akn
Musclechemistry Member
Androgenic 30-40
Anabolic 100-150
Chemical Names 17beta-hydroxy-l alpha-methyl-Salpha-androstan-3-one
l-methyl-Salpha-dihydrotestosterone
Estrogenic Activity none
Progestational Activity not significant
Description:
Proviron® is Schering's brand name for the oral androgen
mesterolone (1-methyl dihydrotestosterone). Similar to
dihydrotestosterone, mesterolone is a strong androgen
with only a weak level of anabolic activity.This is due to the
fact that like dihydrotestosterone, mesterolone is rapidly
reduced to inactive diol metabolites in muscle tissue
where concentrations of the 3-hydroxysteroid
dehydrogenase enzyme are high. The belief that the weak
anabolic nature of this compound indicates a tendency to
block the androgen receptor in muscle tissue, thereby
reducing the gains of other more potent muscle-building
steroids, should likewise not be taken seriously. In fact, due
to its extremely high affinity for plasma binding proteins
such as SHBG, mesterolone may actually work to potentate
the activity of other steroids by displacing a higher
percentage into a free, unbound state. Among athletes,
mesterolone is primarily used to increase androgen levels
when dieting or preparing for a contest, and as an antiestrogen
due to its intrinsic ability to antagonize the
aromatase enzyme.
History:
According to company literature, Schering developed
Proviron® in 1934, making this is an extremely old
medication as far as anabolic/androgenic steroids.
Schering also states that it was the first medication put into
clinica.l practice for the treatment of "hormone-related
diseases and complaints in men."Accordingly, mesterolone
would have been developed around the same time as
methyltestosterone (1935) and testosterone propionate
(1937), which are both very old agents generally
considered obsolete by today's standards. In spite of its
age, Proviron has a long history of clinical effectiveness and
safety, and remains in widespread clinical use today. It is
generally prescribed to males for the treatment of
declining physical and mental capacity caused by age and
subnormal androgen levels, low libido caused by insufficient androgen levels, hypogonadism (in pre- and
post- pubescent males), and infertility (in certain situations
mesterolone increases the quality and quantity of sperm).
The use of mesterolone as a fertility aid is perhaps one of
the most controversial indications for this drug
considering that anabolic/androgenic steroids are
generally linked to infertility. It is also a use of mesterolone
that is quite often misunderstood by athletes. Mesterolone
is applicable here because it is an effective androgen that
offers minimal suppression of gonadotropins in normal
therapeutic doses, not because it increases LH output.
Absent gonadotropin suppression, the drug may
supplement androgenicity necessary for sperm
production. It is well understood that androgens have
direct stimulatory effects on spermatogenesis, and also
influence the transportation and maturation of sperm via
effects on the epididymis, ductus deferens, and seminal
vesicles. So the role of these hormones is not entirely
suppressive. Mesterolone seems to have a unique positive
influence on certain cases of male fertility because its
potential stimulatory effects on sperm quantity and quality
are not overridden by the suppression of gonadotropins.
Mesterolone is widely manufactured by Schering, which
currently sells the drug in more than thirty countries
worldwide.The most common brand name used for its sale
is Provi-ron, although Schering has sold the agent under
other names in certain markets, including Mestoranum
and Provironum. Additionally, other manufacturers have
sold mesterolone over the years, appearing under such
brand names as Pluriviron (Asche, Germany), Vistimon
(Jenepharm, Germany), and Restore (Brown & Burke, India).
In spite of its long track record of safety and efficacy,
mesterolone was never approved for sale in the United
States. It remains available in many Western nations,
however. Schering remains the major (almost exclusive)
global supplier of mesterolone today, although on rare
occasion other brands of the drug can be located .
How Supplied:
Mesterolone is widely available in human drug markets.
Composition and dosage may vary by country and
manufacturer; preparations generally contain 25 mg or 50
mg of steroid per tablet.
Structural Characteristics:
Mesterolone is a modified form of dihydrotestosterone. It
differs by the addition of a methyl group at carbon 1,
which helps protect the hormone from hepatic
metabolism during oral administration. The same
structural modification is also used with oral Primobolan®
(methenolone) tablets. Alkylation at the one position
slows hepatic metabolism of the steroid during the first
pass, although much less profoundly than c-17 alpha
alkylation. Mesterolone is resistant enough to breakdown
to allow therapeutically beneficial blood levels to be
achieved, although the overall bioavailability remains
much lower than c-17 alpha alkylated oral steroids.
Mesterolone also has a very strong binding affinity for Sex
Hormone Binding Globulin/1o This may act to displace
other steroids more weakly bound to SHBG into a free
(active) state.
Side Effects (Estrogenic):
Mesterolone is not aromatized by the body, and is not
measurably estrogenic. An anti-estrogen is not necessary
when using this steroid, as the drug is unlikely to induce
gynecomastia, water retention, or other estrogen-related
side effects.
Mesterolone is actually believed to act as an antiaromatase
in the body, preventing or slowing the
conversion of steroids into estrogen. The result is
somewhat comparable to Arimidex®, although less
profound. The anti-estrogenic properties of mesterolone
are not unique, and a number of other steroids have
demonstrated similar activity. Dihydrotestosterone and
Masteron (2-methyl-dihydrotestosterone), for example,
have been successfully used as therapies for
gynecomastia and breast cancer due to their strong
androgenic and potentially anti-estrogenic effect. It has
also been suggested that nandrolone may even lower
aromatase activity in peripheral tissues where it is more
resistant to estrogen conversion (the most active site of
nandrolone aromatization seems to be the liver).The antiestrogenic
effect of all of these compounds is presumably
caused by their ability to compete with other substrates
for binding to the aromatase enzyme. With the aromatase
enzyme bound to the steroid, yet being unable to alter it,
an inhibiting effect is achieved as it is temporarily blocked
from interacting with other hormones.
Side Effects (Androgenic):
Mesterolone is classified as an androgenic steroid.
Androgenic side effects are common with this substance,
especially with higher doses. This may include bouts of
oily skin, acne, and body/facial hair growth.
Anabolic/androgenic steroids may also aggravate male
pattern hair loss. Women are also warned of the potential
virilizing effects of anabolic/androgenic steroids. These
may include a deepening of the voice, menstrual
irregularities, changes in skin texture, facial hair growth,
and clitoral enlargement. Additionally, the 5-alpha
reductase enzyme does not metabolize mesterolone, so
its relative androgenicity is not affected by finasteride or
dutasteride.
Side Effects (Hepatotoxicity):
Mesterolone is not c17-alpha alkylated, and not known to
produce hepatotoxic effects; liver toxicity is unlikely.
Side Effects (Cardiovascular):
Anabolic/androgenic steroids can have deleterious effects
on serum cholesterol. This includes a tendency to reduce
HDL (good) cholesterol values and increase LDL (bad)
cholesterol values, which may shift the HDL to LDL
balance in a direction that favors greater risk of
arteriosclerosis. The relative impact of an
anabolic/androgenic steroid on serum lipids is dependant
on the dose, route of administration (oral vs. injectable),
type of steroid (aromatizable or non-aromatizable), and
level of resistance to hepatic metabolism. Mesterolone is
an oral non-aromatizable androgen,and expected to have
a notable negative effect on lipids. Studies administering
100 mg of mesterolone per day to hypogonadal men for
approximately 6 months demonstrated a significant
increase in total cholesterol (18.80/0) and LDL cholesterol
(65.20/0), accompanied by a significant decrease in HDL
cholesterol (-35.7°;6).111
Mesterolone should not be used when cardiovascular risk
factors preclude the use of other oral steroids.
To help reduce cardiovascular strain it is advised to
maintain an active cardiovascular exercise program and
minimize the intake of saturated fats, cholesterol, and
simple carbohydrates at all times during active AAS
administration. Supplementing with fish oils (4 grams per
day) and a natural cholesterol/antioxidant formula such as
Lipid Stabil or a product with comparable ingredients is
also recommended.
Side Effects (Testosterone Suppression):
Mesterolone has a very weak suppressive effect on
gonadotropins and serum testosterone. Studies show that
when given in moderate doses (150 mg per day or less), significant suppression of testosterone levels does not
occur'?' 2 In studies with higher doses (300 mg per day and
above), the agent strongly suppressed serum
testosterone.?' 3
The above side effects are not inclusive. For more detailed
discussion ofpotential side effects, see the Steroid Side Effects
section of this book.
Administration (Men):
To treat androgen insufficiency, mesterolone is usually
given in a dose of 1 tablet (25 mg) three times per day at
the initiation of therapy. The drug is later continued at a
lower maintenance dose, which usually consists of taking
1 tablet (25 mg) one to two times per day. Similar doses
are used to support male fertility, usually in conjunction
with other fertility drugs like injectable FSH. The usual
dosage among male athletes is between 50 mg and 150
mg of mesterolone per day, or two to six 25 mg tablets.
The drug is typically taken in cycles of 6-12 weeks in
length, which is usually a sufficient period of time to
notice the benefits of drug therapy.
Many bodybuilders favor the use of mesterolone during
dieting phases or contest preparation, when low estrogen
and high androgen levels are particularly desirable. This is
especially beneficial when anabolics like Winstrol®,
Anavar, or Primobolan® are being used alone, as the
androgenic content of these drugs is relatively low.
Mesterolone can be effectively used here to adjust the
androgen to estrogen ratio upwards, bringing about an
increase in the hardness and density of the muscles,
supporting libido and general sense of well being, and
increasing the tendency to burn body fat. It is also
commonly used (at a similar dosage) to prevent
gynecomastia when other aromatizable steroids are
being administered, often in conjunction with 10-20 mg
per day of Nolvadex.
Administration (Women):
Mesterolone is not approved for use in women.This agent
is not recommended for women for physique- or
performance-enhancing purposes due to its strong
androgenic nature and tendency to produce virilizing side
effects. Some women do favor the drug, however, and find
a single 25 mg tablet enough to efficiently shift the
hormone balance in the body, greatly impacting the look
of definition to the physique. Intake is usually limited to no
longer than four or five weeks in such situations to
minimize the chance of developing lasting virilizing
effects. One tablet used in conjunction with 10 or 20 mg of
Nolvadex® can be even more efficient for muscle
hardening, creating an environment where the body is
much more inclined to burn off extra body fat, especially in female trouble areas like the hips and thighs. Extreme
caution should be taken with such use, however.
Availability:
Most versions of mesterolone are manufactured by, or
under license from, Schering. These are packaged in both
push-through strips and small glass vials, depending on
the market. Counterfeits are not currently known to be a
problem.
Anabolic 100-150
Chemical Names 17beta-hydroxy-l alpha-methyl-Salpha-androstan-3-one
l-methyl-Salpha-dihydrotestosterone
Estrogenic Activity none
Progestational Activity not significant
Description:
Proviron® is Schering's brand name for the oral androgen
mesterolone (1-methyl dihydrotestosterone). Similar to
dihydrotestosterone, mesterolone is a strong androgen
with only a weak level of anabolic activity.This is due to the
fact that like dihydrotestosterone, mesterolone is rapidly
reduced to inactive diol metabolites in muscle tissue
where concentrations of the 3-hydroxysteroid
dehydrogenase enzyme are high. The belief that the weak
anabolic nature of this compound indicates a tendency to
block the androgen receptor in muscle tissue, thereby
reducing the gains of other more potent muscle-building
steroids, should likewise not be taken seriously. In fact, due
to its extremely high affinity for plasma binding proteins
such as SHBG, mesterolone may actually work to potentate
the activity of other steroids by displacing a higher
percentage into a free, unbound state. Among athletes,
mesterolone is primarily used to increase androgen levels
when dieting or preparing for a contest, and as an antiestrogen
due to its intrinsic ability to antagonize the
aromatase enzyme.
History:
According to company literature, Schering developed
Proviron® in 1934, making this is an extremely old
medication as far as anabolic/androgenic steroids.
Schering also states that it was the first medication put into
clinica.l practice for the treatment of "hormone-related
diseases and complaints in men."Accordingly, mesterolone
would have been developed around the same time as
methyltestosterone (1935) and testosterone propionate
(1937), which are both very old agents generally
considered obsolete by today's standards. In spite of its
age, Proviron has a long history of clinical effectiveness and
safety, and remains in widespread clinical use today. It is
generally prescribed to males for the treatment of
declining physical and mental capacity caused by age and
subnormal androgen levels, low libido caused by insufficient androgen levels, hypogonadism (in pre- and
post- pubescent males), and infertility (in certain situations
mesterolone increases the quality and quantity of sperm).
The use of mesterolone as a fertility aid is perhaps one of
the most controversial indications for this drug
considering that anabolic/androgenic steroids are
generally linked to infertility. It is also a use of mesterolone
that is quite often misunderstood by athletes. Mesterolone
is applicable here because it is an effective androgen that
offers minimal suppression of gonadotropins in normal
therapeutic doses, not because it increases LH output.
Absent gonadotropin suppression, the drug may
supplement androgenicity necessary for sperm
production. It is well understood that androgens have
direct stimulatory effects on spermatogenesis, and also
influence the transportation and maturation of sperm via
effects on the epididymis, ductus deferens, and seminal
vesicles. So the role of these hormones is not entirely
suppressive. Mesterolone seems to have a unique positive
influence on certain cases of male fertility because its
potential stimulatory effects on sperm quantity and quality
are not overridden by the suppression of gonadotropins.
Mesterolone is widely manufactured by Schering, which
currently sells the drug in more than thirty countries
worldwide.The most common brand name used for its sale
is Provi-ron, although Schering has sold the agent under
other names in certain markets, including Mestoranum
and Provironum. Additionally, other manufacturers have
sold mesterolone over the years, appearing under such
brand names as Pluriviron (Asche, Germany), Vistimon
(Jenepharm, Germany), and Restore (Brown & Burke, India).
In spite of its long track record of safety and efficacy,
mesterolone was never approved for sale in the United
States. It remains available in many Western nations,
however. Schering remains the major (almost exclusive)
global supplier of mesterolone today, although on rare
occasion other brands of the drug can be located .
How Supplied:
Mesterolone is widely available in human drug markets.
Composition and dosage may vary by country and
manufacturer; preparations generally contain 25 mg or 50
mg of steroid per tablet.
Structural Characteristics:
Mesterolone is a modified form of dihydrotestosterone. It
differs by the addition of a methyl group at carbon 1,
which helps protect the hormone from hepatic
metabolism during oral administration. The same
structural modification is also used with oral Primobolan®
(methenolone) tablets. Alkylation at the one position
slows hepatic metabolism of the steroid during the first
pass, although much less profoundly than c-17 alpha
alkylation. Mesterolone is resistant enough to breakdown
to allow therapeutically beneficial blood levels to be
achieved, although the overall bioavailability remains
much lower than c-17 alpha alkylated oral steroids.
Mesterolone also has a very strong binding affinity for Sex
Hormone Binding Globulin/1o This may act to displace
other steroids more weakly bound to SHBG into a free
(active) state.
Side Effects (Estrogenic):
Mesterolone is not aromatized by the body, and is not
measurably estrogenic. An anti-estrogen is not necessary
when using this steroid, as the drug is unlikely to induce
gynecomastia, water retention, or other estrogen-related
side effects.
Mesterolone is actually believed to act as an antiaromatase
in the body, preventing or slowing the
conversion of steroids into estrogen. The result is
somewhat comparable to Arimidex®, although less
profound. The anti-estrogenic properties of mesterolone
are not unique, and a number of other steroids have
demonstrated similar activity. Dihydrotestosterone and
Masteron (2-methyl-dihydrotestosterone), for example,
have been successfully used as therapies for
gynecomastia and breast cancer due to their strong
androgenic and potentially anti-estrogenic effect. It has
also been suggested that nandrolone may even lower
aromatase activity in peripheral tissues where it is more
resistant to estrogen conversion (the most active site of
nandrolone aromatization seems to be the liver).The antiestrogenic
effect of all of these compounds is presumably
caused by their ability to compete with other substrates
for binding to the aromatase enzyme. With the aromatase
enzyme bound to the steroid, yet being unable to alter it,
an inhibiting effect is achieved as it is temporarily blocked
from interacting with other hormones.
Side Effects (Androgenic):
Mesterolone is classified as an androgenic steroid.
Androgenic side effects are common with this substance,
especially with higher doses. This may include bouts of
oily skin, acne, and body/facial hair growth.
Anabolic/androgenic steroids may also aggravate male
pattern hair loss. Women are also warned of the potential
virilizing effects of anabolic/androgenic steroids. These
may include a deepening of the voice, menstrual
irregularities, changes in skin texture, facial hair growth,
and clitoral enlargement. Additionally, the 5-alpha
reductase enzyme does not metabolize mesterolone, so
its relative androgenicity is not affected by finasteride or
dutasteride.
Side Effects (Hepatotoxicity):
Mesterolone is not c17-alpha alkylated, and not known to
produce hepatotoxic effects; liver toxicity is unlikely.
Side Effects (Cardiovascular):
Anabolic/androgenic steroids can have deleterious effects
on serum cholesterol. This includes a tendency to reduce
HDL (good) cholesterol values and increase LDL (bad)
cholesterol values, which may shift the HDL to LDL
balance in a direction that favors greater risk of
arteriosclerosis. The relative impact of an
anabolic/androgenic steroid on serum lipids is dependant
on the dose, route of administration (oral vs. injectable),
type of steroid (aromatizable or non-aromatizable), and
level of resistance to hepatic metabolism. Mesterolone is
an oral non-aromatizable androgen,and expected to have
a notable negative effect on lipids. Studies administering
100 mg of mesterolone per day to hypogonadal men for
approximately 6 months demonstrated a significant
increase in total cholesterol (18.80/0) and LDL cholesterol
(65.20/0), accompanied by a significant decrease in HDL
cholesterol (-35.7°;6).111
Mesterolone should not be used when cardiovascular risk
factors preclude the use of other oral steroids.
To help reduce cardiovascular strain it is advised to
maintain an active cardiovascular exercise program and
minimize the intake of saturated fats, cholesterol, and
simple carbohydrates at all times during active AAS
administration. Supplementing with fish oils (4 grams per
day) and a natural cholesterol/antioxidant formula such as
Lipid Stabil or a product with comparable ingredients is
also recommended.
Side Effects (Testosterone Suppression):
Mesterolone has a very weak suppressive effect on
gonadotropins and serum testosterone. Studies show that
when given in moderate doses (150 mg per day or less), significant suppression of testosterone levels does not
occur'?' 2 In studies with higher doses (300 mg per day and
above), the agent strongly suppressed serum
testosterone.?' 3
The above side effects are not inclusive. For more detailed
discussion ofpotential side effects, see the Steroid Side Effects
section of this book.
Administration (Men):
To treat androgen insufficiency, mesterolone is usually
given in a dose of 1 tablet (25 mg) three times per day at
the initiation of therapy. The drug is later continued at a
lower maintenance dose, which usually consists of taking
1 tablet (25 mg) one to two times per day. Similar doses
are used to support male fertility, usually in conjunction
with other fertility drugs like injectable FSH. The usual
dosage among male athletes is between 50 mg and 150
mg of mesterolone per day, or two to six 25 mg tablets.
The drug is typically taken in cycles of 6-12 weeks in
length, which is usually a sufficient period of time to
notice the benefits of drug therapy.
Many bodybuilders favor the use of mesterolone during
dieting phases or contest preparation, when low estrogen
and high androgen levels are particularly desirable. This is
especially beneficial when anabolics like Winstrol®,
Anavar, or Primobolan® are being used alone, as the
androgenic content of these drugs is relatively low.
Mesterolone can be effectively used here to adjust the
androgen to estrogen ratio upwards, bringing about an
increase in the hardness and density of the muscles,
supporting libido and general sense of well being, and
increasing the tendency to burn body fat. It is also
commonly used (at a similar dosage) to prevent
gynecomastia when other aromatizable steroids are
being administered, often in conjunction with 10-20 mg
per day of Nolvadex.
Administration (Women):
Mesterolone is not approved for use in women.This agent
is not recommended for women for physique- or
performance-enhancing purposes due to its strong
androgenic nature and tendency to produce virilizing side
effects. Some women do favor the drug, however, and find
a single 25 mg tablet enough to efficiently shift the
hormone balance in the body, greatly impacting the look
of definition to the physique. Intake is usually limited to no
longer than four or five weeks in such situations to
minimize the chance of developing lasting virilizing
effects. One tablet used in conjunction with 10 or 20 mg of
Nolvadex® can be even more efficient for muscle
hardening, creating an environment where the body is
much more inclined to burn off extra body fat, especially in female trouble areas like the hips and thighs. Extreme
caution should be taken with such use, however.
Availability:
Most versions of mesterolone are manufactured by, or
under license from, Schering. These are packaged in both
push-through strips and small glass vials, depending on
the market. Counterfeits are not currently known to be a
problem.
