Raloxifene Hydrochloride (AKA Evista)
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Chemical Name |
[6-hydroxy-2-(4-hydroxyphenyl)- benzothiophen-3-yl]- [4-[2-(1-piperidyl)ethoxy]phenyl] -methanone |
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Molecular Weight |
473.584 g/mol or |
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Formula |
C28H27NO4S |
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Original Manufacturer |
Eli Lilly and Co. |
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Half Life |
27.7 hours |
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Detection Time |
Currently unknown |
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Anabolic Rating |
N/A |
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Androgenic Rating |
N/A |
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Overview and History of Raloxifene
Raloxifene hydrochloride (trade name Evista) is a fairly new anti-estrogen drug on the prescription market, belonging to a class of drugs known as selective estrogen receptor modulators (SERMs), which is actually a subcategory of a broader class of drugs known as anti-estrogens.
A subcategory of anti-estrogens is the aromatase inhibitors (AIs), which include the three most common aromasins (Exemestane), Arimidex (Anastrozole), and Letrozole (Femara), although many other aromatase inhibitors exist.
SERMs and AIs make up a broad class of anti-estrogens.
SERMs and AIs differ significantly in their mechanisms of action and how they work physiologically.
As with all profiles covering SERMs and AIs, the differences between these two classes of anti-estrogenic drugs should be clarified and explained before discussing raloxifene in particular.
It is common for the anabolic steroid use and bodybuilding community to confuse the two, giving them the wrong (or opposite) anti-estrogenic properties.
SERMs act on estrogen receptors in various tissues in the body, specifically blocking the activity of estrogen at receptor sites in breast tissue (also known as estrogen antagonism).
In effect, they occupy the estrogen receptor and “boot” the estrogen that is occupying the receptor, preventing estrogen from gaining access to the receptor site.
In addition, SERMs can and do act as estrogen agonists in other tissues in the body (e.g., the liver).
As an estrogen agonist, the drug does the opposite of the actions described above, instead binding to the receptor and initiating estrogenic effects in that tissue.
As a result, SERMs only act to antagonize (or distress) the effects of estrogen in specific tissues, and do not reduce the total circulating plasma concentration of estrogen in the body, so some estrogenic side effects, such as water retention and bloating, cannot be treated with SERMs.
Aromatase inhibitors, on the other hand, bind to the aromatase enzyme, the enzyme that converts (aromatizes) androgens into estrogen, thereby neutralizing the root cause of estrogen production in the body.
When the aromatase enzyme is inhibited and neutralized, it cannot act to produce estrogen in the body, effectively reducing the total circulating plasma estrogen levels in the body.
Aromatase inhibitors can and do eliminate estrogenic side effects that SERMs are unable to treat, such as bloating and water retention.
Raloxifene, in particular, is a non-steroidal SERM that belongs to the benzothiophene family.
Raloxifene works very similarly to Nolvadex (tamoxifen) in its mode of action, exhibiting both estrogen agonist and estrogen antagonist effects in various tissues of the body.
Specifically, raloxifene acts as an estrogen antagonist in breast and uterine tissue, while acting as an estrogen agonist in bone tissue.
In fact, raloxifene has been used in medicine to prevent osteoporosis in postmenopausal women because of its estrogenic activity in bone.
Nolvadex, on the other hand, is known to act as an estrogen antagonist in bone, which is obviously problematic for female breast cancer patients who are prescribed Nolvadex.
Given these characteristics, it's easy to understand why raloxifene has demonstrated clear advantages over Nolvadex and has proven to be a novel new drug for the treatment of a variety of postmenopausal conditions in female patients.
Eli Lilly & Company developed raloxifene, and raloxifene (trade name Evista) was approved by the FDA in 1997 and entered the prescription market.
Initially, it was used to treat osteoporosis (because it exerts an estrogenic effect on bone tissue, increasing bone density in patients).
Ten years later, in 2007, raloxifene's approved use was expanded to include the treatment of breast cancer. It has since become a very popular drug, used in more than 50 countries around the world.
Because raloxifene has large differences in the selectivity of its estrogenic and antagonistic actions in different tissues of the body, its application in other diseases such as prostate cancer, acromegaly, uterine cancer, cardiovascular disease, and breast cancer continues to be studied [1].
Bodybuilders and anabolic steroid users are attracted to the use of raloxifene because of its properties as an anti-estrogen, which combats estrogen-related side effects that typically result from the use of aromatizing androgens, which increase the plasma concentration of estrogen in the body.
A common estrogenic side effect that results from this is the development of gynecomastia.
In the realm of gynecomastia specifically, raloxifene has actually demonstrated more promising results than Nolvadex (tamoxifen) [2].
Like all SERMs and anti-estrogens, raloxifene also has significant benefits in stimulating endogenous natural testosterone production in men, with studies showing that 120 mg of raloxifene per day increased serum testosterone levels by 20% [3].
Chemical Properties of Raloxifene
Raloxifene (Evista) is a non-steroidal selective estrogen receptor modulator (SERM) that exhibits both mixed and antagonistic actions with respect to estrogen at different sites in the body.
Raloxifene belongs to a family of compounds known as benzothiophene compounds.
Other SERMs, such as Clomid (clomiphene citrate) and Nolvadex, are also SERMs, but instead belong to the triphenylethylene family of compounds.
While raloxifene is not in the same family of compounds, it is actually very closely related to Nolvadex and Clomid.
Properties of Raloxifene
As previously discussed, raloxifene is an anti-estrogen, but it does not lower the total plasma concentration of estrogen in the body.
Instead, it works by blocking the effects of estrogen at estrogen receptors in certain tissues in the body (breast tissue) and promoting the effects of estrogen in other tissues (bone and uterine tissue).
This makes it effective in the prevention and/or treatment of gynecomastia.
Raloxifene also acts as an estrogen antagonist in the hypothalamus, stimulating gonadotropin production (LH and FSH) in the pituitary gland, which ultimately increases endogenous testosterone levels.
