Spero Karas, MD, assistant professor of orthopaedics in the division of sports medicine at Emory University, says that testosterone, the male hormone responsible for muscle growth, maxes out between the ages of 16 and 18. It reaches a plateau during the 20s and then begins to decline. As a result, muscle building after the adolescent years can be challenging, he says.
If you’re looking to put on extra muscle mass and build strength, there are a few things that need to occur. The first of these, even though it may seem obvious, is that you will need to have an exercise routine. To stimulate maximum muscle growth, you’ll need to challenge yourself in the gym, forcing your muscles to adapt to heavier workloads by increasing in size and strength.
Due to this relative deficiency-state in vegetarians and vegans, some aspects of creatine supplementation are seen as more akin to normalizing a deficiency, rather than providing the benefits of supplementation. In young vegetarians, but not omnivores, creatine supplementation can enhance cognition.[60][61] The increased gain in lean mass may be more significant in vegetarians, relative to omnivores.[59] Supplementation of creatine in vegetarians appears to normalize the gap in storage between vegetarians and omnivores.[62] This is possibly related to a correlation seen in survey research, where vegetarianism and veganism appear to be more commonly affected by some mental disorders like anxiety and depression.[63]
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Creatine, through its ability to act as an energy reserve, attenuates neuron death induced by the MPTP toxin that can produce Parkinson’s disease-like effects in research animals,[235] reduces glutamate-induced excitotoxicity,[236] attenuates rotenone-induced toxicity,[120] L-DOPA induced dyskinesia,[237] 3-nitropropinoic acid,[238] and preserves growth rate of neurons during exposure to corticosteroids (like cortisol), which can reduce neuron growth rates.[239] Interestingly, the energetic effect also applies to Alzheimer’s disease, during which creatine phosphate per se attenuates pathogenesis in vitro, yet creatine per se did not.[240]
Men appear to have higher active creatine-kinase systems, and racial differences favor black people over hispanic people over white people in terms of the activity of the creatine-kinase system. This system is more variable in men, independent of supplementation. Exercise may increase the activity of the creatine-kinase system independent of supplementation.
A double-blind study provided 20 g/day of creatine monohydrate for 5 days to qualified sprinters and jumpers who performed 45 seconds of continuous jumping and 60 seconds of continuous treadmill running. Supplementation enhanced performance in the jumping test by 7% for the first 15 seconds and 12% for the next 15 seconds, but there was no difference for the final 15 seconds. There was a 13% improvement in the time of intensive running to exhaustion [12].
Young adult athletes who reported creatine usage for over two years prior to the study (retrospective design) were not significantly different than controls.[501] Elsewhere, in a similar cohort of athletes reporting creatine usage for up to four years, failed to note significant differences in liver enzymes, although a nonsignificant reduction in LDH was noted.[502]

Whenever you hear the word, “bodybuilding”, your mind usually flashes you images of bulging muscles, steel, sweat, the shouts of weightlifters, and ripped, muscular bodies of men and women in skimpy spandex. Your mind instantly takes you to the gym followed by wishful thinking that you can have a sexy body and bigger muscles. However, it takes more than just
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]