A great analogy that I like is that the balance between training and recovery is like digging a hole. Each time you lift, you dig yourself deeper and make it harder to climb out of the hole. To get back out again, you have to fill in the hole to return to ground level, and the only way to fill it is with food and rest. If you overdo it in the gym by pushing too hard, you won’t be able to train as often or at a high capacity. Eventually, you’ll get injured.

In muscle cells, the creatine transporter is predominantly localized to the sarcolemmal membrane. Western blot analysis of creatine transporter expression revealed the presence of two distinc protein bands, migrating at 55kDa and 70kDa on reducing SDS-PAGE gels.[147][148] The 73kDa band has been reported to be the predominant band in humans, with no differences based on gender.[148] A more recent report demonstrated that the 55kDa creatine transporter variant is glycosylated, forming the 73 kDa protein. Therefore, the 55 and 75kDa protein bands are actually immature and mature/processed forms of the creatine transporter protein, respectively.[149]

In addition to the BBB, SLC6A8 is also expressed on neurons and oligodendrocytes,[192] but is relatively absent from astrocytes, including the astrocytic feet[193][194] which line 98% of the BBB.[195] Creatine can still be transported into astrocytes (as well as cerebellar granule cells) via SLC6A8, as incubation with an SLC6A8 inhibitor prevents accumulation in vitro. It seems to be less active in a whole brain model, relative to other brain cells.[196]
One study investigating the effects of creatine supplementation on people with osteoarthritis undergoing knee arthroplasty (surgical procedure for osteoarthritis), who received creatine at 10g daily for 10 days prior to surgery and 5g daily for a month afterward, failed to find benefit with supplementation.[424] This study failed to find any differences in muscular creatine stores or weight changes.[424]
^ Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL (2017-06-13). "International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine". Journal of the International Society of Sports Nutrition. 14: 18. doi:10.1186/s12970-017-0173-z. PMC 5469049. PMID 28615996.
The genealogy of lifting can be traced back to the beginning of recorded history[1] where humanity's fascination with physical abilities can be found among numerous ancient writings. In many prehistoric tribes, they would have a big rock they would try to lift, and the first one to lift it would inscribe their name into the stone. Such rocks have been found in Greek and Scottish castles.[2] Progressive resistance training dates back at least to Ancient Greece, when legend has it that wrestler Milo of Croton trained by carrying a newborn calf on his back every day until it was fully grown. Another Greek, the physician Galen, described strength training exercises using the halteres (an early form of dumbbell) in the 2nd century.
xEndurance’s Creatine-JB is a fantastic, all-natural creatine for athletes. It’s a little expensive at a dollar per serving, but it has a really pleasant citrus flavor and it contains a gram of lactate, which has been shown in some studies to improve time to exhaustion in short duration, high intensity workouts. It’s also third party tested by Labdoor and Informed Choice.
Carbohydrates provide quick energy in an anaerobic environment (high-intensity exercise), while fats provide sustained energy during periods of high oxygen availability (low-intensity exercise or rest). The breakdown of carbohydrates, fats, and ketones produces ATP (adenosine triphosphate). When cells use ATP for energy, this molecule is converted into adenosine diphosphate (ADP) and adenosine monophosphate (AMP). Creatine exists in cells to donate a phosphate group (energy) to ADP, turning this molecule back into ATP.[20][21][22][23]
For the sake of mental focus, it’s best to keep any carbs you eat low during the day when you’re working and active and get the lion’s share of them at night with dinner. A typical breakfast could include eggs, yogurt, and fruit, or a shake, and lunch could be meat or fish and steamed veggies. For dinner, have meat or fish again, along with sweet potatoes or rice, and vegetables.
Women who train hard and reach low body fat levels, say under 10 percent, may be at risk of losing their periods as a result of hormonal disruption to estrogen production. Exercise-induced estrogen declines can result in bone loss in a way similar to that which occurs at the menopause. Loss of periods from athletic training is not uncommon but does require that you see a doctor, or better still, a sports physician and sports nutritionist to assess what is required to address the problem. Calcium supplements may be a part of the solution if bone health is likely to be affected. 
Creatine ethyl ester increases muscle levels of creatine to a lesser degree than creatine monohydrate.[72] It may also result in higher serum creatinine levels[73] due to creatine ethyl ester being converted into creatinine via non-enzymatic means in an environment similar to the digestive tract.[74][75] At equal doses to creatine monohydrate, ethyl ester has failed to increase water weight after 28 days of administration (indicative of muscle deposition rates of creatine, which are seemingly absent with ethyl ester).[76] 
The first thing you need is a weight training program that signals the muscle building process to begin. Research has shown that a well designed program will generate this “signal” via a combination of progressive tension overload (as in, getting stronger over time), metabolic stress (as in, fatiguing the muscle and getting “the pump”), and muscular damage (as in, actual damage to the muscle tissue itself).
I know this goes against the recommendations you often see in stereotypical bodybuilding routines (i.e. the ones that involve having a single “chest day” or “arm day” or “shoulder day” once a week), but that’s just one of the many reasons why those types of routines suck for us natural, genetically-average people, and work best for steroid users with great genetics.
Creatine is a hydrophilic polar molecule that consists of a negatively charged carboxyl group and a positively charged functional group [64]. The hydrophilic nature of creatine limits its bioavailability [65]. In an attempt to increase creatines bioavailability creatine has been esterified to reduce the hydrophilicity; this product is known as creatine ethyl ester. Manufacturers of creatine ethyl ester promote their product as being able to by-pass the creatine transporter due to improved sarcolemmal permeability toward creatine [65]. Spillane et al [65] analyzed the effects of a 5 days loading protocol (0.30 g/kg lean mass) followed by a 42 days maintenance phase (0.075 g/kg lean mass) of CM or ethyl ester both combined with a resistance training program in 30 novice males with no previous resistance training experience. The results of this study [65] showed that ethyl ester was not as effective as CM to enhance serum and muscle creatine stores. Furthermore creatine ethyl ester offered no additional benefit for improving body composition, muscle mass, strength, and power. This research did not support the claims of the creatine ethyl ester manufacturers.