The majority of creatine in the human body is in two forms, either the phosphorylated form making up 60% of the stores or in the free form which makes up 40% of the stores. The average 70 kg young male has a creatine pool of around 120-140 g which varies between individuals [10,11] depending on the skeletal muscle fiber type [1] and quantity of muscle mass [11]. The endogenous production and dietary intake matches the rate of creatinine production from the degradation of phosphocreatine and creatine at 2.6% and 1.1%/d respectively. In general, oral creatine supplementation leads to an increase of creatine levels within the body. Creatine can be cleared from the blood by saturation into various organs and cells or by renal filtration [1].
Some of these athletes take it to an unhealthy — and in some cases illegal — extreme with anabolic steroids, prohormones, diuretics, and potentially harmful substances. In addition to their potential performance-enhancing attributes, many of these substances also can have serious and significant side effects. A telling example of this is the story of ephedra — a once widely-used supplement for bodybuilding that has since been banned and removed from the market due to multiple reports of life-threatening side effects and death after its use.
A study showed that 100mg/kg creatine monohydrate daily over four months supplemented by boys with DMD is able to enhance handgrip strength in the dominant hand only (less than 10% increase) and increase whole-body lean mass. While the trend toward whole body strength reduction seen in placebo was ablated and there was no interaction with corticosteroids,[560] this study failed to find an influence on activities of daily living or lung function.[560] Elsewhere in children not on corticosteroids with DMD, supplementation of 5g creatine for eight weeks was confirmed to increase muscular phosphocreatine content[554] and according to a manual muscle test (MMT) there was a significant improvement in muscular function relative to placebo, with more parents reporting benefit with creatine (53.8%) relative to placebo (14%).[554]
One of the studies noting a reduction in fatigue in healthy subjects given creatine (8g) for five days prior to a mathematical test noted a relative decrease in oxygenation hemoglobin in the brain and an increase in deoxygenated hemoglobin, which normally indicates a reduction in cerebral oxygenation.[245] The authors made note of how cytoplasmic phosphocreatine can increase oxygen uptake into cells (noted in vitro in a concentration dependent manner between 0-25mM[245]) and suggested that either cells were taking up more oxygen from hemoglobin, or that increased mitochondrial efficiency resulted in less of a need for oxygen.[245]

Creatine is stored in the body in the form of creatine and as creatine phosphate, otherwise known as phosphocreatine, which is the creatine molecule bound to a phosphate group.[39] Creatine phosphate is thought to maintain the ATP/ADP ratio by acting as a high-energy phosphate reservoir.[40] The more ATP a muscle has relative to ADP, the higher its contractility is, and thus its potential strength output in vivo.[41][42] This pro-energetic mechanism also affects nearly all body systems, not just skeletal muscle. [39] During periods of rest and anabolism, creatine can gain a phosphate group through the creatine-kinase enzyme pathway, up to a cellular concentration of 30uM[24] to be later used for quick ATP resupply, when needed.[43][44] 
In regard to practical interventions, concurrent glycogen loading has been noted to increase creatine stores by 37-46% regardless of whether the tissue was exercised prior to loading phase.[176] It is important to note, however, that creatine levels in response to the creatine loading protocol were compared in one glycogen-depleted leg to the contralateral control leg, which was not exercised.[176] This does not rule out a possible systemic exercise-driven increase in creatine uptake, and the increase in creatine noted above[176] was larger than typically seen with a loading protocol (usually in the 20-25% range). Consistent with an exercise-effect, others have reported that exercise itself increases creatine uptake into muscle, reporting 68% greater creatine uptake in an exercised limb, relative to 14% without exercise.[153]
“Reg Park’s theory was that first you have to build the mass and then chisel it down to get the quality; you work on your body the way a sculptor would work on a piece of clay or wood or steel. You rough it out””the more carefully, the more thoroughly, the better”” then you start to cut and define. You work it down gradually until it’s ready to be rubbed and polished. And that’s when you really know about the foundation. Then all the faults of poor early training stand out as hopeless, almost irreparable flaws. [..]
Weight training also provides functional benefits. Stronger muscles improve posture, provide better support for joints, and reduce the risk of injury from everyday activities. Older people who take up weight training can prevent some of the loss of muscle tissue that normally accompanies aging—and even regain some functional strength—and by doing so, become less frail.[33] They may be able to avoid some types of physical disability. Weight-bearing exercise also helps to prevent osteoporosis.[34] The benefits of weight training for older people have been confirmed by studies of people who began engaging in it even in their eighties and nineties.
K. Aleisha Fetters, M.S., C.S.C.S., is a Chicago-based personal and online trainer. She has a graduate degree in health and science reporting from the Medill School of Journalism at Northwestern University and regularly contributes to Men's Health, Women's Health, USNews.com, TIME, and SHAPE. When she's not lifting something heavy, she's usually guzzling coffee and writing about the health benefits of doing so.
Creatine is mostly synthesized in the liver via AGAT and GAMT[28][32] (the other locations are neurons,[34] the pancreas, and kidneys[33]) despite it not being stored in high levels in the liver like glycogen or adipose would be. Supplemental creatine is known to suppress AGAT by downregulating transcription,[30] which probably occurs in humans (since the products of AGAT are reduced with creatine supplementation).[38]

Every gym has a guy shaped like a lightbulb. He's the one who neglects his lower body. If you don't want to be that guy, work your major leg muscles on the leg press machine. Place your feet on the plate with knees bent at 90 degrees. Grasp the handles and slowly push the plate out until your knees are straight but not locked. Pause and slowly return to the starting spot.
First off, every single resistance-training athlete in the world should be very thankful for bodybuilding training. It was bodybuilding that brought weight training to the mainstream. The bottom line is that the average gym goer is MORE interested in how they look vs. how they perform. 99% of every client I ever trained had an aesthetic goal as their primary goal. In my 20 plus years as a trainer I can count maybe 10 clients who said, “My goal is to be able to bench press or squat or lift more weight.” It was the aesthetic focus of bodybuilding that opened the doors for all other resistance training pursuits to enter into the mainstream.
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] 
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. 

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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.
Peirano, R. I., Achterberg, V., Dusing, H. J., Akhiani, M., Koop, U., Jaspers, S., Kruger, A., Schwengler, H., Hamann, T., Wenck, H., Stab, F., Gallinat, S., and Blatt, T. Dermal penetration of creatine from a face-care formulation containing creatine, guarana and glycerol is linked to effective antiwrinkle and antisagging efficacy in male subjects. J.Cosmet.Dermatol. 2011;10(4):273-281. View abstract.
After a tough sweat, it's important to rehydrate your body: "Drink lots of water and thank your body for what it was just able to accomplish," says Davis. A balanced post-workout snack is also a good idea. Go for one with carbs refuel your glycogen stores (one of your body's main energy sources) and about 10 to 20 grams of protein to help build and repair your muscles. "Don’t overcomplicate it," says Davis. If you're lifting and weight loss is one of your goals, though, it's still important to keep calories in mind—a post-workout snack shouldn't be more than 150 to 200 calories. Here's a guide to how many calories you should be eating for weight loss.
Although weight training is similar to bodybuilding, they have different objectives. Bodybuilders use weight training to develop their muscles for size, shape, and symmetry regardless of any increase in strength for competition in bodybuilding contests; they train to maximize their muscular size and develop extremely low levels of body fat. In contrast, many weight trainers train to improve their strength and anaerobic endurance while not giving special attention to reducing body fat far below normal.
Incubation of a β-cell with additional creatine (5-10mM), even at saturated concentrations of glucose, is able to further increase insulin secretion in response to glucose, specifically as the leucine metabolite 2-ketoisocaproic acid, potassium, and a potassium channel blocker were all ineffective.[494] This has been found to occur in rats given 2% of the diet as creatine[345] but has since failed in humans given 5g of creatine.[351]
Prohormones are precursors to hormones and are most typically sold to bodybuilders as a precursor to the natural hormone testosterone. This conversion requires naturally occurring enzymes in the body. Side effects are not uncommon, as prohormones can also convert further into DHT and estrogen. To deal with this, many supplements also have aromatase inhibitors and DHT blockers such as chrysin and 4-androstene-3,6,17-trione. To date most prohormone products have not been thoroughly studied, and the health effects of prolonged use are unknown. Although initially available over the counter, their purchase was made illegal without a prescription in the US in 2004, and they hold similar status in many other countries. They remain legal, however, in the United Kingdom and the wider European Union. Their use is prohibited by most sporting bodies.
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] 
These effects were noted before in a preliminary study of depressed adolescents (with no placebo group) showing a 55% reduction in depressive symptoms at 4g daily when brain phosphocreatine levels increased.[231] Other prelimnary human studies suggest creatine might lessen unipolar depression[256] and one study on Post-Traumatic Stress Disorder (PTSD) noted improved mood as assessed by the Hamilton Depression Rating Scale.[232]
^ Jump up to: a b c d e Cooper R, Naclerio F, Allgrove J, Jimenez A (July 2012). "Creatine supplementation with specific view to exercise/sports performance: an update". Journal of the International Society of Sports Nutrition. 9 (1): 33. doi:10.1186/1550-2783-9-33. PMC 3407788. PMID 22817979. Creatine is produced endogenously at an amount of about 1 g/d. Synthesis predominately occurs in the liver, kidneys, and to a lesser extent in the pancreas. The remainder of the creatine available to the body is obtained through the diet at about 1 g/d for an omnivorous diet. 95% of the bodies creatine stores are found in the skeletal muscle and the remaining 5% is distributed in the brain, liver, kidney, and testes [1].
Put simply, "strength training means using resistance to create work for your muscles," says Hannah Davis, C.S.C.S. and author of Operation Bikini Body. So even if your mind jumps straight to those hardcore machines and massive weights, there are a lot of ways to create this resistance that require minimal equipment (or none at all). Bodyweight workouts can be an incredibly effective way to strength train. Squats and push-ups FTW. You can also use tools like dumbbells, medicine balls, TRX bands, resistance bands, kettlebells, and slider disks, to help get the job done, explains Davis. But if that sounds like gibberish don't worry about it. Keep it simple and focus on equipment-free routines first. No matter what you do, the most important thing is to find something that challenges you, says Davis.
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]
For example, a 2015 review published in the peer-reviewed journal Applied Physiology, Nutrition, and Metabolism suggests that, for maximal muscle growth, people consume 25 to 35 grams of protein at breakfast, lunch and dinner. You'll find that amount of protein in a chicken breast, a cup of Greek yogurt with slivered almonds or about a three-quarter block of tofu.
Cyclocreatine appears to be passively diffused through membranes and not subject to the creatine transporter, which can be beneficial for cases where creatine transporter function is compromised (creatine non-response and SLG6A8 deficiency). Similar to other forms of creatine, it buffers ATP concentrations, although its efficacy as a supplement in otherwise healthy people is currently unknown.
Without supplementation, approximately 14.6mmol (2g) of creatinine, creatine’s urinary metabolite, is lost on a daily basis in a standard 70kg male ages 20-39. The value is slightly lower in females and the elderly due to a presence of less muscle mass.[35] This amount is considered necessary to obtain in either food or supplemental form to avoid creatine deficiency. Requirements may be increased in people with higher than normal lean mass.[35][198] Creatine excretion rates on a daily basis are correlated with muscle mass, and the value of 2g a day is derived from the aforementioned male population with about 120g creatine storage capacity.[35] Specifically, the rate of daily creatine losses is about 1.6%[199]-1.7%,[25] and mean losses for women are approximately 80% that of men due to less average lean mass.[35] For weight-matched elderly men (70kg, 70-79 years of age) the rate of loss of 7.8mmol/day,[49] or about half (53%) that of younger men.

JAK2 (Janus-Activating Kinase 2) is a novel protein that has been shown to suppress the activity of the creatine transporter CrT in vitro. The effects of JAK2 on CrT are not well-understood in vivo, however. Given that growth hormone activates both c-src (increases CrT activity) and JAK2- which has been found to decrease CrT activity, it is plausible that JAK2 may function as a negative-feedback regulator of creatine uptake. Future research is needed to better understand the role of JAK2 on CrT activity in vivo.
1. Train each muscle group twice per week. To maximize muscle growth, plan to train every major muscle group at least twice per week. According to a 2016 Sports Medicine review, even if you don't work that muscle any harder or longer, by simply dividing your chest, leg or back workout into two days, you'll spur more muscle growth. While the jury is still out on whether training each muscle group three days per week is better than two at spurring hypertrophy, it is likely better suited toward experienced lifters than beginners, Matheny says.
One case study on a subject with a methylentetrahydrofolate reductase (MTHFR) 677TT homozygote, a relatively common genetic mutation known as “mild MTHFR deficiency,” which causes mild homocysteinemia,[310] has seen benefits due to creatine supplementation where homocysteine was approximately halved (49% reduction) while CT heterozygotes and CC homozygotes (n=9) were unaffected.[311] Additionally, one rat study suggested a possible role for creatine in reducing homocysteine levels in a model of high uric acid levels (model for end stage renal disease[312]) but this was not replicated when investigated in humans.[313]
It is equally important, if not more so, to ensure that you supply your body with more protein than it is breaking down each day. Your body uses protein for many things daily, and when you are working out, your body may start to break down proteins to provide extra energy. But your body also requires proteins to create new muscle cells and repair damaged ones. Many bodybuilding supplements contain large amounts of protein to ensure that your body has plenty for all required processes. Jump to Our 10 Best Bodybuilding Supplement List
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