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.
Replacement therapy may produce desired results, such as greater muscle mass and a stronger sex drive. However, the treatment does carry some side effects. Oily skin and fluid retention are common. The testicles may also shrink, and sperm production could decrease significantly. Some studies have found no greater risk of prostate cancer with testosterone replacement therapy, but it continues to be a topic of ongoing research.
Creatine transport has been shown to increase when muscle creatine stores are depleted. This was only noted to occur in muscle with particular fiber types (soleus and red gastrocnemius), while other fiber types, such as white grastrocnemius, did not show any clear trend.[146] This indicates that transport in relation to total creatine levels varies across different muscle fiber types.
^ "Popular sports supplements contain meth-like compound". USA Today. October 25, 2013. Cohen said researchers informed the FDA in May about finding the new chemical compound in Craze. The team found the compound — N,alpha-diethylphenylethylamine — has a structure similar to methamphetamine, a powerful, highly addictive, illegal stimulant drug. They believe the new compound is likely less potent than methamphetamine but greater than ephedrine.
It is hard to know how many men among us have TD, although data suggest that overall about 2.1% (about 2 men in every 100) may have TD. As few as 1% of younger men may have TD, while as many as 50% of men over 80 years old may have TD. People who study the condition often use different cut-off points for the numbers, so you may hear different numbers being stated.
If you'’re looking to add muscle mass to your frame, hitting the weights hard is a given. Quality time in the gym begins a cascade of changes that will stimulate your muscles to grow bigger in response to the challenges you throw their way. It'’s tempting to think that'’s all it takes to add muscle to your body. After all, you can actually feel your biceps growing after an intense set of curls.
So, for example, with the moves above you'd do 15 squats followed by 15 push-ups. Take a little breather then repeat that two more times. Then you move on to your walking lunges and lat pull-downs (and repeat those three times total, too). You can really do anywhere from eight reps to 15 (and even just two sets, if you don't have time for three), but "it’s not a bad idea for beginners to start with a 15-rep range to get comfortable with the exercises," says Davis. And while there's some debate over whether three sets of an exercise is really best, "it’s a great beginner model," says Davis. Don't overcomplicate things when you're just getting started.
Because I don’t want you to have to waste all the years and money that I did (not to mention the surgeon’s bills), I came up with a method of training and eating specifically for skinny-fat, injury-prone hard-gainers: guys who historically can’t gain muscle doing the workouts they find in magazines or on blogs. It’s also perfect for all guys over age 35 who need to be smarter with their training as they age.

Sculthorpe et al (2010) has shown that a 5 day (25g/d) loading protocol of creatine supplementation followed by a further 3 days of 5 g/d negatively influence both active ankle dorsiflexion and shoulder abduction and extension range of movement (ROM) in young men. There are two possible theories to explain these effects: 1) Creatine supplementation increases intracellular water content resulting in increased muscle stiffness and resistance to stretch; 2) Neural outflow from the muscle spindles is affected due to an increased volume of the muscle cell. The authors highlight that the active ROM measures were taken immediately after the loading phase and the reduced active ROM may not be seen after several weeks of maintenance phase [45]. Hile et al [46] observed an increase in compartment pressure in the anterior compartment of the lower leg, which may also have been responsible for a reduced active ROM.
Creatine is a natural source of energy for muscle contraction. The body produces creatine in the liver, kidneys, and pancreas. People can also get creatine by eating meat or fish. (Vegetarians may have lower amounts of creatine in their bodies.) Most of the creatine in the body is stored in skeletal muscle and used during physical activity. The rest is used in the heart, brain, and other tissues.
In the last week leading up to a contest, bodybuilders usually decrease their consumption of water, sodium, and carbohydrates, the former two to alter how water is retained by the body and the latter to reduce glycogen in the muscle. The day before the show, water is removed from the diet, and diuretics may be introduced, while carbohydrate loading is undertaken to increase the size of the muscles through replenishment of their glycogen. The goal is to maximize leanness and increase the visibility of veins, or "vascularity". The muscular definition and vascularity are further enhanced immediately before appearing on stage by darkening the skin through tanning products and applying oils to the skin to increase shine. Some competitors will eat sugar-rich foods to increase the visibility of their veins. A final step, called "pumping", consists in performing exercises with light weights or other kinds of low resistance (for instance two athletes can "pump" each other by holding a towel and pulling in turn), just before the contest, to fill the muscles with blood and further increase their size and density.
Furthermore, because creatine can help restore ATP levels, increasing energy, it can lead to reduced amounts of heart muscle stress. More energy in your life will result in less pain, stress, and boost morale in everyday life which has a significant role in improving heart health. The increased capacity to exercise is also crucial in maintaining and improving heart health.
Increasing creatine levels in skeletal muscle to 687% of baseline (0.5mM creatine, thought to be equivalent to 5g creatine[135]) doesn’t seem to per se increase glucose uptake, but increases glucose oxidation (140% of baseline)[341] which is due to a two-fold increase in the activity of α1 and α2 subunits of AMPK, a potency comparable to 1mM of the reference drug AICAR.[341] Glucose uptake associated with AMPK has indeed been noted in diabetic people who are undergoing physical exercise[342] and in contracting skeletal muscle cells,[153][330] but according to rat[343][344][345] and in vitro studies of cells not being contracted,[341] this is not a per se effect of non-exercising tissue but an augmentation of exercise-induced glucose uptake.
There's good news, though: These temporary muscle pumps are critical to improving muscle hypertrophy, or muscle growth, according to 2014 research in the Strength and Conditioning Journal. So you can think of your weight-room pump as a preview of the muscle results that are to come. Speaking of which, here's an expert-endorsed timeline to reach your muscle-building goals.
The sexual hormone can encourage fair behavior. For the study, subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. Two later studies have empirically confirmed these results.[75][76][77] However men with high testosterone were significantly 27% less generous in an ultimatum game.[78] The Annual NY Academy of Sciences has also found anabolic steroid use which increase testosterone to be higher in teenagers, and this was associated with increased violence.[79] Studies have also found administered testosterone to increase verbal aggression and anger in some participants.[80]

In the stomach, creatine can degrade by about 13% due to the digestive hormone pepsin, as assessed by simulated digestion.[127] Although creatinine is a known byproduct of creatine degradation, simulated gastric digestion did not increase creatinine levels, indicating that other breakdown products were formed. However, creatinine was noted to increase in the presence of pancreatin, a mixture of pancreatic enzymes.[127]  

During the second trimester, androgen level is associated with sex formation.[13] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. A mother's testosterone level during pregnancy is correlated with her daughter's sex-typical behavior as an adult, and the correlation is even stronger than with the daughter's own adult testosterone level.[14]
Creatine has demonstrated neuromuscular performance enhancing properties on short duration, predominantly anaerobic, intermittent exercises. Bazzucch et al [27] observed enhanced neuromuscular function of the elbow flexors in both electrically induced and voluntary contractions but not on endurance performance after 4 loading doses of 5 g creatine plus 15 g maltodextrin for 5/d in young, moderately trained men. Creatine supplementation may facilitate the reuptake of Ca2+ into the sacroplasmic reticulum by the action of the Ca2+ adenosine triphosphatase pump, which could enable force to be produced more rapidly through the faster detachment of the actomyosin bridges.
Mitochondrial myopathies are a subgroup of mitochondrial cytopathies in which the skeletal muscle is negatively influenced. They are characterized by weaknesses in muscular function and energy metabolism.[547] These particular myopathies are thought to benefit from creatine supplementation, since creatine can help with some of the dysregulated energy production.[548]
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.

In regard to the loading period, two reviews suggest that the range of weight gain associated with creatine supplementation at 20g for 7 days is in the range of 0.9-1.8kg (1.98-3.96lbs).[612][613] The highest reported increase in water weight associated with creatine loading, although measured a month after loading started (after a maintenance phase) was 3.8kg (8.36lbs).[614]
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

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.
Creatine transport has been shown to increase when muscle creatine stores are depleted. This was only noted to occur in muscle with particular fiber types (soleus and red gastrocnemius), while other fiber types, such as white grastrocnemius, did not show any clear trend.[146] This indicates that transport in relation to total creatine levels varies across different muscle fiber types.

AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.

The incidence of liver damage from herbal and dietary supplements is about 16–20% of all supplement products causing injury, with the occurrence growing globally over the early 21st century.[2] The most common liver injuries from weight loss and bodybuilding supplements involve hepatocellular damage with resulting jaundice, and the most common supplement ingredients attributed to these injuries are catechins from green tea, anabolic steroids, and the herbal extract, aegeline.[2]
One of the biggest goals of bodybuilders is to increase their muscle size and strength. Bodybuilding supplements often contain many ingredients that help to encourage this. Branched-chain amino acids are a common ingredient that can significantly increase muscle growth. Other ingredients help to increase the levels of hormones, such as growth hormone and testosterone, that can also stimulate muscle growth.
In the last few years, a lot of men and women have switched over to a pellet that goes under your skin. This is probably the best way to take testosterone now. The pellet is life-changing for both men and women (the dose for women is much lower than it is for men). Women, you won’t get bulky and grow a beard when you take testosterone to achieve normal levels, but you will probably lean out a little without losing your curves, and your energy and sex drive will be amazing. Female bodybuilders who experience weird scary side effects are taking anabolic steroids.
The first published results (not blinded) noted that a loading phase of 20g of creatine for a week, followed by 3g daily for up to six months, was able to enhance maximal voluntary isometric muscular contraction (MVIC) on a dynamometer for both the knee and elbow joints, with enhanced fatigue resistance on the same joints in more than half of subjects (53-70% response rate).[545] 

In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40] This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.
Lie on your back on the floor and bend one knee so that your foot is flat on the floor. Keeping your opposite leg straight, push your foot into the floor, raising your hips until both thighs are in line with each other. Reverse the motion to return to the starting position. That’s one rep. Complete all your reps on one leg, and then switch legs and repeat.

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. 

The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group[191] was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",[192] and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and well-being.[193]
No need to worry! This myth that caffeine counteracts creatine came from the simple, but wrong logic that because caffeine accelerates the nervous system and uses more water, it would counteract creatine because creatine helps your body retain water. While both of these statements are true, it does not mean they “cancel” eachother out, all that it means is that your body will be able to stay hydrated longer if you are taking creatine and caffeine opposed to just taking caffeine.
Ballistic training incorporates weight training in such a way that the acceleration phase of the movement is maximized and the deceleration phase minimized; thereby increasing the power of the movement overall. For example, throwing a weight or jumping whilst holding a weight. This can be contrasted with a standard weight lifting exercise where there is a distinct deceleration phase at the end of the repetition which stops the weight from moving.[40]
Practice Sleep Hygiene – For optimal health of your mind and body, it is recommended that adults get 7 to 8 hours of sleep every day. Lower or more amounts of sleep can exacerbate your depressive symptoms. Sleep hygiene practices include limiting daytime naps, scheduling a regular sleep and wake-up times, and ensuring the environment is rid of potential sleep disruptors such as light, noise, and heat.

There have been a few reported renal health disorders associated with creatine supplementation [73,74]. These are isolated reports in which recommended dosages are not followed or there is a history of previous health complaints, such as renal disease or those taking nephrotoxic medication aggravated by creatine supplementation [73]. Specific studies into creatine supplementation, renal function and/or safety conclude that although creatine does slightly raise creatinine levels there is no progressive effect to cause negative consequences to renal function and health in already healthy individuals when proper dosage recommendations are followed [73-77]. Urinary methylamine and formaldehyde have been shown to increase due to creatine supplementation of 20 g/d; this however did not bring the production outside of normal healthy range and did not impact on kidney function [56,78]. It has been advised that further research be carried out into the effects of creatine supplementation and health in the elderly and adolescent [73,75]. More recently, a randomized, double blind, 6 month resistance exercise and supplementation intervention [79] was performed on elderly men and women (age >65 years) in which subjects were assigned to either a supplement or placebo group. The supplement group was given 5 g CM, 2 g dextrose and 6 g conjugated linoleic acid/d, whilst the placebo group consumed 7 g dextrose and 6 g safflower oil/d. CM administration showed significantly greater effects to improve muscular endurance, isokinetic knee extension strength, fat free mass and to reduce fat mass compared to placebo. Furthermore the supplement group had an increase in serum creatinine but not creatinine clearance suggesting no negative effect on renal function.
Start with hand weights in your hands just outside your thighs, or a barbell on the ground. Keep your feet hip distance apart and your tailbone/hips slightly tucked. Lower the upper body while keeping the chest upright and butt sticking back. Keep your back flat (try not to hunch or round). Drive your back upright and your hips forward so you end up standing up straight, drawing the weights in your hands until they are about the height of your mid-shin or just below the knees. Lower back down as you started and repeat.

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]
We’ll define the “bigger muscle groups” as being chest, back, quads and hamstrings, and the “smaller muscle groups” as being biceps, triceps and maybe abs. Shoulders are really somewhere in the middle, though I tend to lean more toward the “smaller” guidelines. Calves, while technically small, are another muscle group that is somewhere in the middle, and I can really go either way depending on the needs of the person.
Kerksick, C. M., Wilborn, C. D., Campbell, W. I., Harvey, T. M., Marcello, B. M., Roberts, M. D., Parker, A. G., Byars, A. G., Greenwood, L. D., Almada, A. L., Kreider, R. B., and Greenwood, M. The effects of creatine monohydrate supplementation with and without D-pinitol on resistance training adaptations. J.Strength.Cond.Res. 2009;23(9):2673-2682. View abstract.
The rise in testosterone levels during competition predicted aggression in males but not in females.[90] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[91] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[92] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[93] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[94] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[95]
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