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. 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. This does not rule out a possible systemic exercise-driven increase in creatine uptake, and the increase in creatine noted above 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.
Two of the immediate metabolites of testosterone, 5α-DHT and estradiol, are biologically important and can be formed both in the liver and in extrahepatic tissues. Approximately 5 to 7% of testosterone is converted by 5α-reductase into 5α-DHT, with circulating levels of 5α-DHT about 10% of those of testosterone, and approximately 0.3% of testosterone is converted into estradiol by aromatase. 5α-Reductase is highly expressed in the male reproductive organs (including the prostate gland, seminal vesicles, and epididymides), skin, hair follicles, and brain and aromatase is highly expressed in adipose tissue, bone, and the brain. As much as 90% of testosterone is converted into 5α-DHT in so-called androgenic tissues with high 5α-reductase expression, and due to the several-fold greater potency of 5α-DHT as an AR agonist relative to testosterone, it has been estimated that the effects of testosterone are potentiated 2- to 3-fold in such tissues.
As you grow older, an active life is more important than ever. Even as the world tells you it's time to retire, relax, and take it easy, your body is craving for you to keep moving. And though you may be ready to retire from your 9-5, don’t hang up your walking shoes quite yet. The truth is that if you really want to enjoy these golden years and get more quality time from them, your best strategy is to exercise regularly.
Like other steroid hormones, testosterone is derived from cholesterol (see figure). The first step in the biosynthesis involves the oxidative cleavage of the side-chain of cholesterol by cholesterol side-chain cleavage enzyme (P450scc, CYP11A1), a mitochondrial cytochrome P450 oxidase with the loss of six carbon atoms to give pregnenolone. In the next step, two additional carbon atoms are removed by the CYP17A1 (17α-hydroxylase/17,20-lyase) enzyme in the endoplasmic reticulum to yield a variety of C19 steroids. In addition, the 3β-hydroxyl group is oxidized by 3β-hydroxysteroid dehydrogenase to produce androstenedione. In the final and rate limiting step, the C17 keto group androstenedione is reduced by 17β-hydroxysteroid dehydrogenase to yield testosterone.
Arginine mainly benefits the body in two ways. The first of these is by producing nitric oxide. When arginine enters the body, some of it gets converted into nitric oxide. Nitric oxide is important for regulating blood pressure, as it can enlarge the blood vessels. Larger blood vessels allow the body to increase blood flow throughout the body, bringing extra nutrients and oxygen to the muscles during exercise.
Low testosterone levels can cause mood disturbances, increased body fat, loss of muscle tone, inadequate erections and poor sexual performance, osteoporosis, difficulty with concentration, memory loss and sleep difficulties. Current research suggests that this effect occurs in only a minority (about 2%) of ageing men. However, there is a lot of research currently in progress to find out more about the effects of testosterone in older men and also whether the use of testosterone replacement therapy would have any benefits.
Consuming sufficient high-quality protein is essential for building muscle. Current recommendations are to consume a minimum of 0.8g of protein for each kg of body weight, however, this is really only applicable to the average sedentary individual. Current evidence shows that to support muscle development, protein intake is the key, therefore the recommended 0.8g per kg should be increased to 1.5-2.0g of protein per kg of body weight. For an 80 kg individual, that would equate to 120-160 grams of protein per day.
Exercise is the original testosterone booster, and it’s one of the most powerful full-body hacks around. Men see a sharp increase in both testosterone and human growth hormone (HGH) after lifting weights, and the boost is greater with shorter rest time between sets (1 minute rest outperforms 3 minutes rest) . With the shorter rest time, women also get a large boost in HGH.
SAMe is the primary methyl donor in the human body, and supplements that preserve SAMe (such as trimethylglycine; TMG) promote a variety of benefits in the human body, like a reduction in homocysteine and reduced risk of fatty liver. Creatine has been implicated in both reducing homocysteine and preventing fatty liver in rodents, thought to be secondary to preserving SAMe.
Jager et al  observed 1.17 and 1.29 greater peak plasma creatine concentration 1 hour after ingesting creatine pyruvate compared to isomolar amount of CM and creatine citrate respectively. However time to peak concentration, and velocity constants of absorption and elimination, was the same for all three forms of creatine. Although not measured in this study it is questionable that these small differences in plasma creatine concentrations would have any effect on the increase of muscle creatine uptake. Jäger et al  investigated the effects of 28-days of creatine pyruvate and citrate supplementation on endurance capacity and power measured during an intermittent handgrip (15 s effort per 45s rest) exercise in healthy young athletes. The authors used a daily dose protocol with the intention to slowly saturate muscle creatine stores. Both forms of creatine showed slightly different effects on plasma creatine absorption and kinetics. The two creatine salts significantly increased mean power but only pyruvate forms showed significant effects for increasing force and attenuating fatigability during all intervals. These effects can be attributed to an enhanced contraction and relaxation velocity as well as a higher blood flow and muscle oxygen uptake. On the other hand, the power performance measured with the citrate forms decreases with time and improvements were not significant during the later intervals. In spite of these positive trends further research is required about the effects of these forms of creatine as there is little or no evidence for their safety and efficacy. Furthermore the regularity status of the novel forms of creatine vary from country to country and are often found to be unclear when compared to that of CM .
Natural remedies for treating erectile dysfunction Erectile dysfunction has many causes, can affect any male, and is often distressing? Some people advocate several different natural remedies, mostly herbs and other plants. Here, we look at their merits and side effects, plus lifestyle changes, and alternative therapies that may bring relief for erectile dysfunction. Read now
The rise in testosterone levels during competition predicted aggression in males but not in females. Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression. 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. 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. Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli. Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.