Take time to rest. To give your muscles time to recover, rest one full day between exercising each specific muscle group. You might choose to work the major muscle groups at a single session two or three times a week, or plan daily sessions for specific muscle groups. For example, on Monday work your arms and shoulders, on Tuesday work your legs, and so on.
The harder an exercise is – both in terms of technicality and physical/mental demand – the more rest there should usually be. So exercises like squats and deadlifts should have more rest between sets than exercises like leg extensions and leg curls. And exercises like various bench presses, shoulder presses, rows and pull-ups should have more rest between sets than bicep curls, tricep extensions, chest flies and lateral raises.
The creatine transporter is a sodium and chloride dependent membrane-associated transporter that belongs to the Na+/Cl-dependent family of neurotransmitter transporters. In muscle cells and most other cell types, the isomer of the creatine transporter is known as SLC6A8 (solute carrier family 6, member 8). SLC6A8 is encoded by the gene present on the Xq28 region of the human X-chromosome and is expressed in most tissues. A related gene encoding a creatine transporter variant has also been identified at 16p11.1 that is expressed exclusively in the testes. These two transporters share 98% homology.
One supplement, which a large body of research has proven effective in building muscle mass when combined with intensive strength training, is creatine (sold as creatine monohydrate). Creatine, a source of rapid energy, is stored in the muscles in small amounts. With creatine loading or supplementation, bodybuilders increase muscle stores of the energy-containing compound which then can be used to provide an extra boost for an intense-high-weight lifting session. Studies support that ingestion of a relatively high dose of creatine (20 to 30 grams per day for up to two weeks) increases muscle creatine stores by 10 to 30 percent and can boost muscle strength by about 10 percent when compared with resistance training alone (Rawson & Volek, 2003). Some athletes report (though research does not necessarily support) muscle cramping in response after using creatine supplements.
Perform the exercise pairs (marked A and B) as alternating sets, resting 60 seconds between sets. You’ll complete one set of exercise A and rest; then one set of B and rest again; and repeat until you’ve completed all sets for that pair. On your very first training day, perform only one set for each exercise. Progress to two or more sets (as the set prescriptions below dictate) from your second workout on.
MET-Rx Advanced Creatine Blast also contains a lot of ingredients that work synergistically with creatine. There’s the 33 grams of carbohydrates, which may help to drive creatine to the muscles, plus there’s some taurine to help with recovery and two grams of branched chain amino acids, which may help with muscle retention. However, it contains creatine ethyl ester, which is probably less effective than monohydrate.
Creatine is stored in the body in the form of creatine and as creatine phosphate, otherwise known as phosphocreatine, which is the creatine molecule bound to a phosphate group. Creatine phosphate is thought to maintain the ATP/ADP ratio by acting as a high-energy phosphate reservoir. The more ATP a muscle has relative to ADP, the higher its contractility is, and thus its potential strength output in vivo. This pro-energetic mechanism also affects nearly all body systems, not just skeletal muscle.  During periods of rest and anabolism, creatine can gain a phosphate group through the creatine-kinase enzyme pathway, up to a cellular concentration of 30uM to be later used for quick ATP resupply, when needed.
“There is a lot of mixed research on creatine’s ability to improve muscle strength,” the government website says. “However, analyses of this research show that creatine seems to modestly improve upper body strength and lower body strength in both younger and older adults.” Creatine has also been shown to improve athletes’ performance in rowing, soccer, and jumping height.
In regard to the blood brain barrier (BBB), which is a tightly woven mesh of non-fenestrated microcapillary endothelial cells (MCECs) that prevents passive diffusion of many water-soluble or large compounds into the brain, creatine can be taken into the brain via the SLC6A8 transporter. In contrast, the creatine precursor (guanidinoacetate, or GAA) only appears to enter this transporter during creatine deficiency. More creatine is taken up than effluxed, and more GAA is effluxed rather than taken up, suggesting that creatine utilization in the brain from blood-borne sources is the major source of neural creatine. However, “capable of passage” differs from “unregulated passage” and creatine appears to have tightly regulated entry into the brain in vivo. After injecting rats with a large dose of creatine, creatine levels increased and plateaued at 70uM above baseline levels. These baseline levels are about 10mM, so this equates to an 0.7% increase when superloaded. These kinetics may be a reason for the relative lack of neural effects of creatine supplementation in creatine sufficient populations.