^ Jump up to: a b c d e f g h Momaya A, Fawal M, Estes R (April 2015). "Performance-enhancing substances in sports: a review of the literature". Sports Med. 45 (4): 517–531. doi:10.1007/s40279-015-0308-9. PMID 25663250. Wilson et al.  demonstrated that when non-resistance trained males received HMB pre-exercise, the rise of lactate dehydrogenase (LDH) levels reduced, and HMB tended to decrease soreness. Knitter et al.  showed a decrease in LDH and creatine phosphokinase (CPK), a byproduct of muscle breakdown, by HMB after a prolonged run. ... The utility of HMB does seem to be affected by timing of intake prior to workouts and dosage .
de Salles Painelli V, Alves VT, Ugrinowitsch C, et al. Creatine supplementation prevents acute strength loss induced by concurrent exercise. Eur J Appl Physiol 2014;114:1749-55.del Favero S, Roschel H, Artioli G, et al. Creatine but not betaine supplementation increases muscle phosphorylcreatine content and strength performance. Amino Acids 2012;42:2299-305. View abstract.
Gualano, B., de, Salles Painelli, V, Roschel, H., Lugaresi, R., Dorea, E., Artioli, G. G., Lima, F. R., da Silva, M. E., Cunha, M. R., Seguro, A. C., Shimizu, M. H., Otaduy, M. C., Sapienza, M. T., da Costa, Leite C., Bonfa, E., and Lancha Junior, A. H. Creatine supplementation does not impair kidney function in type 2 diabetic patients: a randomized, double-blind, placebo-controlled, clinical trial. Eur.J.Appl.Physiol 2011;111(5):749-756. View abstract.
Zinc is important to produce the male hormone testosterone and in building the immune system. Magnesium is an essential component of the nervous system and for maintaining heart health. Both have a range of important biochemical function. Zinc and magnesium are often marketed to bodybuilders in combination in a supplement called ZMA. Zinc is in whole grains, seeds, nuts and particularly meat and oysters. After years of research, no evidence exists to show that either mineral offers bodybuilding or athletic performance enhancement in excess of the recommended dietary requirements.
Jason Ferruggia is a highly sought after, world renowned strength & conditioning specialist and muscle building expert. Over the last 17 years he has personally trained more than 700 athletes from over 90 different NCAA, NFL, NHL and MLB organizations. He has also worked extensively with firefighters, police officers, military personnel, Hollywood stars and entertainers. Most importantly, Jason has helped over 53,000 skinny guys and hard gainers in 126 different countries build muscle and gain weight faster than they every thought possible.
Creatine is only taken up by its transporter, and changes in the activity level of this transporter are wholly causative of changes in creatine uptake. The transporter is regulated by mostly cytosolic factors as well as some external factors that affect creatine transport activity,  including extracellular creatine. Agents affecting creatine transport are further divided into positive regulators (those that increase activity of the transporter) and negative regulators (those that suppress activity).
In young rats given creatine in the diet at 2% of the diet for eight weeks, supplementation appears to increase bone mineral density (BMD) in the lumbar spine with a nonsignificant trend to increase BMD in the femur. Despite the trend, the femur appeared to be 12.3% more resistant to snapping from mechanical stress associated with increased thickness. Menopausal rats (ovarectomized) experience similar benefits, as supplementation of creatine (300mg/kg) for eight weeks during ovarectomy is able to increase phosphorus content of the bone and other biomarkers of bone health, although bone stress resistance was not tested.
One pilot study using 150mg/kg creatine monohydrate for a five day loading phase followed by maintenance (60mg/kg) for the remainder of the five weeks noted that supplementation was associated with fewer muscle symptoms and complaints alongside improved muscular function, yet a later trial trying to replicate the obsevations using 150mg/kg daily for five weeks noted the opposite, that creatine supplementation exacerbated symptoms.