Finasteride History and Overview
Finasteride is the generic name for the brand name drug Proscar, better known as Proscar.
Finasteride was originally developed and manufactured by Merck Pharmaceuticals and was approved by the FDA for use in the prescription market in 1992 under the brand name Proscar.
It was initially approved for use in the treatment of benign prostatic hyperplasia (BPH), a benign enlargement of the prostate.
However, in 1997, the FDA approved finasteride for use in the treatment of male pattern baldness (MPB).
For the treatment of MPB, finasteride is sold under a different brand name, Propecia.
The difference between Proscar and Propecia is that Propecia contains only one-fifth of the total Proscar dose.
Finasteride is commonly used by bodybuilders and athletes for the same reasons it is used in medical settings: to slow or prevent male pattern baldness associated with dihydrotestosterone (DHT) and to mitigate or prevent the possibility of benign prostatic hyperplasia from the same cause.
When bodybuilders and athletes take high doses of testosterone, they often experience a marked increase in androgenic side effects, including increased aggression, increased body hair, oily skin, acne, prostate enlargement, and the potential for male pattern baldness.
This is primarily due to the conversion of testosterone to dihydrotestosterone (DHT), a much more potent androgen.
While testosterone itself is moderately androgenic, DHT is many times more potent as a male hormone. Testosterone is converted (or more formally reduced) to DHT by an enzyme called 5-alpha reductase (5AR).
This enzyme is present in high concentrations in tissues such as the scalp, prostate, and under the skin.
As testosterone circulates in the bloodstream and passes through these tissues, the 5AR enzyme binds to a specific percentage of the testosterone present and reduces it to dihydrotestosterone.
As you'll see shortly, finasteride is an inhibitor of the 5-alpha reductase enzyme, and this is the active way it works in the body.
It's important to note that 5AR inhibitors like finasteride only succeed in reducing or preventing the conversion of testosterone to DHT, and are virtually useless if the athlete or bodybuilder is using other anabolic steroids that avoid the 5AR enzyme entirely (or anabolic steroids that are already derivatives of DHT).
Bodybuilders and athletes typically use finasteride in a cycle with moderate to high doses of testosterone.
Therefore, it should come as no surprise that finasteride does absolutely nothing to mitigate, prevent, or stop the androgenic effects of anabolic steroids such as
(Trenbolone, Nandrolone (Deca-Durabolin), Anavar (Oxandrolone), Winstrol (Stanozolol), Masteron (Drostanolone), and many other compounds).
Chemical Properties of Finasteride
Chemically, finasteride is known as a synthetic 4-azasteroid.
As you just learned, 5-alpha reductase is responsible for the conversion of testosterone to DHT in the body.
Finasteride works to prevent this process by binding to and inhibiting the 5-alpha reductase enzyme itself.
This mode of action allows finasteride to effectively reduce DHT concentrations in the plasma, thereby mitigating and minimizing the negative androgenic effects of high serum DHT levels.
Studies have shown that finasteride is effective in reducing serum DHT levels by as much as 65% 24 hours after administration of a 1 mg tablet.
Specifically, finasteride inhibits the type II 5-alpha reductase enzyme.
There are actually two variants of the 5AR enzyme in the body (type-I and type-II).
The difference between the two is that one is found in higher concentrations in some body tissues than the other.
Specifically, the type-I 5AR enzyme is found in higher concentrations in the liver and under the skin.
The type-II 5AR enzyme is found in higher concentrations in the prostate and scalp.
In fact, the type-II variant is responsible for about two-thirds of the total concentration of DHT in the body than type-I, which is responsible for the remaining one-third.
Since finasteride only inhibits type-II, it stands to reason that it would be much more effective in preventing or treating MPB and hair loss than in addressing the other androgenic effects of oily skin/acne.
The important thing to note here is that while finasteride is very effective as a DHT inhibitor, it is not able to block DHT conversion to anywhere near 100%, and studies have shown that DHT does not work equally in all body tissues of concern.
Because finasteride prevents testosterone from converting to DHT, studies have shown that it can increase circulating plasma testosterone levels by about 15%.
Of course, this is because finasteride leaves less of the 5AR enzyme in the body to interact with testosterone.
Those considering using finasteride for androgenetic alopecia (hair loss), oily skin, acne, BPH, or other negative androgenic effects should understand that reductase inhibitors like finasteride do not provide 100% protection against these effects.
Drugs like finasteride will only mitigate or reduce/diminish these effects, not eliminate them.
Similarly, finasteride will not stop hair loss after it has started, nor will it reverse it, as is often misunderstood.
Finasteride Side Effects
Because finasteride is a very specific drug in its mode of action, it has few peripheral or residual effects on other parts of the body, but it does have potential side effects.
Finasteride does not interact with androgen or estrogen receptors, so it has no direct androgenic, estrogenic, antiandrogenic, or antiestrogenic effects.
It also has no effect on other hormones in the body such as cortisol, thyroid hormones, luteinizing hormone (LH), follicle stimulating hormone (FSH), and studies have shown that it does not affect cholesterol levels.
However, studies have shown that 8.1% of subjects and patients reported erectile dysfunction, 6.4% reported decreased libido (sex drive), and a small minority of less than 1% reported ejaculation problems, gynecomastia (breast tissue development), and strange rashes.
Most finasteride side effects are caused by the ability of finasteride to lower DHT levels in the body. It is important to understand that DHT is a potent androgen and part of its responsibility is to maintain normal male secondary sex characteristics as well as sexual function.
It stands to reason that lowering the level of DHT in circulating plasma will reduce both the positive and negative androgenic effects of DHT.
This is very important and should be kept in mind by those considering using finasteride. Additionally, studies and research have shown that strong androgens actually act as anti-estrogens in the body.
This is also the case with DHT, and when DHT levels in the plasma are reduced by finasteride, estrogen becomes 'dominant' and some users may experience some degree of estrogenic side effects such as gynecomastia or breast tenderness.
Finasteride dosing and administration
For the treatment of androgenetic alopecia (male pattern baldness), a dose of 1 mg is usually taken daily for 6 to 12 months.
Higher doses are prescribed for the treatment of benign prostatic hyperplasia (enlarged prostate), usually 5 mg daily over a longer period of time.
The recommended dose of finasteride for bodybuilders and athletes who want to reduce the androgenic effects of testosterone conversion to DHT is 1 mg per day for the duration of testosterone use.
Additionally, many athletes and bodybuilders choose to use finasteride only as needed and not automatically with each cycle.
