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Scivation Xtend Write-Up, FAQ, & Reviews By Derek Charlebois The idea of supplementing with extra branch-chained amino acids (BCAA) in addition to ones protein intake has been around for quite some time. But with all the 'magic elixirs' and 'pump potions' on the market today, BCAA supplementation has never gained popularity outside of the hardcore (as in elite athletes) circles. One reason for this oversight on BCAA may be that people feel supplementing with additional BCAA on top of an already high protein diet will not be beneficial. Others may simply be uninformed about BCAA. Whatever the case may be, it is time to take an in depth look at BCAA to see if they have a place in your supplement arsenal. Before you begin reading this article, I recommend you first read my article on "Amino Acid Metabolism", as it will give you the basics to understand the article at hand. What Are Branched-Chain Amino Acids? The BCAA Are A Group Of Three Essential Amino Acids: 1. Leucine 2. Isoleucine 3. Valine. The BCAA are different from the other 17 amino acids in that they are primarily metabolized in skeletal muscle (Layman, 2003) and metabolized at a much lower rate in the liver (Norton, 2005). The rate limiting enzyme in BCAA catabolism is Branched Chain Keto Acid Dehydrogenase, which is much more active in skeletal muscle than in the liver (Norton, 2005). Because BCAA serve as a "fuel" for skeletal muscle, supplementing with additional BCAA to improve sports performance and to treat various diseases and aliments as been suggested. BCAA have many other roles besides being just a fuel for skeletal muscle. The Metabolic Roles Of The BCAA Include: Substrate for energy production Substrate for protein synthesis Precursor for the formation of other amino acids o Primarily Alanine and Glutamine Metabolic signals (Primarily Leucine) o Stimulates protein synthesis through insulin secretion/activation of the PI3K pathway o Stimulates protein synthesis through activation of mTOR Stimulates leptin expression in adipocytes through activation of mTOR We will now examine briefly the BCAA's roles as substrates for energy production and protein synthesis then closely examine their roles in the formation of other amino acids and as metabolic signals. Substrate For Energy Production Point blank, exercise promotes increased BCAA oxidation (Shirmomura et al., 2004). This increased degradation of BCAA helps maintain energy homeostasis by providing carbon as a direct energy source and glucose homeostasis by providing substrates for the citric-acid cycle and gluconeogenesis. Amino acids are categorized as glucogenic, ketogenic, or a combination of glucogenic and ketogenic. A glucogenic amino acid when metabolized gives rise to pyruvate or other TCA cycle intermediates that can be used for the production of glucose through gluconeogenesis. A ketogenic amino acid is metabolized via the fatty acid pathway and gives rise to actyl-CoA, a fatty acid precursor. Leucine is completely ketogenic, valine is completely glucogenic, and isoleucine is both glucogenic and ketogenic. Valine and isoleucine can both be used to produce intermediates for glucose production via gluconeogenesis. Due to leucine's metabolic properties (discussed below), increasing attention is being given to it and its metabolism. Research has shown plasma leucine levels to decrease during both aerobic and anaerobic exercise (Mero, 1999). According to Freund and Hanani (2002), "Complete oxidation of leucine in the muscle yields more adenosine triphosphate molecules on a molar basis than complete oxidation of glucose." So leucine can provide skeletal muscle with more ATP than an equal amount of glucose, which is due to leucine being completely ketogenic and metabolized via the fatty acid pathway. In order to meet the increased demand for BCAA during exercise the body breaks down muscle tissue to supply additional BCAA. By supplying the body exogenous BCAA during exercise, one can meet the increased demand for BCAA oxidation without breaking down muscle tissue to supply the needed BCAA. Substrate For Protein Synthesis I am going to give a very brief overview of protein synthesis. A person's genetic code is contained in DNA, which is held in the nucleus of cells. DNA contains information that specifies the amino acid sequence for the synthesis of various proteins. Without going into detail, the process of creating a protein from DNA is as follows: DNA-Transcription --> RNA-Translation --> Protein During translation, amino acids from the intracellular amino acid pool are added to a growing protein chain. All three of the BCAA are essential amino acids, meaning the body cannot create them and they must be acquired from the diet. Simply put, adequate levels of all essential amino acids (and all amino acids for that matter, but the nonessential amino acids can be created by the body) are needed for protein synthesis to occur uninterrupted. An athlete should follow a diet with a sufficient protein intake for their needs. Precursor For The Formation Of Alanine & Glutamine The BCAA's are involved in maintaining glucose homeostasis through the glucose-alanine cycle (see figure 1). The glucose-alanine cycle involves pyruvate (derived from glucose) being transaminated in muscle to form alanine, with the BCAA serving as the main nitrogen source (donors) for the synthesis of alanine (Holecek, 2002). The newly synthesized alanine is released in the blood stream and sent to the liver where it is converted into glucose through gluconeogenesis. This glucose can then be sent from the liver back to the working muscle to be used as fuel. Click To Enlarge. Interorgan movement of branched-chain amino acids (BCAA), ALA, alanine; GIN, glutamine; Glu, glutamate; áKG, alpha-keto-glutarate. Figure 2 - Adapted from: Layman, DK (2003). The role of leucine in weight loss diets and glucose homeostasis. J. Nutr. 133: 261S-267S. The amino acid glutamine has multiple roles in the body. According to Houston (2001), "Glutamine content in skeletal muscle and other tissues appears to have a regulatory role in whole body protein synthesis." Glutamine levels inside muscle govern protein synthesis and nitrogen balance and therefore muscle gain (VanAcker et al. 1999). Glutamine is also a powerful cell volumizer (Haussinger et al. 1993). An increase in cell volume, also called cell swelling, stimulates many anabolic pathways (synthesis of protein and glycogen) and inhibits catabolic pathways (protein degradation) (Haussinger, 1996). Glutamine is a "nitrogen shuttle" between organs, a fuel for cells of the immune system and intestines, and a precursor for nucleotide synthesis (Holecek, 2002). Ingestion of supplemental free-form glutamine or glutamine peptides is oxidized by the intestinal tract or taken up by the liver and kidney, all of which is beneficial but supplementing with BCAA can cause de novo synthesis of glutamine inside skeletal muscle (Houston, 2001). The body's need for alanine and glutamine is increased during exercise is met by BCAA from muscle protein breakdown (Holecek, 2002). Increased muscle protein breakdown equates to muscle loss, which no athlete wants. By supplementing with BCAA, one can deliver the needed building blocks for both alanine and glutamine and spare muscle tissue. Stimulation Of Insulin Secretion, PI3K, & Protein Synthesis By Leucine One pathway through which protein synthesis can be increased is the phosphatodyl-inositol-3-kinase pathway (PI3K). PI3K regulates glucose uptake through GLUT4 translocation and also increases amino acid uptake. Insulin, the body's "storage" hormone, works by activating the PI3K pathway. Interestingly, leucine ingestion causes insulin secretion, but leucine can also directly activate PI3K in the absence insulin (Nishitani et al. 2002), suggesting leucine to have a synergistic role with insulin as a PI3K activator (Layman, 2002). So not only can leucine increase glucose uptake, it can also increase its own and other amino acids' uptake into cells. These facts suggest that taking additional BCAA with carbohydrates around ones workout will lead to a synergistic increase in glucose and amino acid uptake into skeletal muscle. Leucine can stimulate protein synthesis through insulin secretion and the activation of the PI3K pathway, but can also stimulate protein synthesis through other pathways. Activation Of mTOR By Leucine The Mammalian Target of Rapamycin (mTOR) is one of the body's protein synthesis regulators. MTOR functions as an energy sensor; it is activated when ATP levels are high and blocked when ATP levels are decreased (AMPK is activated when ATP decreases, which works antagonistically to mTOR). The main energy-consuming process in the cell is protein synthesis. When mTOR is activated (high ATP levels sensed) protein synthesis is increased and when mTOR is suppressed (low ATP levels are sensed) protein synthesis is blunted. MTOR activation is vital for skeletal muscle hypertrophy. Interestingly, mTOR is also a nutrient sensor of amino acid availability, specifically of leucine availability. Research has shown that regulation of mTOR by ATP and amino acids act independently through separate mechanisms (Dennis et al., 2001). Leucine is the key regulator of the mTOR-signaling pathway (Anthony et al. 2001 & Lynch et al. 2002). According to Laymen (2003), "The increase in leucine concentration is sensed by an element of the insulin-signaling pathway and triggers a phosphorylation cascade that stimulates the translational initiation factors eIF4 and p70S6K." (See figure 2) Activation of these initiation factors initiates the translation of muscle mRNA components and are vital for skeletal muscle protein synthesis and creation of new contractile proteins (muscle). Leucine directly signals and primes your muscles to grow through the activation of mTOR. Click To Enlarge. Insulin signaling cascade [adapted from Laymen (17) amd Anthony et at. (39)]. IRS1, Insulin receptor substrate 1; Pß-K, phosphatidylinostitol-3 kinase; GLUT4, Insulin-dependent glucose transporter; PKC, proteinkinase C; mTOR, mammial target of rapamycin; el F4, translational factor 4. Figure 3 - Adapted from: Layman, DK (2003). The role of leucine in weight loss diets and glucose homeostasis. J. Nutr. 133: 261S-267S. We see that leucine stimulates protein synthesis through both insulin secretion/activation of PI3K pathway and activation of the mTOR pathway, but there is still a third pathway through which leucine stimulates protein synthesis; a mTORindependent pathway that not much is known about (and hence will not be discussed in this article). Sign up for article updates here. Stimulation of Leptin Expression through mTOR activation in Adipocytes Intake of leucine stimulates expression of the hormone leptin in adipocytes (the primary site of leptin secretion) through activation of the mTOR pathway (Meijer and Dubbelhuis, 2003). Leptin is a very complicated hormone; the gist of it is involved in the regulation of metabolism, body weight, and appetite. Leptin secretion is linked with body fat levels; higher body fat is associated with higher leptin secretion and lower body fat is associated with lower leptin levels. When you diet and lose fat, the amount of leptin you secrete decreases, which makes your body "crave" food in an attempt to bring your body fat level back up to where the body is comfortable (known as the body fat "set point"). Leucine has the ability to activate leptin expression and will cause the body to think it is "fed" or receiving "adequate" calories, which will keep things running (specifically your metabolism) smoothly. Supplementing With BCAA What is interesting about the BCAA is their ability to participate in the above metabolic processes, energy substrates, substrates for protein synthesis, precursors for alanine and glutamine, and modulators of protein synthesis, is governed by their availability. Research suggests that first and foremost the BCAA are used for the synthesis of protein structures (Layman, 2003). Research on leucine shows that once the minimum requirement of leucine for protein synthesis is met leucine can then be used as a precursor for alanine and glutamine or to activate various signaling pathways (Layman, 2003), such as the mTOR pathway. It may sound like leucine is free to exert its powerful effect of mTOR activation, but one must remember that protein breakdown and synthesis is occurring throughout the entire body; the body's protein stores are in a constant state of flux. The constant body protein flux plus the increased leucine oxidation caused by exercise means that leucine is in high demand and therefore may not be able to participate in muscle growth at its full potential. This is where supplementing with additional BCAA comes into play and importance. Due to leucine's metabolic properties, many people focus solely on leucine and not the other two BCAAs valine and isoleucine. Research has shown that leucine-rich diets or administration of leucine alone lead to decreases in valine and isoleucine plasma concentrations and a BCAA imbalance (Shirmomura et al., 2004). While it may be cheaper to supplement with leucine alone instead of all three BCAA, one should supplement with all three BCAA so not to create a BCAA imbalance. The main question or argument with BCAA supplementation people have is whether additional BCAA supplementation on top of an already high protein intake will produce any benefits, specifically enough benefits justify to the cost of the BCAA. Research and anecdotal findings would definitely suggest yes. I feel that the benefits of free-form BCAA lie in their ability to quickly flood the blood stream and amino acid pools with high amounts of BCAA, specifically leucine. While whey protein is absorbed quickly, ingestion of 10 grams of BCAA from whey does not create the same metabolic response as the ingestion of 10 grams of free-form BCAA. Once whey protein reaches the gut, it takes about 45 minutes before the amino acids start to be extracted and are absorbed and can be used. This lower absorption means the amino acid pools are not "flooded" with large amounts of BCAA. Remember, the BCAA ability to be utilized in various pathways is governed by their availability. It is my belief that delivering large amounts of BCAA to muscle and keeping BCAA levels elevated will cause a strong and sustained activation of mTOR, leading to skeletal muscle hypertrophy. The current research available clearly displays that the BCAA (specifically leucine) are very potent stimulators of protein synthesis and have many other beneficial effects to athletes. In Summary, The Metabolic Roles Of The BCAA Include: Substrate for energy production Substrate for protein synthesis Precursor for the formation of other amino acids o Primarily Alanine and Glutamine Metabolic signals (Primarily Leucine) o Stimulates protein synthesis through insulin secretion/activation of the PI3K pathway o Stimulates protein synthesis through activation of mTOR o Stimulates leptin expression in adipocytes through activation of mTOR What all this means is ingesting BCAA primes your body for growth (protein synthesis). All of these actions are beneficial to an athlete and should not be overlooked. There is endless research backing BCAA supplementation. I feel it would be much more beneficial, both performance/results wise and money wise, to go "old school" and supplement with BCAA than to buy into all the current hype supplements on the market today. References: 1. Anthony JC, Anthony TG, Kimball SR, Jefferson LS. Signaling pathways involved in translational control of protein synthesis in skeletal muscle by leucine. J Nutr. 2001 Mar;131(3):856S-860S. 2. Dennis, PB. Jaescke, A., Saitoh, M., Fowler, B., Kozma, SC., Thomas, G. (2001). Mammalian TOR: A homeostatic ATP sensor. Science. 294: 1102-1105. 3. Haussinger D et al. Cellular hydration state: An important determinant of protein catabolism in health and disease. Lancet 341:1330-1332.1993. 4. Houston, Michael (2001). Biochemistry Primer for Exercise Science (2nd Ed.). Illinois: Human Kinetics 5. Layman DK (2002). Role of leucine in protein metabolism during exercise and recovery. Can J Appl Physiol. Dec;27(6):646-63. 6. Layman, DK (2003). The role of leucine in weight loss diets and glucose homeostasis. J. Nutr. 133: 261S-267S. 7. Lynch CJ, Patson BJ, Anthony J, Vaval A, Jefferson LS, Vary TC. Leucine is a direct-acting nutrient signal that regulates protein synthesis in adipose tissue. Am J Physiol Endocrinol Metab. 2002 Sep;283(3):E503-13. 8. Mero A. (1999) Leucine supplementation and intensive training. Sports Med. 1999 Jun;27(6):347-58. 9. Nishitani S, Matsumura T, Fujitani S, Sonaka I, Miura Y, Yagasaki K. (2002). Leucine promotes glucose uptake in skeletal muscles of rats. Biochem Biophys Res Commun. Dec 20;299(5):693-6. 10. Norton, L. (2005) Soon to be published data, will add reference when the journal article is published. 11. Shimomura, Y. Murakami, T.Nakai, N. Nagasaki, M. Harri, R.A. (2004). Exercise Promotes BCAA Catabolism: Effects of BCAA Supplementation on Skeletal Muscle during Exercise J. Nutri. 134: 1583S-1587S. 12. VanAcker BA,.et al. (1999) Glutamine:the pivot of our nitrogen economy? JPEN, 23:S45-8. What is Xtend? Xtend is a precise, scientific blend of “Energy Aminos” consisting of the proven 2:1:1 ratio of Branched Chain Amino Acids (L-Leucine, L-Isoleucine and L-Valine), Glutamine, Citrulline Malate, and Vitamin B6. For more information on BCAA, read: http://www.bodybuilding.com/fun/beast11.htm http://www.bodybuilding.com/fun/beast14.htm For more information on Citrulline Malate, read: http://www.bodybuilding.com/fun/jrod3.htm http://www.bodybuilding.com/fun/jrod4.htm For more information on Glutamine, read: http://www.bodybuilding.com/fun/inmag6.htm http://www.bodybuilding.com/fun/inmag8.htm If I already eat a lot of protein, will additional free-form BCAA be beneficial to me? The metabolic effects seen from ingesting free-form amino acids are different from ingesting the same amino acids when they are in a whole protein (peptide bond). The rapid flushing of the system with the particular amino acid exerts a much more powerful activation of its target pathways. For example, if you were to ingest 5 grams of free-form arginine pre-workout you would notice a greater pump then without it. If you were to ingest 5 grams of arginine in the form of a whole protein (1) you’d have to eat a ton of protein to acquire the 5 grams of arginine and (2) the rate of delivery would be much slower and (3) you would not be flooding your system with a large dose of arginine at one time. The same holds true for BCAA. Ingesting 10 grams of BCAA will lead to greater activation of mTOR, PI3K, etc.* than ingesting 10 grams of BCAA from a whole protein. *refer to my BCAA for more info on these pathways: http://www.bodybuilding.com/fun/beast11.htm What if I already take in a lot of whey protein which is high in BCAA? Free-form amino acids are absorbed quicker than whey, and as stated above, whey will not flood your bloodstream with BCAA as quick as ingesting free-form BCAA. The BCAA from whey compared to free-form BCAA could be compared to filling up a glass of water from a garden hose (whey) to a faucet (free-form BCAA). If you use a garden hose you have to wait until the water travels the length of the hose before you can use it. With a faucet, the water is right there when you turn it on. On top of this, the faucet has a wider opening than the garden hose and releases more water than the garden hose. During your workout and times of stress (dieting), you want the BCAA to get to your muscles as quickly as possible. I have heard one can get the same effects from taking Leucine alone as from taking all 3 BCAA, is this true? Due to leucine's metabolic properties, many people focus solely on leucine and not the other two BCAAs, valine and isoleucine. Research has shown that leucine-rich diets or administration of leucine alone lead to decreases in valine and isoleucine plasma concentrations and a BCAA imbalance (Shirmomura et al., 2004). While it may be cheaper to supplement with leucine alone instead of all three BCAA, one should supplement with all three BCAA so not to create a BCAA imbalance. Isoleucine and Valine also has some interesting properties of their own, separate from leucine. Isoleucine has been shown to increase glucose intake via PI3K activation, one of the same pathways leucine uses, but independently of the mTOR pathway (Doi et al., 2003). Valine has been shown to reduce fatty acid synthase in adipocytes by 40%, which will lead to less fat storage (Taylor & Halperin, 1975). How much and when should I take Xtend? How much Xtend you take per day will depend primarily on how much money you can spend and your goals. The following dosing protocols are based on the large tub of Xtend, which has 90 servings. Servings per day 1 2 3 4 5 6 7 8 9 10 1 Jug will last (days) 90 45 30 22.5 18 15 12.86 11.25 10 9 3 Servings during Your Workouts Strategy During exercise BCAA oxidation is increased. Supplementing with additional BCAA spares muscle tissue from being broken down to acquire BCAA. Therefore, drinking Xtend around and during your workout is the ideal way to use it. Start sipping your Xtend 15 minutes prior to the start of your workout (i.e. while driving to the gym). Continue sipping Xtend between sets during your workout and finish whatever Xtend you have not drunken immediately post workout. Follow this up with your usual post-workout shake or meal. If you only use Xtend during your workouts, 1 jug will last as follows: 3 Servings sipped pre/during/post workout # of workouts per week 1 Jug will last (weeks) 1 30 2 15 3 10 4 7.5 5 6 6 5 7 4.285714286 If you want to take additional Xtend on your rest days to accelerate recovery and growth, 1 jug will last: Rest Day 3 Servings sipped pre/during/post workout Servings # of workouts per Workout Servings 1 per Rest Total Servings Per 1 Jug will last week Per Week Day Week (weeks) 1 3 6 9 10.00 2 6 5 11 8.18 3 9 4 13 6.92 4 12 3 15 6.00 5 6 7 15 18 21 2 1 0 17 19 21 5.29 4.74 4.29 # of workouts per week 1 2 3 4 5 6 7 Workout Servings Per Week 3 6 9 12 15 18 21 2 per Rest Day 12 10 8 6 4 2 0 Total Servings Per Week 15 16 17 18 19 20 21 1 Jug will last (weeks) 6.00 5.63 5.29 5.00 4.74 4.50 4.29 # of workouts per week 1 2 3 4 5 6 7 Workout Servings Per Week 3 6 9 12 15 18 21 3 per Rest Day 18 15 12 9 6 3 0 Total Servings Per Week 21 21 21 21 21 21 21 1 Jug will last (weeks) 4.29 4.29 4.29 4.29 4.29 4.29 4.29 Sipping Xtend throughout the Day Strategy Another popular method for using Xtend is to sip it throughout the day. Many users of this method have reporting gaining lean mass while losing fat simultaneously. This method would be ideal for those cutting on a low-carb, hypocaloric diet. Simply put the desired amount of Xtend in a container (i.e. gallon jug) and drink from it occasionally throughout the day. I would recommend using 4-6 scoops in a gallon jug as pictured here: If you use 3 servings (6 scoops) per day in this manner, 1 jug of Xtend will last 30 days. If you combine this method with the above method of taking 3 servings of Xtend during your workout, 1 jug will last: 3 Servings in Gallon Jug + 3 Servings During Workout # of workouts per Workout Gallon Jug Total Servings Per 1 Jug Will Last week Servings Servings Week (Weeks) 1 3 3 24 3.75 2 6 3 27 3.33 3 9 3 30 3.00 4 12 3 33 2.73 5 15 3 36 2.50 6 18 3 39 2.31 7 21 3 42 2.14 The Original Xtend Megadosing Experiment: http://forum.bodybuilding.com/showthread.php?t=431025&highlight=Megadose Cardiovascular Training Different scenarios: (1) Cardio only (2) Cadio AM, Weight training PM (or vise versa) (3) Weight training followed by cardio (4) HIIT Depending on the duration and intensity, cardiovascular exercise can deplete muscle glycogen levels significantly. Supplementing with Xtend will assist in sparing muscle glycogen and muscle tissue and increase gluconeogensis. In addition to this, the citrulline-malate in Xtend will increase your performance due to its ATP boosting effects. (1) Cardio only If you are only doing cardio on a given day, I would treat this just as you would a weight training workout. Start sipping your Xtend 15 minutes prior to the start of your cardio (i.e. while driving to the gym). Continue sipping Xtend throughout your cardio session. Dosing will depend mainly on the duration. I would suggest taking 1 serving of Xtend per 10 minutes of cardio. Cardio Duration Xtend (mins) Servings 10 1 20 2 30 3 40 4 50 5 60 6 Another option would be to decrease the amount of Xtend and add some whey protein for session greater than 40 minutes. For example, you could do 3 servings of Xtend and 1 serving of Substance WPI (with the matching flavor). (2) Cardio AM, Weight Training PM If you perform both cardio and weight training on the same day, I would recommend dosing 3 servings of Xtend pre/during/post weight training as outlined above and supplementing with an additional 2-3 servings of Xtend during your cardio session. (3) Weight training followed by cardio If you perform cardio after your weight training session, I would recommend increasing your Xtend servings from 3 to 4-6 servings. Add all of the servings to a jug or water bottle and sip throughout your weight training session as usual. Whatever Xtend you did not drink during your workout is to be drunk during your cardio session. (4) HIIT HIIT is an anaerobic form of cardio. While a HIIT session is usually shorter in duration then a cardiovascular session, it is much more intense. I would recommend using 1-3 servings of Xtend during the session. If you are doing sprints, I would suggest taking 1 scoop (1/2 servings) per 5 sprints. Number of Xtend Sprints Servings 5 0.5 10 1 15 1.5 20 2 25 2.5 30 3 What Supplements Can I Combine with Xtend for Enhanced Results? The Mammalian Target of Rapamycin (mTOR) is one of the body's protein synthesis regulators. mTOR functions as an energy sensor; it is activated when ATP levels are high and blocked when ATP levels are decreased (AMPK is activated when ATP decreases, which works antagonistically to mTOR). The main energy-consuming process in the cell is protein synthesis. When mTOR is activated (high ATP levels sensed) protein synthesis is increased and when mTOR is suppressed (low ATP levels are sensed) protein synthesis is blunted. MTOR activation is vital for skeletal muscle hypertrophy. Interestingly, mTOR is also a nutrient sensor of amino acid availability, specifically of leucine availability. Research has shown that regulation of mTOR by ATP and amino acids act independently through separate mechanisms (Dennis et al., 2001). It is my belief that combining supplements that increase/elevate ATP levels with BCAA will lead to an increased activation of mTOR, and therefore protein synthesis. Our goal is to keep ATP levels elevated while working out. To do so, we must supply the needed nutrients and substrates before and after the workout to keep ATP levels elevated and our bodies primed for growth. Creatine Creatine is used in the high-energy phosphate or ATP-PCr system to regenerate ATP. ATP, the body's main source of energy, is a molecule of adenosine (adenine + the sugar ribose) linked to three phosphate molecules by high-energy bonds. Breaking of the two outer bonds results in the release of energy. When the most outer bond is broken, the energy is released and ADP and Pi are left behind. Creatine, which is bonded to a phosphate ion, transfers energy to the ADP and Pi molecule by breaking its own bond. This regenerates the ATP molecule, which means one now has more energy to use. Skeletal muscle has a limited storage of creatine. Therefore supplementing with creatine increases your ability to form ATP and therefore increases the available energy for exercise (Casey et al. 1996 & 2000). More importantly to our topic on hand, by keeping ATP levels by supplementing with creatine we increase protein synthesis through mTOR activation. Creatine also has many other beneficial effects that are to numerous to address here. Nitric Oxide (NO) product (Arginine, DiArginine-Malate, AAKG, etc) The rate-limiting step of amino acid uptake into skeletal muscle is the transportation of the amino acids through the blood to the skeletal muscle, which is governed by blood flow (Wolfe, 2004). NO vasodilates blood vessels, thereby increasing blood flow. This increase when combined with exercises means greater blood flow and greater amino acid deliver and uptake in the working skeletal muscle. Exercise itself results in an increase in NO production, and the increased blood flow created by exercise is believed to be linked to the increase in protein synthesis post workout (Douglas et al., 2004). Xtend already has Citrulline-Malate in it, which will increase NO production, but an additional serving of arginine (i.e. 5 grams) preworkout should further enhance NO production, blood flow, and amino acid uptake. References: Casey, A, Constantin-Teodosiu D, Howell S, Hultman E, Greenhaff PL. (1996) Creatine ingestion favorably affects performance and muscle metabolism during maximal exercise in humans. Am J Physiol. Jul;271:E31-7. Casey A, Greenhaff PL. (2000).Does dietary creatine supplementation play a role in skeletal muscle metabolism and performance?Am J Clin Nutr. Aug;72(2 Suppl):607S17S. Review. Doi M, Yamaoka I, Fukunaga T, Nakayama M. Isoleucine, a potent plasma glucoselowering amino acid, stimulates glucose uptake in C2C12 myotubes. Biochem Biophys Res Commun. 2003 Dec 26;312(4):1111-7. Douglas, Borsheim, and Wolfe. "Potential Ergogenic Effects of Arginine and Creatine Supplementation" J Nutr. 2004 Oct;134(10 Suppl):2888S-2894S. Shimomura, Y. Murakami, T.Nakai, N. Nagasaki, M. Harri, R.A. (2004). Exercise Promotes BCAA Catabolism: Effects of BCAA Supplementation on Skeletal Muscle during Exercise J. Nutri. 134: 1583S-1587S. Taylor WM, Halperin ML. Effect of valine on the control of fatty acid synthesis in white adipose tissue of the rat. Can J Biochem. 1975 Oct;53(10):1054-60. Wolfe, et. al., In vivo muscle amino acid transport involves two distinct processes. Am J Physiol Endocrinol Metab. 2004 Jul;287(1):E136-41. Xtend Reviews By: Danny Wegg Hithard Objective: Muscle Gain Starting Weight: N/A Ending Weight: N/A Link to before Pic: http://forum.bodybuilding.com/attachment.php?attachmentid=284227&d=1141775220 Link to After: N/A Noticed a great deal of recovery with xtend, was never sore from workouts on most occasions. I wish I would have bought the bigger tub of xtend. Was defiantly worth buying, looking at my self I can't really tell if I'm bigger, but I believe I am. I'm more defined and recovery (although I don't care) is good. Scivation you guys are crack dealers in the supplement industry. You put out a good product (Xtend) and then make innocent people like me steal TVs and shit in order to buy more. After coming off Xtend I miss it, got to buy some more when I get the money. BiGToMCaT28 Objective: Muscle Gain Starting Weight: 240 BF 17% Ending Weight: N/A Link to before Pic: N/A Link to After: N/A Xtend is a great and proven product. I love Xtend; I can’t see myself lifting without it. The taste is great, if I had more money I'd drink it all day, everyday. I am increasing strength, and I have noticed an increase in endurance as well. y19mike77 Objective: Muscle Gain Starting Weight: 190 Ending Weight: N/A Link to before Pic: N/A Link to After: N/A Xtend taste good, has a little hint of medicine taste but you don’t taste it much after three sips. Started having vivid dreams, I think Xtend was raising my growth hormone levels. In two weeks I gained three pounds and my strength is up, my recovery has improved so much it doesn’t feel like I work out enough. My recovery time between sets is awesome; it’s hard to fully fatigue my muscles now. onionhead444 Objective: Muscle Gain Starting Weight: 191 13% BF Ending Weight: N/A Link to before Pic: N/A Link to After: N/A I think Xtend will become a staple in my supplement regimen. Having some of my best workouts since supplementing with Xtend. Strength is increasing nicely, Noticed an increase in recovery. Mivi320 Objective: Muscle Gain Starting Weight: 161 Ending Weight: 165 Link to before pic: http://forum.bodybuilding.com/showpost.php?p=8476943&postcount=817 Link to after: http://forum.bodybuilding.com/attachment.php?attachmentid=283966&d=1141694485 Sipping on Xtend during workouts has played a huge role in me setting PR in the gym. I love the taste of Xtend as well, it taste like watermelon Kool-Aid. Been noticing quicker recovery between sets as well. Xtend has greatly decreased doms, I barely having any doms since supplementing with Xtend. Definitely loving the mega dose of Xtend. I'm able to do cardio after my workouts for 15-20 mins while sipping Xtend, and still recover. Well, after finishing mega dosing with Xtend for almost 2 months, I am flattered with the results. Gains in LBM and a loss of body fat, simultaneously! I'm up to 165 pounds and body fat is at 11.8%. I'm looking leaner than ever and feel great! I've been training 6 days a week and doing cardio 4-5 times a week on top of that with no problems in terms of recovery! I set several PRs day in and day out of the weight room and felt energized and strong as ever while on Xtend! I plan on mega dosing with more Xtend come May when I do a recomp phase. As a matter of fact, I just ordered some more tubs of Xtend! I want to thank everyone at Scivation for making such great products. I will continue to purchase your products and support your company! colinballin23 Objective: Muscle Gain Starting Weight: 184-185 BF 14% Ending Weight: N/A Link to before Pic: http://forum.bodybuilding.com/attachment.php?attachmentid=222373&d=1122264120 Link to After: N/A Energy was up and felt zoned in; the taste was not bad either. I love the taste of grape Xtend. I've been really enjoying the Xtend the grape taste is good I could sip on it all day. My upper body is starting to look really good my pecs are getting good separation I've been having trouble building them but lately I've been making good progress. My energy levels and endurance are really up that is what I like most so far towards the end of my workouts I still feel like I got a lot left in the tank. Strength is going up a little on some lifts I'll go into more detail on that as time goes on but so far just seeing minimal progress in that area. The stamina I got at the gym was incredible I could workout for hours on this stuff. My energy levels were always way up I'd sweat a lot more than I normally do. These areas are really the 2 aspects I noticed increase in most. MA$$IVE Objective: Muscle Gain Starting Weight: 175 BF 9% Ending Weight: 182 Link to before Pic: N/A Link to After: N/A Noticed a nice increase in strength on almost all lifts the first week. Vasculiraty has been steadily increasing. I also like the taste of Xtend, it’s nice and pleasant. Xtend is absolutely helping with recovery and stamina. I am able to pump out more reps and feel like I am able to train the same muscle group again with in just a few days. Xtend is helping me a lot; I am stronger, faster, and endured after 6 days of use. Cxm Objective: N/A Starting Weight: N/A Ending Weight: N/A Link to before Pic: N/A Link to After: N/A Grape, in my opinion has a refreshing taste; I had to adjust the amount of water per serving. It's not too sweet, just right for me. The first time I tried it, I followed the directions regarding amount of water, and it had a lingering bitter aftertaste. The second time I added 1 serving to 24oz and it was great. I have taken the dosage of 3 servings (6 scoops) a day for a week (7 days). Recovery is noticeable and during workouts had an excellent amount of energy. In some workouts I noticed the increase in stamina, and managed more reps. I am pleased with the results from this product and considering making it a staple in my supplements. I highly recommend this product to others who are feeling lethargic during their workouts and feeling extremely sore after their workouts. Keep up the great work Scivation. TheDiesel Objective: N/A Starting Weight: N/A Ending Weight: N/A Link to before Pic: N/A Link to After: N/A The watermelon is the best tasting supplement regardless of what particular supplement you’re talking about. To get the most out of it, in my humble opinion, is to put about 5 scoops into 16 ounces of water in the morning on an empty stomach. I've been doing this for a few months and I've dropped percentages of fat whilst keeping or even gaining, more muscle to the effect of being ripped to hell. Watermelon Xtend is so good, in fact, that I occasionally mix it into a pre workout "NO" formula just to make it taste better. Hybrid Objective: N/A Starting Weight: 157 BF 9% Ending Weight: N/A Link to before Pic: N/A Link to After: N/A Notice a decrease in soreness and fatigue. I also love the taste of Xtend; it has really grown on me. It taste great sipping on it well swimming. I am really like Xtend, and I don’t think my recovery would be as good as it is without Xtend. The more Xtend I took the more I recovered. As for taste I could drink this all day, it reminds me of Kool-Aid. I highly recommend this product to people who are having trouble with recovering from their workouts. TheHAWG Objective: Muscle Gain Starting Weight: 161 BF 8-9% Ending Weight: N/A Link to before Pic: http://forum.bodybuilding.com/attachment.php?attachmentid=238573&d=1127777100 Link to After: N/A Saw nice strength gains immediately. Also have been throwing around more weight then usual and my soreness has decreased as well. Minddraper Objective: N/A Starting Weight: 172 BF 11-12% Ending Weight: N/A Link to before Pic: N/A Link to After: N/A When you get used to the taste of Xtend it really becomes an addiction. I personally believe Xtend helps a lot with recovery. Noticed an increase in strength and also in vasculiraty, I look more jacked since taking Xtend. Since taking Xtend have been setting PR all the time. Warriors Objective: Muscle Gain Starting Weight: 190-195 Ending Weight: N/A Link to before Pic: N/A Link to After: N/A After my first day of lifting chest/shoulders, I didn’t feel sore at all the next day. It felt like I never even worked out. I also like the taste of Xtend; Scivation is a good company that makes good products. Also noticed a nice increase in strength. Andyo Objective: N/A Starting Weight: N/A Ending Weight: N/A Link to before Pic: N/A Link to After: N/A Well the first two or three days I felt absolutely nothing and my recovery was somewhat slower than normal actually, energy levels were a bit up and down for a few as well. After about 4 days of regular dosing as suggested, I began to feel much better post-heavy training, my cardio was much better due to no crash afterwards, and actually felt less sore and much better the next day, even after leg day, which usually is a killer and am sore for 3 or 4 days post. I just felt stronger. So far it is doing what it says for me, and I like it. Two very enthusiastic thumbs up. Youngvet1 Objective: Fat Loss Starting Weight: 211 BF 10.5-11% Ending Weight: 207 Link to before Pic: N/A Link to After: N/A Noticed a nice increase in recovery, I was coming off creatine when I started this and thought I would be sore but I am not. My endurance has also greatly increased since taking Xtend, I used to use Ice but since going to Xtend ive noticed quite a bit of difference. I added some sets to my workouts because I was recovering so well, and I still recovered well from the increased volume. Bammy Objective: Fat Loss Starting Weight: 162 BF 7.8% Ending Weight: N/A Link to before Pic: N/A Link to After: N/A The taste of Xtend is great, after taking my first serving of Xtend I really craved it. Xtend makes me feel calm and happier, makes me feel like I satisfied a craving. Since taking Xtend I can handle much longer workouts, really helps with recovery and helps me from fatiguing. Xtend is letting me train more often then I used to able to train. Also making some nice strength gains in the gym. I've never had recovery this quick in my life. DOMS is decreased in length and intensity. Even though I train everyday, I feel I could train more than this and be fine. It was a great idea to combine bcaa's and CM for recovery. Xtend picks me up from fatigue in a snap. It definitely lessens the perceived effort of intensity techniques like drop sets, super sets, and forced reps. Also makes cardio more tolerable. Long workouts feel like short ones. Short workouts just feel too easy.