Finasteride for Hair Loss: Side Effects, Dosage and More
Reviewed by Kristin Hall, FNP
Written by Our Editorial Team
You’ve suspected it for some time, but now it’s undeniable -- you’re losing your hair. Whether it takes the form of a receding hairline, a bald spot around your crown or diffuse thinning on your entire scalp, hair loss is never a good thing.
As a man, your hair is an important part of your identity and your hairstyle is a testament to your personality. But losing your hair doesn’t have to mean losing yourself.
The good news is that hair loss from male pattern baldness is almost always treatable. In fact, if you take action quickly, it’s often possible to prevent any further hair loss and even regrow some or all of the hair in areas of your scalp affected by hair loss.
One of the most effective hair loss treatments available is finasteride, a medication that reduces your body’s production of dihydrotestosterone, or DHT.
Used correctly, finasteride can produce natural-looking results without the cost or inconvenience of options like surgery or a hairpiece.
Below, we’ve explained what finasteride is, as well as how it works to slow down, stop and even reverse the effects of male pattern baldness.
We’ve also covered everything you need to know before using finasteride, from side effects and finasteride interactions to simple tips and techniques that you can use to get the best possible results.
What is Finasteride?
Finasteride is a prescription medication that’s FDA-approved for the treatment of androgenetic alopecia, or male pattern baldness.
You may have heard of finasteride as Propecia® or Proscar®. Propecia is a brand name that’s used to market finasteride sold by the pharmaceutical company Merck & Co.
Originally, finasteride was approved by the FDA as medication for benign prostatic hyperplasia, or BPH -- a form of non-cancerous prostate enlargement -- under the brand name Proscar®.
Several years later, it was approved for hair loss and sold as Propecia. Today, both versions of finasteride -- the higher-dose version used to treat an enlarged prostate gland and the lower-dose version that’s used for hair loss -- are available as generics under a variety of brand names.
Finasteride comes in tablet form and is designed for daily use, according to an article published in the book, StatPearls. As a treatment for hair loss, it’s typically prescribed at a dosage of 1mg per day.
How Does Finasteride for Hair Loss Treatment Work?
Finasteride tablets belong to a class of medications called 5 alpha-reductase inhibitors, or 5-ARIs. It works by inhibiting the action of the 5 alpha-reductase enzyme, which is involved in converting testosterone into the hormone dihydrotestosterone (DHT).
DHT plays a central role in male pattern baldness. If you’re genetically prone to hair loss, DHT can bind to receptors in your hair follicles and cause them to miniaturize, resulting in a gradual loss of hair around your hairline, crown or across your scalp.
Our guide to DHT and male hair loss discusses the effects of DHT on your hair follicles in more detail.
By inhibiting the 5 alpha-reductase enzyme, finasteride significantly reduces the amount of DHT in your bloodstream, shielding your hair follicles from DHT-related damage.
Research shows that a typical use of finasteride lowers serum DHT levels (the amount of DHT in your bloodstream) by more than 70 percent.
This can result in your hair loss slowing, or even stopping completely. Many men even notice a significant degree of hair regrowth in areas of the scalp affected by male pattern baldness after starting treatment with finasteride.
So, does finasteride produce results? For most men, absolutely.
Research shows that finasteride works, often very well. In long-term, placebo-controlled clinical trials published in the Journal of Investigative Dermatology Symposium Proceedings, 90 percent of men with hair loss who used finasteride either maintained their hair or saw improvements in hair growth.
In comparison, 75 percent of men who used a non-therapeutic placebo experienced worsening hair loss over the same period.
In one study published in the Journal of the American Academy of Dermatology involving two one-year clinical trials, researchers found that finasteride produced a more than 15 percent increase in hair count at the vertex scalp (the crown, or area at the top of the scalp) in men with male pattern baldness.
Another study from Japan, which covered 10 years of finasteride use, found that more than 90 percent of men with androgenetic hair loss who use finasteride experience improvements.
In short, finasteride works, with most men experiencing improvements in their hair growth and density with treatment.
Hims has helped thousands of men regrow their hair
Which Types of Hair Loss Does Finasteride Treat?
It’s common and normal to experience a little bit of hair loss on a daily basis. In fact, most guys shed 50 and 100 hairs per day, even if they aren’t affected by male pattern baldness.
This level of hair shedding occurs as part of your natural hair growth cycle. As hair grows to its full length, it starts to transition from active growth to rest.
Eventually, it’s replaced by new hair, resulting in a certain amount of daily shedding.
This level of hair loss is so insignificant that it’s usually not even noticeable. If you’ve begun to experience noticeable hair loss, however, it could be a problem.
Currently, finasteride is approved by the FDA to treat male pattern baldness, which is the most common type of hair loss in men.
However, male pattern hair loss isn’t the only type of hair loss. Other types of hair loss that can affect you may include:
Telogen effluvium. This is a temporary form of hair loss that’s caused by severe stress, infections, surgery, illnesses that cause fever, nutritional deficiencies, hormonal changes and certain types of medication.
Alopecia areata. This is a form of autoimmune hair loss, in which your hair can fall out in small, round patches. Experts aren’t completely sure about what triggers this type of hair loss, although it may be related to stress, infections and certain medications.
Tinea capitis. Also referred to as scalp ringworm, this is a type of fungal infection that can cause patchy hair loss.
Since these types of hair loss aren’t caused by DHT, finasteride isn’t effective at slowing them down, stopping them or reversing their effects.
Finasteride Side Effects
Like almost all medications, finasteride can cause side effects. Most of the adverse effects of finasteride are mild, although some may have an impact on your quality of life.
Potential side effects of finasteride include:
Inability to get or maintain an erection (erectile dysfunction)
Pain or discomfort that affects the testicles
Ejaculation disorders or problems, such as decreased ejaculatory volume
Changes in mood or depression
Although it’s uncommon in the low-strength version of finasteride that’s used to treat hair loss, some men who use Proscar, a stronger version of finasteride for BPH, also report side effects such as breast tenderness and skin rashes. If you experience breast tenderness or nipple discharge, report these side effects to a healthcare provider, as they may be a sign of breast cancer.
Sexual side effects, such as erectile dysfunction, difficulty ejaculating and a weaker sex drive, can sound alarming.
We have a more in-depth article that goes over the link between ED and hair loss if you would like more information.
However, it’s important to look at these side effects in context before you write off finasteride as a hair loss treatment.
Even in studies of Proscar, a high-strength 5mg version of finasteride, only a small percentage of men report these side effects.
For example, in clinical studies of finasteride for BPH, just over eight percent of men reported an effect on their erections, with 6.4 percent and 3.7 percent of men reporting decreases in libido and a reduced ejaculation volume, respectively.
Other finasteride side effects, such as breast tenderness and rash, were reported by less than one percent of men who used finasteride in clinical trials.
In clinical trials involving the 1mg per day dose used to treat hair loss, sexual dysfunction from finasteride was far less common, with just 1.8 percent of men reporting a weakened libido and 1.3 percent reporting erectile dysfunction.
It’s worth noting that many men who were given a non-therapeutic placebo also reported these side effects.
As with many other medications, some side effects of finasteride may fade away or become less severe with long-term use.
Although uncommon, a small percentage of men may continue to experience adverse events after discontinuation of treatment with finasteride.
Our guide to the side effects of finasteride looks at this data in more detail and provides some additional information on what you should expect while using finasteride for hair loss.
Per the FDA label for finasteride, there are no significant drug interactions associated with this medication.
Although low, finasteride is associated with an increased risk of getting a more serious form of prostate cancer, called high-grade prostate cancer.
In men over 55 years of age, the risk of developing high-grade prostate cancer increases from 1.0 percent to 1.8 percent with the use of 5mg finasteride.
It’s important to note that this incidence of this severe side effect is from a far higher dosage of finasteride (5 mg tablet vs. 1 mg) than the dose that’s used to treat hair loss.
Be sure to seek medical advice and discuss all patient information with a healthcare professional before using finasteride, such as current medications, supplements, and health risks.
Finasteride is typically sold in two dosages. As a treatment for male pattern baldness, it’s used at a dosage of 1 mg per day.
This is the dose of finasteride you’ll find in most generic versions of finasteride for hair loss, as well as the brand name medication Propecia.
As a treatment for benign prostatic hyperplasia (BPH), finasteride is used at a dosage of 5 mg per day.
This dose can be found in most generic versions of finasteride and in the brand name medication Proscar.
How Long Does Finasteride Take to Work?
Finasteride is effective, but there’s one catch: it doesn’t work overnight. To get consistent results from finasteride, you’ll need to have a long-term outlook and take it consistently over the course of several months.
On average, it takes three to four months before you’ll usually be able to see any improvements from finasteride.
This isn’t because the medication isn’t working. In fact, finasteride starts reducing DHT levels as soon as it’s absorbed by your body.
However, your hair takes time to grow, meaning you’ll need to be patient before the effects from finasteride become visible.
Data from clinical trials shows that most guys experience improvements from finasteride after a year of consistent use.
In short, once you start using finasteride, you can expect to see some change in your hair after a few months.
After one year of continuous use, you should be able to see more “final” results from finasteride.
Other Treatments for Hair Loss in Men
For most men, finasteride is an effective option for treating and preventing hair loss from male pattern baldness.
However, it’s not the only hair loss treatment that’s available. Other affordable and effective hair loss treatment options include:
Minoxidil. A topical medication, minoxidil helps to improve blood flow to the scalp and stimulate hair growth. Research shows that minoxidil is particularly effective when it’s used at the same time as finasteride. We offer minoxidil solution and minoxidil foam online. You can also purchase finasteride and minoxidil together in our Hair Power Pack.
Hair loss prevention shampoo. Many shampoos, including those that contain active ingredients such as saw palmetto and ketoconazole, are formulated to prevent excess hair shedding and promote optimal hair growth. OurHair Thickening Shampoo uses saw palmetto to target DHT at the scalp level and promote volume and moisture.
What Treatments DON’T Work or Cost Too Much?
There are countless men out there who are desperate to stop male pattern baldness, so they’ll try just about everything they can.
Unfortunately, many of the hair loss treatments currently on the market either don’t work, or are effective but prohibitively expensive. These include:
Laser combs and other products. Often referred to as low-level laser therapy (LLLT), these products use laser light to stimulate the hair follicles. Research is mixed on their effectiveness and many devices of this type cost hundreds or thousands of dollars.
Hair oils. Several essential oils are marketed as treatments for pattern hair loss. While some have shown mild effects in small studies, none are as effective as FDA-approved hair loss treatments such as finasteride and minoxidil.
Corticosteroids. These medications are used to reduce inflammation, which can cause hair loss in certain situations. While they may be useful for some non-hormonal forms of hair loss, there’s no evidence that they prevent or slow down pattern hair loss.
Topical corticosteroids. While these may be prescribed for certain inflammatory scalp conditions, they’re not used for male pattern baldness.
Hair transplant surgery. Although hair transplant surgery is effective, it’s an expensive option. The cost of a hair transplant can vary from a few thousand to tens of thousands of dollars, depending on the extent of your hair loss and number of grafts required.
Out of all the hair loss remedies out there, only two offer a good combination of affordability and efficacy -- oral finasteride and topical minoxidil.
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No matter the treatment plan, the best place to start is somewhere. Early action is the best hair loss prevention.
Using Finasteride for Hair Loss
Finasteride is popular for a reason -- more than any other hair loss medication, it’s effective at slowing down, stopping and even reversing the effects of male pattern baldness.
Losing your hair is never easy, but fortunately, it isn’t something you have to live with. If you’re one of the tens of millions of men in the United States affected by hair loss, taking action early can help you to enjoy a fuller, thicker head of hair throughout your life.
We offer finasteride and other proven, science-based hair loss medications online, following a consultation with a healthcare provider who will determine if a prescription is appropriate.