Tough workouts drive muscle growth, but they generally cause a lot of damage to your muscles to do so. This damage often results in soreness for several days, which can make it tough to get to the gym or sometimes even move. Many bodybuilding supplements contain ingredients that work to reduce the breakdown of muscle during workouts, making the recovery process easier on the body.
Kidney damage (from anything) will cause high levels of creatinine in blood, and creatine can also increase blood creatinine levels in a manner that is not due to damaging the kidneys. This results in a false positive when trying to diagnose kidney damange when the subject also supplements creatine, and does not signify any actual damage to the kidneys.
It’s important to remember that since everybody is different, these estimates are just that. How the numbers work out for each person will definitely vary. So many factors—like genetics, hormones, sleep, and diet—can change the rate at which our bodies burn calories. And some people may have a harder time than others when it comes losing fat or gaining muscle—again, there are so many factors at play and our body chemistries are all different. Strength training is important for many, many, many other reasons (more on that later), but if you’re looking to increase your metabolism, it’s important to have realistic expectations and know that strength training can make a difference, but probably won’t drastically affect how many calories you burn from one day to the next. 

Creatine has been incubated in various cell lines (HUVEC, C2C12, U937) and noted to reduce cellular death from various pro-oxidant stressors, such as H2O2 or peroxynitrate in an intracellular range between 0.1-10mM. This protective effect was only noted with preincubation and was comparable to 10-100µM of Trolox.[208] This protective effect did not require conversion into phosphocreatine nor a buffering of ATP, and only worked during a preloading to the stressor, rather than in a rehabilitative manner.[208]
Long popular among bodybuilders, casein protein absorbs slowly into the bloodstream, meaning it keeps your muscles fed with amino acids for longer compared to other types of protein such as whey and plant proteins. In one Medicine and Science in Sports and Exercise study, consuming casein protein immediately before bed boosted young men’s levels of circulating amino acids for 7.5 hours; they built muscle all night long while they slept.
Athletes in ancient Greece were advised to consume large quantities of meat and wine. A number of herbal concoctions and tonics have been used by strong men and athletes since ancient times across cultures to try to increase their strength and stamina.[5] In the 1910s, Eugen Sandow, widely considered to be the first modern bodybuilder in the West, advocated the use of dietary control to enhance muscle growth. Later, bodybuilder Earle Liederman advocated the use of "beef juice" or "beef extract" (basically, consomme) as a way to enhance muscle recovery. In 1950s with recreational and competitive bodybuilding becoming increasingly popular Irvin P. Johnson began to popularize and market egg-based protein powders marketed specifically at bodybuilders and physical athletes. The 1970s and 1980s marked a dramatic increase in the growth of the bodybuilding supplement industry, fueled by widespread use of modern marketing techniques and a marked increase in recreational bodybuilding.
Beta-alanine is a naturally occurring non-essential amino acid that comes into the body through foods that are rich in protein. The performance-enhancing aspect of beta-alanine (BA) is due to its ability to increase intra-muscular levels of carnosine. Increasing beta-alanine through supplementation may raise carnosine levels by over 60 percent in as quickly as four weeks.[6]
That means it takes time for supplements aimed at joint treatment to work. So plan not to feel anything for about two months after you start using glucosamine. After that, pain control with the supplement is comparable to what happens with drug use, according to various studies. The typical doses are 1,200 milligrams daily of glucosamine and 800 of chondroitin, which can be doubled initially.

It is known that intracellular energy depletion (assessed by a depletion of ATP) stimulates AMPK activity in order to normalize the AMP:ATP ratio,[333][334] and when activated AMPK (active in states of low cellular energy[335] and colocalizes with creatine kinase in muscle tissue[336]) appears to inhibit creatine kinase via phosphorylation (preserving phosphocreatine stores but attenuating the rate that creatine buffers ATP). While phosphocreatine technically inhibits AMPK, this does not occur in the presence of creatine at a 2:1 ratio.[334] It seems that if the ratio of phosphocreatine:creatine increases (indicative of excess cellular energy status) that AMPK activity is then attenuated, since when a cell is in a high energy status, there is less AMP to directly activate AMPK.[334][336][337]