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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.
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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.