Creatine and creatine forms intended for sports nutrition

Abstract

Creatine is a popular ergogenic supplement in sports nutrition. Yet, supplementation of creatine occasionally caused adverse effects such as gastrointestinal complaints, muscle cramps and an increase in body weight. Creatine monohydrate has already been evaluated by different competent authorities and several have come to the conclusion that a daily intake of 3 g creatine per person is unlikely to pose safety concerns, focusing on healthy adults with exclusion of pregnant and breastfeeding women. Possible vulnerable subgroups were also discussed in relation to the safety of creatine. The present review provides an up-to-date overview of the relevant information with special focus on human studies regarding the safety of creatine monohydrate and other marketed creatine forms, in particular creatine pyruvate, creatine citrate, creatine malate, creatine taurinate, creatine phosphate, creatine orotate, creatine ethyl ester, creatine pyroglutamate, creatine gluconate, and magnesium creatine chelate. Limited data are available with regard to the safety of the latter creatine forms. Considering an acceptable creatine intake of 3 g per day, most of the evaluated creatine forms are unlikely to pose safety concerns, however some safety concerns regarding a supplementary intake of creatine orotate, creatine phosphate, and magnesium creatine chelate are discussed here.

Searching for a better formulation to enhance muscle bioenergetics: A randomized controlled trial of creatine nitrate plus creatinine vs. creatine nitrate vs. creatine monohydrate in healthy men

“…Many innovative creatine supplements have been evaluated for effectiveness and safety during the past decade or so, with most (Jagim et al, 2012) while several creatine analogs have shown significant side effects and limited applicability (Andres et al, 2017).…”

Effect of creatine ethyl ester supplementation and resistance training on hormonal changes, body composition and muscle strength in underweight non-athlete men

“…A daily dose of 0.5 to 5 grams is recommended at a maximum dose of 30 grams. No adverse effects were reported on body weight, liver, kidney, or histopathological analyses of some organs, including the liver and kidneys, in mice receiving an equivalent of 30 grams per person of 70 kg for 7 days [1]. The role of CEE is not well defined; studies have shown that CEE is converted to creatine in the body and increases the level of phosphate [30].…”

“…However, creatine supplementation sometimes causes side effects such as gastrointestinal complications, muscular cramps and weight gain. Most studies have been done on creatine monohydrate [1]. Creatine supplementation increases the amount of muscle creatine (20 to 40%) in individuals with low muscle creatine levels [10].…”

“…Creatine has several forms and one of its types is creatine ethyl ester (CEE). CEE is an ethanol esterified with creatine and may improve bioavailability [1]. CEE seems to be a new substrate for creatine kinase, and the production forms phosphocreatine ethyl ester, which may be a source of energy in the muscles and brain [1].…”

Efeito da suplementação de creatina sobre marcadores de lesão muscular e desempenho físico em atletas de voleibol

“…No início século XX, as pesquisas evoluíram e foi descoberto que nem toda a Cr consumida por fontes exógenas era expelida na urina e que parte da mesma era aproveitada pelo organismo. Além disso, ela também é sintetizada pelos rins, fígado e pâncreas por meio dos aminoácidos arginina, glicina e metionina (WYSS;DAOUK, 2000;MENDES;TIRAPEGUI, 2002;ANDRES et al 2016). Estudo feito por Lukaszuk et al (2002) mostrou que pessoas que retiraram produtos cárneos de sua alimentação, apresentaram uma baixa significativa desta substância no organismo, confirmando que a Cr também é obtida por fontes exógenas.…”