Journal of Physical Activity Research, 2018, Vol. 3, No. 2, 96-101 Available online at http://pubs.sciepub.com/jpar/3/2/6 ©Science and Education Publishing DOI:10.12691/jpar-3-2-6 Short-term Effects of Whey, Creatine, and L-carnitine Supplementation on Muscle Hypertrophy Marker Candidates in Young Males: A Randomized Placebo-controlled Pilot Study Bagus Sarmito 1 , Felicia Kartawidjajaputra 2,* , Antonius Suwanto 1 1 Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jakarta, Indonesia 2 Nutrifood Research Center, PT Nutrifood Indonesia, Jakarta, Indonesia *Corresponding author: felicia@nutrifood.co.id Received August 13, 2018; Revised October 04, 2018; Accepted October 29, 2018 Abstract Previous research showed that resistance exercise could induce muscle development, noticeably from the increased level of several markers from blood samples. However, no study had been performed to explore the effect of combination of resistance exercise and proper nutrition supply on those markers. The aim of this study to investigate the effect of whey protein, creatine, and L-carnitine; on potential molecular markers of muscle hypertrophy (arg1 and mmp9) from blood samples. Twelve healthy male participants were randomly categorized into supplement (SUPP) or placebo (PLAC) treatment, and performed resistance training three times in a one-week period. Blood sampling was carried out before (day one) and 2 hours after the exercise (day one, day three and day five). The level of mmp9 gene expression was increased along with the progress of the resistance training program. Moreover, participants who received supplementation (SUPP) showed a higher level of mmp9 gene expression compared to resistance training only (PLAC). A significant difference was observed between two treatments in the first day, 2 hours after the resistance training session (p = .04); and between SUPP group on the fifth day, 2 hours after the resistance training; compared to the first day, before the resistance training session (p = .02). The effect was not observed on arg1 gene. A combination of resistance training with supplementation; was considered to enhance the muscle hypertrophy process, compared to resistance training only. The results also suggested that mmp9 could act as a blood-derived molecular marker of muscle hypertrophy. Keywords: muscle hypertrophy, resistance training, whey protein, L-carnitine, mmp9, arg1 Cite This Article: Bagus Sarmito, Felicia Kartawidjajaputra, and Antonius Suwanto, “Short-term Effects of Whey, Creatine, and L-carnitine Supplementation on Muscle Hypertrophy Marker Candidates in Young Males: A Randomized Placebo-controlled Pilot Study.” Journal of Physical Activity Research, vol. 3, no. 2 (2018): 96-101. doi: 10.12691/jpar-3-2-6. 1. Introduction Resistance training is a kind of sport which can improve general fitness status and induce muscular hypertrophy, by performing movements against force in the opposite direction. Studies showed positive effects of resistance exercise to muscle cross-sectional area, cellular markers, protein markers, and gene expression markers; yet, muscle biopsy was still the method of preference for sampling [1,2,3]. Muscle biopsy is known as an invasive method and potential to cause a scar in the participant’s body. Therefore, molecular markers from blood sample are preferable because they give less invasive effect to the participants. Research showed that there were two genes which upregulated in 2 hours after acute resistance exercise: arg1 and mmp9 [4]. Those genes were analyzed from blood samples. Arginase-1 (Arg1) is an enzyme which metabolizes arginine to ornithine, which furtherly modified to proline, a constituent of collagen which important in hypertrophy process [5,6,7]. Meanwhile, matrix metalloproteinase 9 (MMP9, gelatinase B) is an enzyme which is capable of degrading extracellular matrices, particularly type IV and V collagen [8,9]. This enzyme helps the movement of leukocytes toward the damaged area of muscle tissue, improve the ability of myoblast migration, and help the synthesis of new myofiber [10,11]; thus, the hypertrophy process can occur. The combination of resistance training and proper nutrition supply will help the body-builders to achieve enhanced muscular development. Administration of nutrients, particularly whey protein, creatine, and L-carnitine would further enhance the process of muscle hypertrophy. Researches showed that whey protein and creatine could improve myoblast proliferation and differentiation [12,13]. Meanwhile, L-carnitine was involved in muscle recovery