffected,[299] and elsewhere in vitro red blood cells incubated with 3mM of creatine (within the supplemental range) is able to improve filterability (a measure of cell rheology, or fluid structure of the cell[300]) when RBC creatine was increased by 12.3% to reach 554µM.[301] This was thought to be due to reduced oxidative stress (assessed via MDA) in the red blood cells, which in the presence of 1-5mM creatine was progressively reduced by 20-41%.[301]
Heath has 1.8 million Instagram followers, 300,000 Twitter followers, a global fan base and a growing portfolio of muscle magazine covers. He competes in just one competition a year, Mr. Olympia, for which he won the $400,000 first prize this year. He spends the rest of the year staying in shape and flying hundreds of thousands of miles for appearances, conferences and meetings. He has five sponsors, led by Ultimate Nutrition, a supplement company. All told, he earns more than $1 million a year, his agent said.

The muscle endurance objective is pursued when you want your muscles to be able to perform the same motions over an extended period of time or in other words when you want your muscles to be strong and not become tired rapidly. You'll want to use at least 4 sets from which at least 16 repetitions are performed. The muscle endurance objective is often used for muscles in your lower body, such as those located in your legs or your buttocks.
A typical creatine supplementation protocol consists of a loading phase of 20 g CM/d or 0.3 g CM/kg/d split into 4 daily intakes of 5 g each, followed by a maintenance phase of 3-5 g CM/d or 0.03 g CM/kg/d for the duration of the supplementation period [5]. Other supplementation protocols are also used such as a daily single dose of around 3 – 6 g or between 0.03 to 0.1 g/kg/d [15,55] however this method takes longer (between 21 to 28 days) to produce ergogenic effects [5]. Sale et al [56] found that a moderate protocol consisting of 20 g CM taken in 1g doses (evenly ingested at 30-min intervals) for 5 days resulted in reduced urinary creatine and methylamine excretion, leading to an estimated increase in whole body retention of creatine (+13%) when compared with a typical loading supplementation protocol of 4 x 5 g/d during 5 days (evenly ingested at 3 hour intervals). This enhancement in creatine retention would lead to a significantly higher weight gain when people follow a moderate protocol ingestion of several doses of small amounts of CM evenly spread along the day. 

Creatine monohydrate is the most common form of creatine, and if not otherwise mentioned is the default form of creatine used in most studies on creatine.[64] It has fairly decent intestinal absorption[65][12] (covered more in depth in the pharmacology section) and is the standard form or “reference” form of creatine, which all other variants are pitted against.

During the 1950s, the most successful and most famous competing bodybuilders[according to whom?] were Bill Pearl, Reg Park, Leroy Colbert, and Clarence Ross. Certain bodybuilders rose to fame thanks to the relatively new medium of television, as well as cinema. The most notable[according to whom?] were Jack LaLanne, Steve Reeves, Reg Park, and Mickey Hargitay. While there were well-known gyms throughout the country during the 1950s (such as Vince's Gym in North Hollywood, California and Vic Tanny's chain gyms), there were still segments of the United States that had no "hardcore" bodybuilding gyms until the advent of Gold's Gym in the mid-1960s. Finally, the famed Muscle Beach in Santa Monica continued its popularity as the place to be for witnessing acrobatic acts, feats of strength, and the like. The movement grew more in the 1960s with increased TV and movie exposure, as bodybuilders were typecast in popular shows and movies.[citation needed]
In young rats given creatine in the diet at 2% of the diet for eight weeks, supplementation appears to increase bone mineral density (BMD) in the lumbar spine with a nonsignificant trend to increase BMD in the femur.[426] Despite the trend, the femur appeared to be 12.3% more resistant to snapping from mechanical stress associated with increased thickness.[426] Menopausal rats (ovarectomized) experience similar benefits, as supplementation of creatine (300mg/kg) for eight weeks during ovarectomy is able to increase phosphorus content of the bone and other biomarkers of bone health, although bone stress resistance was not tested.[427]

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]