Honestly, I did a lot of research on this one, because I wanted to find a single group of people who should not strength train.  I even found studies on how strength training can be beneficial for paraplegics.  Not to mention it can be safe for children, adolescents, and pregnant women.  Obviously, you should take a break from strength training if you’re injured, and always check with your doctor before you start any sort of strength training program, but it’s natural for us, as humans, to move around and carry things.

I know this goes against the recommendations you often see in stereotypical bodybuilding routines (i.e. the ones that involve having a single “chest day” or “arm day” or “shoulder day” once a week), but that’s just one of the many reasons why those types of routines suck for us natural, genetically-average people, and work best for steroid users with great genetics.
^ Jump up to: a b c d Luckose F, Pandey MC, Radhakrishna K (2015). "Effects of amino acid derivatives on physical, mental, and physiological activities". Crit. Rev. Food Sci. Nutr. 55 (13): 1793–1807. doi:10.1080/10408398.2012.708368. PMID 24279396. HMB, a derivative of leucine, prevents muscle damage and increases muscle strength by reducing exercise-induced proteolysis in muscles and also helps in increasing lean body mass. ... The meta analysis studies and the individual studies conducted support the use of HMB as an effective aid to increase body strength, body composition, and to prevent muscle damage during resistance training.

Longer rest periods are more ideal for making progressive tension overload happen, and shorter rest periods are more ideal for generating metabolic fatigue. So, if you’re doing an exercise that is better suited for progressive overload (i.e. primary compound exercises), you’re going to want to rest longer between sets to maximize strength output. And if you’re doing an exercise that is better suited for metabolic fatigue (i.e. isolation exercises), you’re going to want to rest less between sets to make that happen. And if you’re doing an exercise that is suited equally for a combination of the two (i.e. secondary compound exercises), you’re usually going to want a moderate rest period somewhere in between.

^ Jump up to: a b c d Brosnan JT, da Silva RP, Brosnan ME (May 2011). "The metabolic burden of creatine synthesis". Amino Acids. 40 (5): 1325–31. doi:10.1007/s00726-011-0853-y. PMID 21387089. Creatinine loss averages approximately 2 g (14.6 mmol) for 70 kg males in the 20- to 39-year age group. ... Table 1 Comparison of rates of creatine synthesis in young adults with dietary intakes of the three precursor amino acids and with the whole body transmethylation flux

According to research from the University of Stirling, for optimal protein growth, weight lifters need to eat 0.25 to 0.30 grams of protein per kilogram body weight per meal. For a 175-pound person, that works out to 20 to 24 grams of protein at every meal. You’ll get that in three to four eggs, a cup of Greek yogurt, or one scoop of protein powder.
In particular situations, a coach may advise performing the valsalva maneuver during exercises which place a load on the spine. The vasalva maneuver consists of closing the windpipe and clenching the abdominal muscles as if exhaling, and is performed naturally and unconsciously by most people when applying great force. It serves to stiffen the abdomen and torso and assist the back muscles and spine in supporting the heavy weight. Although it briefly increases blood pressure, its is still recommended by weightlifting experts such as Rippetoe since the risk of a stroke by aneurysm is far lower than the risk of an orthopedic injury caused by inadequate rigidity of the torso.[10] Some medical experts warn that the mechanism of building "high levels of intra-abdominal pressure (IAP)...produced by breath holding using the Valsava maneuver", to "ensure spine stiffness and stability during these extraordinary demands", "should be considered only for extreme weight-lifting challenges — not for rehabilitation exercise".[11]

Discomfort can arise from other factors. Individuals who perform large numbers of repetitions, sets, and exercises for each muscle group may experience a burning sensation in their muscles. These individuals may also experience a swelling sensation in their muscles from increased blood flow (the "pump"). True muscle fatigue is experienced as a marked and uncontrollable loss of strength in a muscle, arising from the nervous system (motor unit) rather than from the muscle fibers themselves. Extreme neural fatigue can be experienced as temporary muscle failure. Some weight training programs, such as Metabolic Resistance Training, actively seek temporary muscle failure; evidence to support this type of training is mixed at best.[24] Irrespective of their program, however, most athletes engaged in high-intensity weight training will experience muscle failure during their regimens.
Bryant, a lawyer and sports agent, opened a case of manila file folders and spread them on the desk like playing cards. Each was labeled: Phil Heath Enterprises, Sponsors, Taxes, Travel and so on. Bryant, Heath and Cremona discussed Heath’s clothing line and his sponsorships. They talked about his desire for a shoe deal and a larger hyperbaric chamber at his house.
Related to exercise and fitness, BCAAs are taken to help reduce muscle breakdown, which is why they may be known as muscle building supplements. Leucine, in particular, is known for playing an important role in muscle protein synthesis, which can help with muscle gain and maintenance. Some also claim that BCAAs can enhance performance, although many studies also refute this claim.
ZMA: This supplement is a combination of zinc, magnesium and vitamin B-6. Some research shows that this combination can help raise testosterone levels. In the trial, subjects took a daily dose of ZMA (which included 30 mg zinc monomethionine, 450 mg magnesium aspartate and 10.5 mg vitamin B-6) at night during 7 weeks. Other hormones like IGF also increased, while the stress hormone, cortisol was reduced, creating an overall more favorable hormone profile. Not surprisingly, muscle performance also improved. (n) This paper is surrounding in controversy, however, because one of the scientists involved also holds the trademark for ZMA, and the research is company-funded.
Volek, J. S., Ratamess, N. A., Rubin, M. R., Gomez, A. L., French, D. N., McGuigan, M. M., Scheett, T. P., Sharman, M. J., Hakkinen, K., and Kraemer, W. J. The effects of creatine supplementation on muscular performance and body composition responses to short-term resistance training overreaching. Eur.J.Appl.Physiol 2004;91(5-6):628-637. View abstract.
Kornblum, C., Schroder, R., Muller, K., Vorgerd, M., Eggers, J., Bogdanow, M., Papassotiropoulos, A., Fabian, K., Klockgether, T., and Zange, J. Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind 31P-MRS crossover study. Eur J Neurol 2005;12:300-309. View abstract.
Creatine citrate is creatine bound to citric acid, or citrate. Creatine citrate does not differ greatly from monohydrate in regard to absorption or kinetics.[83] Note that creatine citrate is more water-soluble than monohydrate,[84] but creatine absorption is generally not limited by solubility. The increased water solubility may play a factor in palatability.
It may seem odd to put such a common supplement as minerals on this list, but few people are aware that minerals are enzyme activators. Many vitamins, on the other hand, are coenzymes, which means that without minerals they're useless. Many minerals, such as zinc and chromium, also interact with various anabolic hormones, such as testosterone, growth hormone and insulin.
Parashos, S. A., Swearingen, C. J., Biglan, K. M., Bodis-Wollner, I., Liang, G. S., Ross, G. W., Tilley, B. C., and Shulman, L. M. Determinants of the timing of symptomatic treatment in early Parkinson disease: The National Institutes of Health Exploratory Trials in Parkinson Disease (NET-PD) Experience. Arch Neurol. 2009;66:1099-1104. View abstract.

Some people do have allergies to soy, or they have an intolerance to soy. If you notice certain symptoms (like a headache) after soy consumption, you may have an intolerance. Discovering your food intolerances/allergies would also be handled by a Dietitian. For the general population who are not allergic/intolerant to soy, however, soy-based products can be a part of a healthy diet. New research has shown that soy is not harmful as people fear. If soy gives you issues, you could always opt for whey protein, pea protein or other forms of vegetable protein. Have you seen our article on protein powders? Click here.
Progain contains an easily digested source of carbohydrate, providing much needed carbohydrate to fuel your workout before or after. By adding creatine to your diet, in a shake, in food or in capsules, is proven to increase strength, build muscle size and support training intensity. At Maximuscle we have a number of products with added creatine, such as: Creatine Monohydrate, Creatamax Capsules, Cyclone (powder & bars), Progain Flapjack.
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]
Safety. In general health terms, most medical opinion is that up to three cups of coffee a day are not harmful, and may even have some benefits, although some people respond to the stimulant properties with more problems than others. Heart palpitations and restlessness are experienced by some caffeine drinkers. In pregnancy, one or two cups each day are thought to be without harm to the fetus.
Studies measuring extracellular water versus intracellular water note similar increases in both, associated with creatine. Creatine does not tend to disturb the ratios of water to dry mass in various tissues measured.[609] At least one study in older men (48-72 years) has failed to find a significant difference in both intracellular and extracellular water concentration after 14 weeks of 5g creatine daily (with gatorade) relative to gatorade in isolation, with the ratio being maintained.[615]

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]
Recommended Dose: 3-6 grams before or during exercise. A ratio of two parts leucine to one part each of isoleucine and valine appears to be most beneficial. As Krissy Kendall, PhD, explains in "The Top 7 Supplements to Boost Endurance Performance," BCAAs can be just as effective for endurance athletes like runners, rowers, and cyclists as they can be for lifters and bodybuilders.
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]
In today's extra-large society, we tend to focus on the admirable guys who train hard and switch up their diet to transform their bodies by losing weight. We highlight their quests to lead healthier lives every chance we get — but there's another side of the wellness scale that can be just as difficult, depending on your body's makeup: Gaining mass and muscle.
MuscleTech Cell-Tech is the best creatine stack. A lot of products claim to be more effective than regular monohydrate and while that’s seldom true, Cell-Tech has the goods. It combines creatine with a big 38 grams of carbohydrates and some alpha-lipolic acid, and some studies actually show that this trifecta could be more effective at sending creatine to the muscles than plain creatine.
HMB supplementation is claimed to build muscle size and strength and promote fat loss in conjunction with a strength program. Studies of HMB have shown some benefit to strength athletes in building muscle bulk but the benefits are relatively small and the cost of HMB is high. The effective dose seems to be 3 grams/day divided into 1 gram three times a day. Probably not worth taking. Beta-alanine is the new guy on the block and has not been evaluated sufficiently in my view. It may provide some advantage in high-intensity sports like weight training but it’s much too early to know that it does. Some early studies are flawed. Save your money or try creatine instead.
Of the three, protein will of course play the most important role in the muscle building process (like calories, it’s one our required “supplies”), although fat and carbs will still be important for other reasons which range from optimizing hormone production (e.g. testosterone, the muscle building hormone) to enhancing training performance and recovery.
Some protein powders are loaded with junk. We recommend this grass-fed protein isolate because it is a non-GMO product and contains no artificial sweeteners. It is a US-based product, and the whey protein is cultivated from American cows. With 28 grams of protein in one scoop, one spoonful of this powder may provide the equivalent protein profile of a whole meal. What’s even better is that one scoop is only 120 calories. This powder gives you quite a bit of protein for minimal calories, keeping you lean.

^ Haykowsky MJ, Liang Y, Pechter D, Jones LW, McAlister FA, Clark AM (June 2007). "A meta-analysis of the effect of exercise training on left ventricular remodeling in heart failure patients: the benefit depends on the type of training performed". Journal of the American College of Cardiology. 49 (24): 2329–36. doi:10.1016/j.jacc.2007.02.055. PMID 17572248.
Most typical bodybuilding programs have way too many sets and reps and use the wrong exercises. However, if you lower the total volume, go heavier, and use compound movements as I’ve outlined above, there is nothing wrong with a body-part split for advanced lifters. In fact, it’s often less stressful to the joints than your average upper/lower split.
Tough workouts drive muscle growth, but they generally cause a lot of damage to your muscles to do so. This damage often results in soreness for several days, which can make it tough to get to the gym or sometimes even move. Many bodybuilding supplements contain ingredients that work to reduce the breakdown of muscle during workouts, making the recovery process easier on the body.
Creatine supplementation has once been noted to improve wellbeing and fatigue resistance in people with DM2, but has twice failed for people with DM1. In all three studies, it has failed to improve power output. This is thought to be due to a reduction in the expression of the creatine transporter preventing an increase in muscular phosphocreatine content.

Plyometrics exploit the stretch-shortening cycle of muscles to enhance the myotatic (stretch) reflex. This involves rapid alternation of lengthening and shortening of muscle fibers against resistance. The resistance involved is often a weighted object such as a medicine ball or sandbag, but can also be the body itself as in jumping exercises or the body with a weight vest that allows movement with resistance. Plyometrics is used to develop explosive speed, and focuses on maximal power instead of maximal strength by compressing the force of muscular contraction into as short a period as possible, and may be used to improve the effectiveness of a boxer's punch, or to increase the vertical jumping ability of a basketball player. Care must be taken when performing plyometric exercises because they inflict greater stress upon the involved joints and tendons than other forms of exercise.

The majority of studies focusing on creatine supplementation report an increase in the body’s’ creatine pool [15-17]. There is a positive relationship between muscle creatine uptake and exercise performance [17]. Volek et al [18] observed a significant increase in strength performance after 12 weeks creatine supplementation with a concurrent periodized heavy resistance training protocol. The creatine supplementation protocol consisted of a weeklong loading period of 25 g/d followed by a 5 g maintenance dose for the remainder of the training. These positive effects were attributed to an increased total creatine pool resulting in more rapid adenosine triphosphate (ATP) regeneration between resistance training sets allowing athletes to maintain a higher training intensity and improve the quality of the workouts along the entire training period.
Creatine is a powerful supplement for strength and muscle gain. It always recommended utilize creatine before the workout. It gives you the strength and power of more repetition. With creatine, you can also use SR-9009. SR-9009 has the capabilities of lowering obesity and reversing metabolic syndrome. SR-9009 allows to perform more cardio training, weight loss, improve cholesterol levels, and gain lean muscle mass. Hope this information will help someone.
Back in the 1970s, scientists discovered that taking creatine in supplement form might enhance physical performance. In the 1990s, athletes started to catch on, and creatine became a popular sports supplement. The supplement is particularly popular among high school, college, and professional athletes, especially football and hockey players, wrestlers, and gymnasts. 
AAKG β-hydroxy β-methylbutyrate Carnitine Chondroitin sulfate Cod liver oil Copper gluconate Creatine/Creatine supplements Dietary fiber Echinacea Elemental calcium Ephedra Fish oil Folic acid Ginseng Glucosamine Glutamine Grape seed extract Guarana Iron supplements Japanese Honeysuckle Krill oil Lingzhi Linseed oil Lipoic acid Milk thistle Melatonin Red yeast rice Royal jelly Saw palmetto Spirulina St John's wort Taurine Wheatgrass Wolfberry Yohimbine Zinc gluconate
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.
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.
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.
Mr. Olympia is part of the International Federation of Bodybuilding Professional League. The I.F.B.B. says that it operates under the guidelines of the World Anti-Doping Agency and that competitors are subject to drug testing. Chang, who oversees the Mr. Olympia contest, said that I.F.B.B. testing is random, but is not conducted during the Mr. Olympia contest itself.
To succeed and thrive as a bodybuilder, it takes more than overwhelming muscular strength or athletic prowess. Judges select bodybuilding champions based on muscle mass, definition, proportion, symmetry, and an athlete’s stage presence. Given the criteria, it is no surprise that most serious bodybuilders consider supplementation to be an essential component of their training regimen.
The first thing you need is a weight training program that signals the muscle building process to begin. Research has shown that a well designed program will generate this “signal” via a combination of progressive tension overload (as in, getting stronger over time), metabolic stress (as in, fatiguing the muscle and getting “the pump”), and muscular damage (as in, actual damage to the muscle tissue itself).
The body's pool of creatine can be replenished either from food (or supplements) or through synthesis from precursor amino acids. Dietary sources include beef, tuna, cod, salmon, herring, and pork [2]. The normal dietary intake of creatine is 1-2 g/day, although vegetarians may consume less [3,4]. Dietary creatine is absorbed from the intestines into the bloodstream. If the dietary supply is limited, creatine can be synthesized from the body stores of the amino acids glycine, arginine, and methionine. The kidneys use glycine and arginine to make guanidinoacetate, which the liver methylates to form creatine [1], which is transported to the muscle cells for storage. It is also stored in the kidneys, sperm cells, and brain tissue [5].
Mr. Olympia is part of the International Federation of Bodybuilding Professional League. The I.F.B.B. says that it operates under the guidelines of the World Anti-Doping Agency and that competitors are subject to drug testing. Chang, who oversees the Mr. Olympia contest, said that I.F.B.B. testing is random, but is not conducted during the Mr. Olympia contest itself.
According to BodyBuilding.com, adenosine triphosphate (ATP) is made up of a nucleotide bonded to three phosphate groups. When one of those phosphate groups is cleaved from the ATP molecule, a lot of energy is made available. That energy is used to fuel chemical reactions in cells, and ATP becomes adenosine diphosphate (ADP). Creatine enables the release of energy from stored ATP and is converted to creatinine. 

There are several ways to enhance the quality of a workout, and some changes can even be made during each rep. “Constant tension should be applied to the last five reps of every working set, meaning, do the first 5-6 reps normal tempo, and the last few reps should be held for at least two seconds at the peak of the contraction,” says Heath. “This allows your muscles to have more time under tension and you work different muscle fibers.” Hold the weight at the top for a maximum pump.

The harder an exercise is – both in terms of technicality and physical/mental demand – the more rest there should usually be. So exercises like squats and deadlifts should have more rest between sets than exercises like leg extensions and leg curls. And exercises like various bench presses, shoulder presses, rows and pull-ups should have more rest between sets than bicep curls, tricep extensions, chest flies and lateral raises.

Of course, cardio is an important part of fitness too, but the benefits of strength training are major. Strength training helps build muscle, and lean muscle is better at burning calories when the body is at rest, which is important whether you're trying to lose weight or maintain it. It also helps strengthens joints and bones, avoid injury, improve your muscular endurance, and will help you give it your all during your other workouts, whether that means setting a new PR if you're a runner or pushing (and pulling) a little harder with your legs during your favorite indoor cycling class.
Studies have deemed staying in the range of 3 to 5 g per day range for maintenance to be safe, and while higher levels have been tested under acute conditions without adverse effects, there isn’t sufficient evidence to determine long-term safety. (8) If you’re interested in upping your creatine consumption, you should work with your doctor or dietitian to make sure it's right for your goals and health history.
Creatine is used and researched in a clinical setting to investigate various pathologies or disorders such as myopathies [3,4] and is also used as an ergogenic aid for improving health and sports performance in athletes [5]. As an oral supplement, the most widely used and researched form is creatine monohydrate (CM). When orally ingested, CM has shown to improve exercise performance and increase fat free mass [5-9].
Focus on form. Good form means you can reap all of the benefits of your workout and avoid injuries at the same time. To maintain proper form, pay attention to your posture (stand tall with chest lifted and abs held tight), move slowly (this ensures you're relying on muscles, not momentum, to do the lifting), and remember to breathe. Many people hold their breath while exerting, but exhaling during the hardest part of the exercise helps fuel the movement.

Heath bent his legs — each thigh about 32 inches around, bigger than his waist — and lifted the black case. Inside was his latest Mr. Olympia trophy. In bodybuilding, it is called the Sandow, and Heath has won the last six, most recently in Las Vegas in September. Arnold Schwarzenegger, still the world’s most famous bodybuilder, won six in a row, too, and then a seventh a few years later. Two men, Lee Haney and Ronnie Coleman, have won eight.

In vitro, creatine (0.125mM or higher) can reduce excitotoxicity from glutamate, which is thought to be secondary to preserving intracellular creatine phosphate levels.[209] Glutamate-induced excitotoxicity is caused by excessive intracellular calcium levels resulting from ATP depletion. Since high levels of calcium inside the cell are toxic, ATP preserves membrane integrity,[210] in part by promoting calcium homeostasis. When ATP is depleted, the sodium-potassium ATPase pump (Na+,K+-ATPase) stops working, leading to sodium accumulation in the cell. This reduces the activity of the sodium-calcium exchange pump, which, alongside a lack of ATP, reduces calcium efflux through the Na+,K+-ATPase. Thus, ATP depletion leads to intracellular calcium overload, loss of membrane potential, and excitotoxic cell death. Therefore, by helping preserve ATP levels, creatine is protective against excitotoxicity. This protective effect was noted after either creatine preloading or addition up to 2 hours after excitotoxicity.[209] Protection from glutamate-induced toxicity also extends to glial cells[211] and is additive with COX2 inhibition.[212]
In summary, creatine salts have been show to be less stable than CM. However the addition of carbohydrates could increase their stability [62]. The potential advantages of creatine salts over CM include enhanced aqueous solubility and bioavailability which would reduce their possible gastrointestinal adverse effects [63]. The possibility for new additional formulation such as tablets or capsules is interesting for its therapeutic application due to its attributed better dissolution kinetics and oral absorption compared to CM [63]. However more complete in vivo pharmaceutical analysis of creatine salts are required to fully elucidate their potential advantages/disadvantages over the currently available supplement formulations.

Exercise is highly effective in increasing your lean body mass, which is essentially muscle. In a study published in 2012, progressive resistance training helped men ages 50 to 83 gain an average of 2.4 pounds of lean body mass over an average of 20.5 weeks. Progressive resistance training involves performing weight bearing exercises. In addition, you must slowly increase the challenge of the exercise over time by increasing the weight, reps and/or sets. Studies show that either increasing reps or weight amount will work. So, if you don’t want to lift more weight, you can just do more reps and still build muscle. 

The motor proteins actin and myosin generate the forces exerted by contracting muscles. Current recommendations suggest that bodybuilders should consume 25–30% of protein per total calorie intake to further their goal of maintaining and improving their body composition.[30] This is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight per day is ideal, some suggesting that less is sufficient, while others recommending 1.5, 2, or more.[31] It is believed that protein needs to be consumed frequently throughout the day, especially during/after a workout, and before sleep.[32] There is also some debate concerning the best type of protein to take. Chicken, turkey, beef, pork, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans, and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in many popular brands of protein supplements and is preferred by many bodybuilders because of its high Biological Value (BV) and quick absorption rates. Whey protein also has a bigger effect than casein on insulin levels, triggering about double the amount of insulin release.[33] That effect is somewhat overcome by combining casein and whey. Bodybuilders are usually thought to require protein with a higher BV than that of soy, which is additionally avoided due to its claimed estrogenic properties. Still, some nutrition experts believe that soy, flax seeds and many other plants that contain the weak estrogen-like compounds or phytoestrogens, can be used beneficially, as phytoestrogens compete with estrogens for receptor sites in the male body and can block its actions. This can also include some inhibition of pituitary functions while stimulating the P450 system (the system that eliminates hormones, drugs and metabolic waste product from the body) in the liver to more actively process and excrete excess estrogen.[34][35] Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.[36]

Creatine is thought to improve strength, increase lean muscle mass, and help the muscles recover more quickly during exercise. This muscular boost may help athletes achieve bursts of speed and energy, especially during short bouts of high-intensity activities such as weight lifting or sprinting. However, scientific research on creatine has been mixed. Although some studies have found that it does help improve performance during short periods of athletic activity, there is no evidence that creatine helps with endurance sports. Research also shows that not everyone's muscles respond to creatine; some people who use it see no benefit.
Lyoo, I. K., Yoon, S., Kim, T. S., Hwang, J., Kim, J. E., Won, W., Bae, S., & Renshaw, P. F. (2012, September). A randomized, double-blind placebo-controlled trial of oral creatine monohydrate augmentation for enhanced response to a selective serotonin reuptake inhibitor in women with major depressive disorder. American Journal of Psychiatry. 169(9):937-45. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/22864465
Synthesis primarily takes place in the kidney and liver, with creatine then being transported to the muscles via the blood. The majority of the human body's total creatine and phosphocreatine stores is located in skeletal muscle, while the remainder is distributed in the blood, brain, and other tissues.[17][18][20] Typically, creatine is produced endogenously at an estimated rate of about 8.3 mmol or 1 gram per day in young adults.[16][17] Creatine is also obtained through the diet at a rate of about 1 gram per day from an omnivorous diet.[17][18] Some small studies suggest that total muscle creatine is significantly lower in vegetarians than non-vegetarians, as expected since foods of animal origin are the primary source of creatine. However, subjects happened to show the same levels after using supplements.[21]