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.

The 100% Grass-Fed Whey Protein Isolate comes in the form of powder and can be mixed with any liquid. While the protein powder can be mixed well with water, try mixing it with milk for added calories and protein. You can even add this to smoothies and baked goods to increase the protein profile. Recommended protein intake for adults is 0.8 grams per kilogram. Some athletes may need as much as 1.2-2 grams protein per kilogram. For your specific needs, always consult a registered dietitian.

Spillane M, Schoch R, Cooke M, Harvey T, Greenwood M, Kreider R, Willoughby DS. The effects of creatine ethyl ester supplementation combined with heavy resistance training on body composition, muscle performance, and serum and muscle creatine levels. J Int Soc Sports Nutr. 2009;6:6. doi: 10.1186/1550-2783-6-6. [PMC free article] [PubMed] [CrossRef]

Still, it's important to realize that for everyone, at a certain point, building muscle becomes more difficult. "We all have an endpoint to our genetic potential," Matheny says. "Someone who is starting strength training for the first time can build muscle with a lower percentage of their 1RM [the maximum amount of weight they can lift one time] than a more tenured athlete. The longer you train and the closer you to get to your natural potential, the more specific you need to get with your training and nutrition to keep making progress. And that week-by-week progress will likely be much smaller than it once was."

If you're a beginner, just about any workout will be intense enough to increase protein synthesis. But if you've been lifting for a while, you'll build the most muscle quickest if you focus on the large muscle groups, like the chest, back, and legs. Add compound lifts like squats, deadlifts, pullups, bent-over rows, bench presses, dips, and military presses to your workout to work them the most efficiently.
Testosterone was first used as a clinical drug as early as 1937, but with little understanding of its mechanisms. The hormone is now widely prescribed to men whose bodies naturally produce low levels. But the levels at which testosterone deficiency become medically relevant still aren’t well understood. Normal testosterone production varies widely in men, so it’s difficult to know what levels have medical significance. The hormone’s mechanisms of action are also unclear.
There are also many other variations of squats you can try. Squats can be done with weights held in the front of your body or behind your back, using dumbbells or a stability ball, with your arms held overhead or parallel to the floor, using a chair or wall for support if you’re more limited, held in place while you focus on breathing (as is done in yoga during “chair pose”), and in other ways. Pistol squats are also a great workout for the entire legs and hips. Pistols are one-legged squats with one relaxed hamstring and calf and the other leg straight out in front of you as you lower down.
Perhaps 1 to 2% of intramuscular creatine is degraded into creatinine each day, which is excreted in urine. Therefore, approximately 1 to 3 g of creatine needs replenishing daily to maintain basal levels. Some of this replacement is fulfilled by the liver and kidneys, which can use the amino acids arginine and glycine to synthesize creatine. A tiny minority of people has gene mutations that result in impaired creatine synthesis or transport. These unfortunate people experience severe neurodevelopmental problems beginning early in life and benefit from consuming more creatine in their diets.
Fast twitch (or Type II fibers) fire very quickly, but also fatigue quickly, so they don’t last long.  It gets a bit more complicated, because there are actually two types of fast twitch fibers. Type IIA fibers have some endurance qualities (used for things such as longer sprints). While Type IIX fibers are our “super fast” fibers, used only when a super short burst is needed (like a 100 m sprint or a really heavy lift).
Prison food isn’t as bad as people think. Prisoners often get three meals a day. Meals need to meet a certain amount of calories. You don’t need that much protein to build muscle, but prisoners can buy protein powder (and also extra food like oatmeal). Prisoners aren’t underfed in most western countries. The diet may not be optimal, but it’s sufficient to build muscle.

Macrophages are known to express creatine kinase[290] and take creatine up from a medium through a sodium dependent mechanism (likely the creatine transporter) in a saturable manner,[435] with a second component that requires there to be no concentration gradient to work against (likely passive diffusion) but this effect tends to only account for up to 10% of total uptake in the physiological range (20-60µM).[435] Supraphysiological range was not tested.
A meta-analysis found that creatine treatment increased muscle strength in muscular dystrophies, and potentially improved functional performance.[57] Creatine treatment does not appear to improve muscle strength in people who have metabolic myopathies.[57] High doses of creatine lead to increased muscle pain and an impairment in activities of daily living when taken by people who have McArdle disease.[57]
Having a strong butt will get you far—literally. Our glutes are responsible for powering us through everything from long runs to tough strength workouts to a simple jaunt up a flight of stairs. Strong glutes that can take on the brunt of the work can help us avoid overcompensating with smaller muscles during lower-body exercises. Plus, beyond just helping us move, the glutes play an important role in "stabilizing our entire lumbo-pelvic-hip complex," says Cori Lefkowith, NASM-certified personal trainer and owner of Redefining Strength in Costa Mesa, California. That translates to better form, more efficient movement, and a reduced risk of straining your lower back and hips.