The Effect Of Two Different Creatine Formulations On Skeletal Muscle Creatine Retention: 1905

Many creatine (CR) supplements contain dextrose, since early research suggested that a large insulin spike enhanced CR uptake into muscle. However, it has also been reported that CR uptake is primarily dependent upon sodium vs. insulin, which has led to the formulation of products that contain higher amounts of sodium and no dextrose; therefore, these products may also be Calorie free. Few studies have compared the efficacy of these 'sugar free' CR products to more traditional formulations that include dextrose. PURPOSE: To compare the effects of two different CR formulations on total skeletal muscle CR retention (TCR) following loading and maintenance doses. METHODS: 19 resistance trained men (X age ± SEM = 29±2 yr) randomly received one of two treatment conditions: (1) dextrose-free CR supplement containing 5g CR citrate and 250mg sodium (n = 9; SOD) or (2) a CR supplement containing 5g CR monohydrate and 36g dextrose (n = 10; DEX). Each treatment was dissolved in 16oz water and ingested 4 times per day for 5d (loading) followed by 5 g/d for 28d (maintenance). Body weight (BW) was measured using a calibrated physician's scale and muscle biopsies were obtained from the vastus lateralis using a fine needle aspiration technique at baseline (BL) and following the loading and maintenance doses for the determination of free CR (fCR) and phosphocreatine (PCR). The data were analyzed using 2x3 ANOVA (p