For those experiencing hair loss, medication is one of the most popular treatment options. People typically begin with topical treatments like minoxidil (better known as Rogaine) because it can be purchased over-the-counter without a prescription.
If minoxidil doesn’t work to their satisfaction, they usually talk to their doctor about the oral medication finasteride (Propecia). Finasteride is the first medication of its kind, and has proven to be effective in the vast majority of people who take it.
But those who have tried almost every medication on the market (shampoos, creams, supplements, etc.) are usually skeptical that an oral medication would do any good. And rightly so — there are a lot of products that aren’t effective whatsoever and plenty of people have wasted far too much money on them.
Sometimes during clinical trials in humans, drug companies discover side effects that are actually a bit helpful for unrelated ailments. Perhaps the most famous example is sildenafil citrate, better known as Viagra — a medication developed by Pfizer to treat high blood pressure and angina (chest pain often linked to heart disease).
During clinical trials, researchers found the sildenafil citrate wasn’t doing much to help people’s blood pressure, but men were experiencing… well, a different, unexpected side effect. Of course, this led to the re-purposing and redevelopment of said drug.
Like Viagra and a few other medications, finasteride isn’t used for its original intended purpose. Merck developed a medication called Proscar (in 5mg doses) to treat enlarged prostate glands. As with Viagra, participants in the clinical trials reported a fortunate side effect. This time, it was additional hair growth.
Because the drug was already approved for a different purpose, Merck decided to re-purpose it and create the first hair loss medication in a pill form.
After additional clinical trials to determine dosage in 1997, the FDA approved a 1mg dose to treat male pattern baldness, and Propecia was born. Propecia became the first drug of its kind to treat androgenic alopecia and remains extraordinarily popular today.
The key to Merck’s success with finasteride lies in the drug’s ability to reduce a very specific enzyme called 5-alpha-reductase. This is important because 5-alpha-reductase is what creates the byproduct of testosterone believed to be the main culprit behind male pattern baldness: dihydrotestosterone (DHT).
While some hair loss is caused by hormone imbalances, illness or stress, male pattern baldness is caused by hair follicles that are sensitive to DHT. DHT causes hair follicles to shrink over time, and as they shrink, they produce fewer hairs. (While we often think that one hair follicle equals one hair, each follicle can produce anywhere from one to five hairs.)
As the follicles shrink, the hairs they produce may change in texture and thickness, and they’ll eventually stop producing hairs altogether. And because the follicles on the top and crown of the head tend to contain DHT-sensitive follicles, we often see male pattern baldness begin with a receding hairline on the forehead or thinning hair at the crown (the infamous “bald spot”).
In later stages of male pattern baldness, men are typically left with a “horseshoe” pattern, with remaining hair only on the sides and back of the head — although some men also experience thinning hair in those areas as well.
But by reducing the 5-alpha-reductase enzyme, Propecia reduces the prevalence of DHT, which means the drug is essentially eliminating the cause of hair loss in the first place (again, assuming the hair loss is being caused by DHT and not another health issue).
Because finasteride consistently reduces the 5-alpha-reductase enzyme, it takes some time before the effects start to become noticeable — typically about six months, but it could take up to one year. Stopping the medication will result in increased production of the 5-alpha-reductase enzyme again, which will lead to additional DHT production, and of course, hair loss.
Any hair re-grown as a result of finasteride will fall out, and hair loss will resume as it had been occurring prior to the patient taking the medication. Therefore, most people who begin taking Propecia intend to continue taking it for the foreseeable future.
If the patient hasn’t seen any meaningful results after taking finasteride for one year, it’s unlikely that they ever will. In this case, the patient may be one of the small percentage of men in which Propecia is ineffective. At this point, the prescribing doctor will likely advise him to stop taking the medication and look into hair transplants (like follicular unit extraction) instead.
Propecia is largely well-accepted by those who take it. However, some side effects are possible with any drug. Finasteride has a variety of possible side effects, ranging from serious to innocuous.
Most commonly, some men experience lower libido or the inability to have or keep an erection. Others experience common cold symptoms, like a runny nose, drowsiness or congestion. The good news is that these side effects tend to dissipate as the body adjusts to the medication.