akn
Musclechemistry Member
Description:
Nandrolone phenylpropionate is an injectable form of the anabolic steroid nandrolone. The
properties of this drug are strikingly similar to those of Deca-Durabolin®, which uses the
slower acting drug nandrolone decanoate. The primary difference between these two
preparations is the speed in which nandrolone is released into the blood. While nandrolone
decanoate provides a release of nandrolone from the area of injection lasting approximately 3
weeks, nandrolone phenylpropionate is active for only about a week. In clinical situations,
Deca-Durabolin can thus be injected once every 2 or 3 weeks, while Durabolin® is usually
administered every several days to once weekly. Otherwise, the two drugs are virtually
interchangeable. Like Deca-Durabolin, Durabolin is valued by athletes and bodybuilders for
its abilities to promote strength and lean muscle mass gains without significant estrogenic or
androgenic side effects.
History:
Nandrolone phenylpropionate was first described in 1957.471 It became a prescription
medication shortly after, sold by the international pharmaceuticals giant Organon (now
Merck/MSD) under the brand name Durabolin. When first introduced to the United States,
indicated uses of nandrolone phenylpropionate included pre- and postoperative lean mass
retention, osteoporosis, advanced breast cancer, weight loss due to convalescence or
disease, geriatric states (general weakness and frailty), burns, severe trauma, ulcers, adjunct
therapy with certain forms of anemia, and selective cases of growth and development
retardation in children. During the 1970’s, the FDA began revising the indicated uses of this
drug, however, and they were soon significantly narrowed. Moving forward, the drug was
mainly being indicated for the treatment of advanced metastatic breast cancer, and as adjunct
therapy for the treatment of senile and post-menopausal osteoporosis.
Durabolin was a key focus of Organon’s marketing efforts only for well less than a decade
following its release. Once Deca-Durabolin was introduced during the 1960’s, this shorteracting
counterpart, although still available, started to take a back seat. Durabolin was not
completely abandoned by Organon at the time, however, partly due to the fact that it was
given a slightly different set of therapeutic uses in certain countries, and therefore continued to
hold onto a niche market for some time. As the size of the anabolic steroid market continued
to grow throughout the 1970’s and ’80’s, it was nandrolone decanoate that was attracting
the most attention of other drug manufacturers. Numerous drug companies had produced
their own versions of nandrolone phenylpropionate over the years, however. Today, the drug
remains scarcely available. It is unknown if the present owner of Organon (Merck/MSD) will
market Durabolin, or if its production (as a brand name product) has ended.
How Supplied:
Nandrolone phenylpropionate is available in select human drug markets. Composition and
dosage may vary by country and manufacturer, but usually contain 25 mg/mL or 50 mg/mL
of steroid dissolved in oil.
Structural Characteristics:
Nandrolone phenylpropionate is a modified form of nandrolone, where a carboxylic acid
ester (propionic phenyl ester) has been attached to the 17-beta hydroxyl group. Esterified
steroids are less polar than free steroids, and are absorbed more slowly from the area of
injection. Once in the bloodstream, the ester is removed to yield free (active) nandrolone.
Esterified steroids are designed to prolong the window of therapeutic effect following
administration, allowing for a less frequent injection schedule compared to injections of free
(unesterified) steroid. Nandrolone phenylpropionate provides a sharp spike in nandrolone
release 24-48 hours following deep intramuscular injection, and declines to near baseline
levels within a week.
Side Effects (Estrogenic):
Nandrolone has a low tendency for estrogen conversion, estimated to be only about 20% of
that seen with testosterone.472 This is because while the liver can convert nandrolone to
estradiol, in other more active sites of steroid aromatization such as adipose tissue
nandrolone is far less open to this process.473 Consequently, estrogen- related side effects
are a much lower concern with this drug than with testosterone. Elevated estrogen levels may
still be noticed with higher dosing, however, and may cause side effects such as increased
water retention, body fat gain, and gynecomastia. An anti-estrogen such as clomiphene
citrate or tamoxifen citrate may be necessary to prevent estrogenic side effects if they occur.
One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which more
efficiently controls estrogen by preventing its synthesis. Aromatase inhibitors can be quite
expensive in comparison to anti-estrogens, however, and may also have negative effects on
blood lipids.
It is of note that nandrolone has some activity as a progestin in the body.474 Although
progesterone is a c-19 steroid, removal of this group as in 19-norprogesterone creates a
hormone with greater binding affinity for its corresponding receptor. Sharing this trait, many
19-nor anabolic steroids are shown to have some affinity for the progesterone receptor as well.475 The side effects associated with progesterone are similar to those of estrogen,
including negative feedback inhibition of testosterone production and enhanced rate of fat
storage. Progestins also augment the stimulatory effect of estrogens on mammary tissue
growth. There appears to be a strong synergy between these two hormones here, such that
gynecomastia might even occur with the help of progestins, without excessive estrogen levels.
The use of an anti-estrogen, which inhibits the estrogenic component of this disorder, is often
sufficient to mitigate gynecomastia caused by nandrolone.
Side Effects (Androgenic):
Although classified as an anabolic steroid, androgenic side effects are still possible 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 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. Nandrolone is a steroid with relatively low
androgenic activity relative to its tissue-building actions, making the threshold for strong
androgenic side effects comparably higher than with more androgenic agents such as
testosterone, methandrostenolone, or fluoxymesterone. It is also important to point out that
due to its mild androgenic nature and ability to suppress endogenous testosterone,
nandrolone is prone to interfering with libido in males when used without another androgen.
Note that in androgen-responsive target tissues such as the skin, scalp, and prostate, the
relative androgenicity of nandrolone is reduced by its reduction to dihydronandrolone
(DHN).476 477
The 5-alpha reductase enzyme is responsible for this metabolism of nandrolone. The
concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride will interfere
with site-specific reduction of nandrolone action, considerably increasing the tendency of
nandrolone to produce androgenic side effects. Reductase inhibitors should be avoided with
nandrolone if low androgenicity is desired.
Side Effects (Hepatotoxicity):
Nandrolone is not c-17 alpha alkylated, and not known to have 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. Studies
administering 600 mg of nandrolone decanoate per week for 10 weeks demonstrated a 26%
reduction in HDL cholesterol levels.478 This suppression is slightly greater than that reported
with an equal dose of testosterone enanthate, and is in agreement with earlier studies showing
a slightly stronger negative impact on HDL/LDL ratio with nandrolone decanoate as
compared to testosterone cypionate.479 Nandrolone should still have a significantly weaker
impact on serum lipids than c-17 alpha alkylated agents. Anabolic/androgenic steroids may
also adversely effect blood pressure and triglycerides, reduce endothelial relaxation, and
support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular
disease and myocardial infarction.
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):
All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are
expected to suppress endogenous testosterone production. Studies administering 100 mg
injection of nandrolone phenylpropionate demonstrated a rapid suppression of serum
testosterone following a single injection. Testosterone levels declined to approximately 30%
of initial level by day 3 after drug administration, and stayed suppressed for approximately 13
days. Regular use is expected to significantly lengthen the endogenous hormone recovery
window. It is believed that the progestational activity of nandrolone notably contributes to the
suppression of testosterone synthesis during therapy, which can be marked in spite of a low
tendency for estrogen conversion.480 Without the intervention of testosterone-stimulating
substances, testosterone levels should return to normal within 2-6 months of drug secession.
Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid
abuse, necessitating medical intervention.
Administration (Men):
For general anabolic effects, early prescribing guidelines recommend a dosage of 25-50 mg
per week for 12 weeks. The usual dosage for physique- or performance-enhancing purposes
is in the range of 200-400 mg per week, taken in cycles 8 to 12 weeks in length. This level is
sufficient for most users to notice measurable gains in lean muscle mass and strength. Note
that due to the fastacting nature of the phenylpropionate ester, the weekly dosage is usually
subdivided into 2 separate applications spaced evenly apart.
Administration (Women):
For general anabolic effects, early prescribing guidelines recommend a dosage of 25-50 mg
per week for 12 weeks. When used for physique- or performance-enhancing purposes, a
dosage of 50 mg per week (given in a single weekly injection) is most common, taken for
cycle lasting 4 to 6 weeks. Higher doses or longer durations of use are discouraged due to
potential for androgenic side effects. Although only slightly androgenic, women are
occasionally confronted with virilization symptoms when taking this compound. Should
virilizing side effects become a concern, nandrolone phenylpropionate should be discontinued
immediately to help prevent a permanent appearance.
Nandrolone phenylpropionate is an injectable form of the anabolic steroid nandrolone. The
properties of this drug are strikingly similar to those of Deca-Durabolin®, which uses the
slower acting drug nandrolone decanoate. The primary difference between these two
preparations is the speed in which nandrolone is released into the blood. While nandrolone
decanoate provides a release of nandrolone from the area of injection lasting approximately 3
weeks, nandrolone phenylpropionate is active for only about a week. In clinical situations,
Deca-Durabolin can thus be injected once every 2 or 3 weeks, while Durabolin® is usually
administered every several days to once weekly. Otherwise, the two drugs are virtually
interchangeable. Like Deca-Durabolin, Durabolin is valued by athletes and bodybuilders for
its abilities to promote strength and lean muscle mass gains without significant estrogenic or
androgenic side effects.
History:
Nandrolone phenylpropionate was first described in 1957.471 It became a prescription
medication shortly after, sold by the international pharmaceuticals giant Organon (now
Merck/MSD) under the brand name Durabolin. When first introduced to the United States,
indicated uses of nandrolone phenylpropionate included pre- and postoperative lean mass
retention, osteoporosis, advanced breast cancer, weight loss due to convalescence or
disease, geriatric states (general weakness and frailty), burns, severe trauma, ulcers, adjunct
therapy with certain forms of anemia, and selective cases of growth and development
retardation in children. During the 1970’s, the FDA began revising the indicated uses of this
drug, however, and they were soon significantly narrowed. Moving forward, the drug was
mainly being indicated for the treatment of advanced metastatic breast cancer, and as adjunct
therapy for the treatment of senile and post-menopausal osteoporosis.
Durabolin was a key focus of Organon’s marketing efforts only for well less than a decade
following its release. Once Deca-Durabolin was introduced during the 1960’s, this shorteracting
counterpart, although still available, started to take a back seat. Durabolin was not
completely abandoned by Organon at the time, however, partly due to the fact that it was
given a slightly different set of therapeutic uses in certain countries, and therefore continued to
hold onto a niche market for some time. As the size of the anabolic steroid market continued
to grow throughout the 1970’s and ’80’s, it was nandrolone decanoate that was attracting
the most attention of other drug manufacturers. Numerous drug companies had produced
their own versions of nandrolone phenylpropionate over the years, however. Today, the drug
remains scarcely available. It is unknown if the present owner of Organon (Merck/MSD) will
market Durabolin, or if its production (as a brand name product) has ended.
How Supplied:
Nandrolone phenylpropionate is available in select human drug markets. Composition and
dosage may vary by country and manufacturer, but usually contain 25 mg/mL or 50 mg/mL
of steroid dissolved in oil.
Structural Characteristics:
Nandrolone phenylpropionate is a modified form of nandrolone, where a carboxylic acid
ester (propionic phenyl ester) has been attached to the 17-beta hydroxyl group. Esterified
steroids are less polar than free steroids, and are absorbed more slowly from the area of
injection. Once in the bloodstream, the ester is removed to yield free (active) nandrolone.
Esterified steroids are designed to prolong the window of therapeutic effect following
administration, allowing for a less frequent injection schedule compared to injections of free
(unesterified) steroid. Nandrolone phenylpropionate provides a sharp spike in nandrolone
release 24-48 hours following deep intramuscular injection, and declines to near baseline
levels within a week.
Side Effects (Estrogenic):
Nandrolone has a low tendency for estrogen conversion, estimated to be only about 20% of
that seen with testosterone.472 This is because while the liver can convert nandrolone to
estradiol, in other more active sites of steroid aromatization such as adipose tissue
nandrolone is far less open to this process.473 Consequently, estrogen- related side effects
are a much lower concern with this drug than with testosterone. Elevated estrogen levels may
still be noticed with higher dosing, however, and may cause side effects such as increased
water retention, body fat gain, and gynecomastia. An anti-estrogen such as clomiphene
citrate or tamoxifen citrate may be necessary to prevent estrogenic side effects if they occur.
One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which more
efficiently controls estrogen by preventing its synthesis. Aromatase inhibitors can be quite
expensive in comparison to anti-estrogens, however, and may also have negative effects on
blood lipids.
It is of note that nandrolone has some activity as a progestin in the body.474 Although
progesterone is a c-19 steroid, removal of this group as in 19-norprogesterone creates a
hormone with greater binding affinity for its corresponding receptor. Sharing this trait, many
19-nor anabolic steroids are shown to have some affinity for the progesterone receptor as well.475 The side effects associated with progesterone are similar to those of estrogen,
including negative feedback inhibition of testosterone production and enhanced rate of fat
storage. Progestins also augment the stimulatory effect of estrogens on mammary tissue
growth. There appears to be a strong synergy between these two hormones here, such that
gynecomastia might even occur with the help of progestins, without excessive estrogen levels.
The use of an anti-estrogen, which inhibits the estrogenic component of this disorder, is often
sufficient to mitigate gynecomastia caused by nandrolone.
Side Effects (Androgenic):
Although classified as an anabolic steroid, androgenic side effects are still possible 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 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. Nandrolone is a steroid with relatively low
androgenic activity relative to its tissue-building actions, making the threshold for strong
androgenic side effects comparably higher than with more androgenic agents such as
testosterone, methandrostenolone, or fluoxymesterone. It is also important to point out that
due to its mild androgenic nature and ability to suppress endogenous testosterone,
nandrolone is prone to interfering with libido in males when used without another androgen.
Note that in androgen-responsive target tissues such as the skin, scalp, and prostate, the
relative androgenicity of nandrolone is reduced by its reduction to dihydronandrolone
(DHN).476 477
The 5-alpha reductase enzyme is responsible for this metabolism of nandrolone. The
concurrent use of a 5-alpha reductase inhibitor such as finasteride or dutasteride will interfere
with site-specific reduction of nandrolone action, considerably increasing the tendency of
nandrolone to produce androgenic side effects. Reductase inhibitors should be avoided with
nandrolone if low androgenicity is desired.
Side Effects (Hepatotoxicity):
Nandrolone is not c-17 alpha alkylated, and not known to have 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. Studies
administering 600 mg of nandrolone decanoate per week for 10 weeks demonstrated a 26%
reduction in HDL cholesterol levels.478 This suppression is slightly greater than that reported
with an equal dose of testosterone enanthate, and is in agreement with earlier studies showing
a slightly stronger negative impact on HDL/LDL ratio with nandrolone decanoate as
compared to testosterone cypionate.479 Nandrolone should still have a significantly weaker
impact on serum lipids than c-17 alpha alkylated agents. Anabolic/androgenic steroids may
also adversely effect blood pressure and triglycerides, reduce endothelial relaxation, and
support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular
disease and myocardial infarction.
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):
All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are
expected to suppress endogenous testosterone production. Studies administering 100 mg
injection of nandrolone phenylpropionate demonstrated a rapid suppression of serum
testosterone following a single injection. Testosterone levels declined to approximately 30%
of initial level by day 3 after drug administration, and stayed suppressed for approximately 13
days. Regular use is expected to significantly lengthen the endogenous hormone recovery
window. It is believed that the progestational activity of nandrolone notably contributes to the
suppression of testosterone synthesis during therapy, which can be marked in spite of a low
tendency for estrogen conversion.480 Without the intervention of testosterone-stimulating
substances, testosterone levels should return to normal within 2-6 months of drug secession.
Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid
abuse, necessitating medical intervention.
Administration (Men):
For general anabolic effects, early prescribing guidelines recommend a dosage of 25-50 mg
per week for 12 weeks. The usual dosage for physique- or performance-enhancing purposes
is in the range of 200-400 mg per week, taken in cycles 8 to 12 weeks in length. This level is
sufficient for most users to notice measurable gains in lean muscle mass and strength. Note
that due to the fastacting nature of the phenylpropionate ester, the weekly dosage is usually
subdivided into 2 separate applications spaced evenly apart.
Administration (Women):
For general anabolic effects, early prescribing guidelines recommend a dosage of 25-50 mg
per week for 12 weeks. When used for physique- or performance-enhancing purposes, a
dosage of 50 mg per week (given in a single weekly injection) is most common, taken for
cycle lasting 4 to 6 weeks. Higher doses or longer durations of use are discouraged due to
potential for androgenic side effects. Although only slightly androgenic, women are
occasionally confronted with virilization symptoms when taking this compound. Should
virilizing side effects become a concern, nandrolone phenylpropionate should be discontinued
immediately to help prevent a permanent appearance.
