Finasteride for Hair Loss: Side Effects, Dosage & More
If you’ve been looking into Propecia®, or its generic finasteride, for hair loss, you probably have many questions. How does finasteride work for hair loss? And does finasteride have side effects? Good news — as you might expect from the headline, we’re here to answer your questions about oral finasteride.
The first thing to know is that oral finasteride is a popular and safe medication for hair loss that’s effective for many men with few adverse effects. In fact, it is one of the few treatment options proven effective for male pattern baldness on the market today. Finasteride prevents further hair loss by protecting follicles and promoting hair growth on the scalp.
Below, we’ll get into the specifics of how finasteride works, how much to take, what side effects to expect, and more.
Finasteride Uses
Finasteride, a generic medication also sold as Propecia® or Proscar®, is used to treat male androgenetic alopecia, also known as male pattern hair loss.
Originally, finasteride was approved by the U.S. Food and Drug Administration (FDA) to treat benign prostatic hyperplasia (BPH), a form of non-cancerous prostate enlargement, under the brand name Proscar. Several years later, the medication was approved for the treatment of hair loss and sold under the brand name Propecia.
Today, both versions of finasteride — the higher-dose version used to treat an enlarged prostate gland and the lower-dose version used for hair loss — are available as generics and under various brand names.
Finasteride comes in tablet form and is designed for daily use. It’s typically prescribed at 1 mg per day as a treatment for hair loss (when used for BPH, it’s prescribed at a 5 mg dose, which is not any more effective for treating hair loss).
How Does Oral Finasteride Work for Hair Loss?
Chances are, you’re here because you’re curious about finasteride as a hair loss treatment. Here’s how it helps fight hair loss and facilitate hair regrowth.
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, this androgen hormone 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.
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 using finasteride as recommended lowers serum DHT levels (the amount of DHT in your bloodstream) by more than 70 percent. This reduction in DHT can slow or even stop hair loss. Many men even notice a significant degree of hair regrowth in areas of scalp hair affected by male pattern baldness after starting treatment with finasteride.
Does Finasteride for Hair Loss Work?
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 another study published in the Journal of the American Academy of Dermatology that involved 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.
Which Types of Hair Loss Does Finasteride Treat?
Currently, finasteride is FDA-approved to treat male pattern baldness, the most common type of hair loss in men.
Because finasteride works on a hormonal level, it’s not a good choice for hair loss that does not have a hormonal component, including:
Telogen effluvium: Telogen effluvium is a temporary form of hair loss caused by severe stress, infections, surgery, illnesses that cause fever, nutritional deficiencies, hormonal changes, and certain types of medication.
Alopecia areata: A form of autoimmune hair loss, alopecia areata can cause hair to fall out in small, round patches. Experts aren’t entirely sure what triggers this type of hair loss, although it may be related to stress, infections, and certain medications. Still, finasteride for alopecia likely isn’t a fix.
Tinea capitis: Also referred to as scalp ringworm, tinea capitis is a type of fungal infection that can cause patchy hair loss.
Since DHT doesn’t cause these types of hair loss, finasteride isn’t effective at slowing them down, stopping them, or reversing their effects.
Side Effects of Finasteride Pills for Hair Loss
Like almost all medications, finasteride can cause side effects. Most side effects of finasteride for hair loss are generally mild, although some may impact your quality of life.
Potential side effects of finasteride include:
Decreased libido
Inability to get or maintain an erection (erectile dysfunction)
Pain or discomfort affecting the testicles
Ejaculation disorders or problems, such as decreased ejaculatory volume
Changes in mood or depression
Sexual side effects — such as erectile dysfunction, difficulty ejaculating, and a weaker sex drive — can sound alarming, but they are rare.
“Oral finasteride is one of only two FDA-approved medications for hair loss, the other being topical minoxidil, and there is a lot of independent data showing its effectiveness. I always discuss the potential side effects of finasteride. However, the risk of sexual side effects is very low,” says Knox Beasley, MD, a board-certified dermatologist and one of our medical reviewers.
Some men who use Proscar also report side effects like breast tenderness and skin rashes, although it’s uncommon in the low-strength version of finasteride used to treat hair loss. 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.
Although the risk is low, finasteride is also associated with an increased risk of getting a more severe form of prostate cancer called high-grade prostate cancer. In men over 55 years old, the risk of developing high-grade prostate cancer increases from 1.0 percent to 1.8 percent with the use of 5mg finasteride. However, it’s important to note that this incidence is from a far higher dosage of finasteride (5 mg tablet vs. 1 mg) than the dose that’s used to treat hair loss.
We also have some more good news about side effects: Per the FDA label for finasteride, no significant drug interactions are associated with this medication.
Even so, be sure to seek medical advice and tell a healthcare professional about all your current medications, supplements, and health risks before you take finasteride. In particular, people who are breastfeeding, pregnant, or who have liver disease should consult their healthcare provider before taking finasteride.
Are Finasteride Side Effects Serious?
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, the high-strength 5mg version of finasteride, only a small percentage of men report the side effects just mentioned.
For example, in clinical studies of finasteride for BPH, just over 8 percent of men reported an effect on their erections, with 6.4 percent and 3.7 percent of men reporting decreases in libido and 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 1 mg 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 took a non-therapeutic placebo also reported these side effects. Further, in clinical trials, these side effects tended to go away on their own, both in men who discontinued finasteride and those who stayed on the medication.
How Often Do Side Effects of Finasteride Last?
As with many other medications, some side effects of finasteride may fade away or become less severe with long-term use. Still, although uncommon, a small percentage of men may continue to experience adverse events even after discontinuing the use of 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.
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Proper Use of Oral Finasteride
Finasteride is typically sold in two dosages.
As a treatment for male pattern baldness, the finasteride dosage is 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.
Meanwhile, 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 generic forms of finasteride and the brand-name medication Proscar.
Oral finasteride should be taken daily at around the same time every day (it doesn’t matter when that is as long as you’re consistent). It can be taken with or without food and should be stored at room temperature. If you miss a dose of finasteride, you should not take two pills the next day (instead, resume your medication as normal).
If you experience an allergic reaction while using finasteride, stop taking it and contact a healthcare provider.
How Long Does Finasteride for Hair Growth 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 for several months.
On average, it takes three to four months to see new hair or any other improvements from finasteride.
This isn’t because the medication isn’t working. In fact, finasteride starts reducing DHT levels as soon as your body absorbs it. But because of the length of the hair growth cycle, you’ll need to be patient before the effects of finasteride become visible.
Still, 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. And after one year of continuous use, you should be able to see more “final” results from finasteride.
Is Finasteride Worth It?
Ultimately, the question of whether finasteride is worth it is up to you to answer. If you’re willing to be consistent with taking the medication and have the patience to wait a few months to start seeing real results, you will likely find that finasteride for hair loss is worth it.
If you don’t like the idea of taking an oral medication, finasteride is also available in a topical form (that means you put it directly on your scalp). It currently does not have FDA approval specifically for this use, but studies show that topical finasteride is generally well-tolerated and has less systemic exposure, which may make it easier for people experiencing side effects to tolerate.
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The Final Word: Oral Finasteride for Hair Growth
Oral 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, hair loss 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 this condition, taking early action can help you to enjoy a fuller, thicker head of hair throughout your life. Before taking the pill, however, just make sure you understand how the medication works and which types of hair loss it can actually treat, as well as what potential side effects you could experience and how to properly use the medication.
Ready to start treating your hair loss today? 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.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment or medication.