Creatine is known to be present in the retina due to the expression of creatine kinase (CK)[466][39] and the GAMT enzyme of creatine synthesis, which is also present in the mammalian retina.[467] Creatine in the blood can be transported into the retina via the creatine transporter (confirmed in humans[468]), and inhibiting transporter activity (by depleting the medium of chloride and sodium) reduces uptake by 80%.[469] The fact that not all uptake was inhibited suggests that another transporter, such as the monocarboxylate transporter MCT12 (or SLC16A12),[470] plays a role, perhaps moreso in the lens, where its levels were comparable to that of the major creatine transporter SLC6A8.[470] 
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.
While muscle growth is critical for bodybuilding, getting rid of extra fat is a necessity to improve your total physique. These supplements can help to increase your metabolism, forcing your body to burn away more of its fat stores. They can also slow down the digestion process to prevent excess fat and carbohydrates from entering the body and being stored.

In well-trained endurance runners, creatine (with glycerol for hyperhydration) caused a relatively large increase in body weight gain (0.90+/-0.40kg) and water weight (0.71+/-0.42L) but failed to negatively influence performance over 30 minutes in the heat.[3] This failure to improve physical performance in the heat with creatine loading (despite water retention) has been noted elsewhere.[346] 

The winner of the annual IFBB Mr. Olympia contest is generally recognized as the world's top male professional bodybuilder. The winner of the Women's Physique portion of the competition is widely regarded as the world's top female professional bodybuilder. The title is currently held by Juliana Malacarne, who has won every year since 2014. Since 1950, the NABBA Universe Championships have been considered the top amateur bodybuilding contests, with notable winners such as Reg Park, Lee Priest, Steve Reeves, and Arnold Schwarzenegger. Winners generally go on to become professional athletes.

Many non-competitive bodybuilders choose not to adopt this conventional strategy, as it often results in significant unwanted fat gain during the "bulking" phase. The attempt to increase muscle mass in one's body without any gain in fat is called clean bulking. Competitive bodybuilders focus their efforts to achieve a peak appearance during a brief "competition season".[citation needed] Clean bulking takes longer and is a more refined approach to achieving the body fat and muscle mass percentage a person is looking for. A common tactic for keeping fat low and muscle mass high would be to have higher calorie and lower calorie days to maintain a balance between gain and loss. Many clean bulk diets start off with a moderate amount of carbs, moderate amount of protein, and a decently low amount of fats. "Gaining lean muscle means going for leaner cuts of meat, like flank steaks and fillets, chicken, and, of course, fish," says White[who?]. "Enjoy your meat with some starch: rice, beans, quinoa, whole-grain couscous, or sweet potato, for example".[20] To maintain a clean bulk it is important to reach calorie goals every day. Macronutrient goals will be different for each person, but, it is ideal to get as close as possible.
Those micro-tears that are such a key factor for muscle-building need rest to rebuild themselves and grow stronger. When do they do that? When you’re asleep! “You have to rest and feed your muscles between workouts or you will tear them down and they will become weaker,” says Olson. “Over time, you run the risk of over-training, which can result in injury, and possibly even more sleep troubles.”
As you've probably heard from any muscle-bound behemoth you've ever encountered, protein is the key to building muscle. Just because the shake-pounding meathead has become a trope, however, doesn't mean they're wrong; protein really is the fuel your muscles need to grow. That's real capital-S Science, not just bro-science manufactured by supplements companies.
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.

Now, creatine combines with inorganic phosphate to form phosphocreatine in a reaction accelerated by an enzyme named creatine kinase. Most of us increase our phosphocreatine stores when we consume creatine. In turn, our fortified phosphocreatine stores can donate additional high-energy phosphate groups during very energy-demanding activities, more efficiently recycling ATP from ADP. This is the main way creatine supplementation improves high-intensity exercise performance.

Liquid creatine has been shown to be less effective than creatine monohydrate.[69] This reduced effect is due to the passive breakdown of creatine over a period of days into creatinine, which occurs when it is suspended in solution.[70] This breakdown is not an issue for at-home use when creatine is added to shakes, but it is a concern from a manufacturing perspective in regard to shelf-life before use.


Men who produce more testosterone are more likely to engage in extramarital sex.[55] Testosterone levels do not rely on physical presence of a partner; testosterone levels of men engaging in same-city and long-distance relationships are similar.[54] Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women.[59] 
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