July 2019 musculardevelopment.com MD 67after consuming clenbuterol for 21 days. These
results show that myostatin function is induced
by clenbuterol where it functions as a negative
regulator in the later stages of clenbuterol use,
whereas IGF1 works as a positive regulator in
the earlier stages.
Creatine and Vitamin d
deCrease myostatin and
enhanCe Clenbuterol
Certain nutritional supplements are known
to inhibit myostatin. Therefore, consuming
them should negate myostatin’s hold on
muscle growth directly induced by clenbuterol.
Creatine is a well-characterized compound
that has been unmistakably shown to
enhance muscle size and strength. In addition
to creatine’s obvious function as a primary
energy storage molecule used to regenerate
muscle ATP, thus prolonging muscle function,
creatine has also been shown to stimulate
muscle growth.^4 More recently, however, a
study by Saremi et al.^5 demonstrated that
creatine consumption causes a decrease in
myostatin levels in muscle cells, leading to
significant muscle growth. In this study, two
groups of men performed resistance training
with or without creatine for a total of eight
weeks. Both groups showed decreased levels
of myostatin, but the group that performed
resistance training and consumed creatine had
a considerably larger decrease in myostatin
levels along with greater gains in muscle mass
and strength— clearly demonstrating the
ability of creatine to reduce myostatin levels,
improving muscle growth and strength.
Another potent myostatin inhibitor is
vitamin D. As shown in a study by Garcia et
al.^6 , vitamin D exposure decreased the amount
of myostatin found in isolated muscle cells,
generating greater muscle growth. In addition
to the decrease in myostatin, this study also
showed that vitamin D triggers an increase in
the powerful inhibitor of myostatin known as
follistatin, which increases muscle mass by
inhibiting myostatin.^7 Ultimately, this study
indicates that the decrease in myostatin level
and activity caused by vitamin D significantly
increased muscle fiber size.
essential amino aCids driVe
musCle Growth by reduCinG
myostatin
While essential amino acids (EAAs) have
been shown to potently activate mTOR-
stimulated muscle protein synthesis, leading
to greater muscle size8,9, another study by
Drummond et al.^10 demonstrated that EAAs
also have the uniquely powerful ability to
decrease genetic expression of myostatin in
muscle cells. EAAs decrease myostatin levels
by stimulating the production of a class of
molecules known as micro-RNA that have the
ability to strongly decrease the expression
level of specific genes. The unique finding
in this study was that several micro-RNA
molecules were produced in human skeletal
muscle following the ingestion of 10 grams
of EAAs, which subsequently decreased
myostatin expression by approximately 50
percent. Although further work is needed to
elucidate the precise role that micro-RNA has
in the regulation of myostatin and muscle
mass following EAA consumption, this
investigation represents a completely novel
way to decrease myostatin levels for enhanced
muscle growth.Clenbuterol Cuts
both ways
In summary, although clenbuterol has the
extraordinary capability to stimulate fat loss
while supporting muscle growth, clenbuterol
directly increases myostatin levels— which
may drive substantial muscle loss. On the
other hand, myostatin is such an extremely
responsive target that even a minor reduction
of clenbuterol-increased myostatin levels
should restore clenbuterol activity, boosting
notable muscle growth and fat loss. As
a result, clenbuterol’s ability to increase
myostatin function should be mitigated by
simultaneously consuming clenbuterol with
the right nutritional supplements that inhibit
myostatin and restore clenbuterol function that
only cuts fat and not muscle growth.References:- Kim KH, Kim YS and Yang J. The muscle-hypertrophic
effect of clenbuterol is additive to the hypertrophic effect of
myostatin suppression. Muscle Nerve 2011;43(5): p. 700-7. - Carter WJ, et al. Effects of clenbuterol on skeletal
muscle mass, body composition, and recovery from surgical
stress in senescent rats. Metabolism 1991;40(8): p. 855-60. - Abo T, et al. IGF and myostatin pathways are
respectively induced during the earlier and the later stages of
skeletal muscle hypertrophy induced by clenbuterol, a beta(2)
-adrenergic agonist. Cell Biochem Funct 2012;30(8): p. 671-6. - Willoughby DS and Rosene J. Effects of oral creatine
and resistance training on myosin heavy chain expression.
Med Sci Sports Exerc 2001;33(10): p. 1674-81. - Saremi A, et al. Effects of oral creatine and resistance
training on serum myostatin and GASP-1. Mol Cell Endocrinol
2009;317(1-2): p. 25-30. - Garcia LA, et al. 1,25(OH)2vitamin D3 stimulates
myogenic differentiation by inhibiting cell proliferation and
modulating the expression of promyogenic growth factors
and myostatin in C2C12 skeletal muscle cells. Endocrinology
2011;152(8): p. 2976-86. - Cash JN, et al. Structure of myostatin•follistatin-like
3: N-terminal domains of follistatin-type molecules exhibit
alternate modes of binding. J Biol Chem 2012;287(2): p. 1043-
- Fujita S, et al. Nutrient signalling in the regulation of
human muscle protein synthesis. J Physiol 2007;582(Pt 2):
p. 813-23. - Drummond MJ and Rasmussen BB. Leucine-enriched
nutrients and the regulation of mammalian target of
rapamycin signalling and human skeletal muscle protein
synthesis. Curr Opin Clin Nutr Metab Care 2008;11(3): p. 222-6. - Drummond MJ, et al. Essential amino acids increase
microRNA-499, -208b, and -23a and downregulate myostatin
and myocyte enhancer factor 2C mRNA expression in human
skeletal muscle. J Nutr 2009;139(12): p. 2279-84.