Mercimek-Mahmutoglu, S., Stoeckler-Ipsiroglu, S., Adami, A., Appleton, R., Araujo, H. C., Duran, M., Ensenauer, R., Fernandez-Alvarez, E., Garcia, P., Grolik, C., Item, C. B., Leuzzi, V., Marquardt, I., Muhl, A., Saelke-Kellermann, R. A., Salomons, G. S., Schulze, A., Surtees, R., van der Knaap, M. S., Vasconcelos, R., Verhoeven, N. M., Vilarinho, L., Wilichowski, E., and Jakobs, C. GAMT deficiency: features, treatment, and outcome in an inborn error of creatine synthesis. Neurology 8-8-2006;67:480-484. View abstract.
Use regular creatine monohydrate. Go for batch-tested stuff with the label Creapure®. This brand is a good option. Don’t bother with other forms like citrate, ethyl ester, or nitrate. And avoid prepared drinks with creatine as an ingredient: When creatine remains in solution it soon degrades to creatinine, especially at higher temperatures and lower pH values.
For example, a 2015 review published in the peer-reviewed journal Applied Physiology, Nutrition, and Metabolism suggests that, for maximal muscle growth, people consume 25 to 35 grams of protein at breakfast, lunch and dinner. You'll find that amount of protein in a chicken breast, a cup of Greek yogurt with slivered almonds or about a three-quarter block of tofu.
The concentration in healthy controls (57+/-8 years) without supplementation of creatine appears to be around 1.24+/-0.26µM per gram of hemoglobin and appears to decrease in concentration during the aging process of the erythrocyte. Otherwise healthy subjects who take a loading phase of creatine (5g four times daily for five days) can experience a 129.6% increase in erythrocytic creatine concentrations from an average value of 418µM (per liter) up to 961µM with a large range (increases in the range of 144.4-1004.8µM), and this effect appears to correlate somewhat with muscular creatine stores.
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.