Medically reviewed by Katelyn Hagerty, FNP
Written by Our Editorial Team
Last updated 12/2/2022
Finasteride, a prescription medication for male pattern baldness, is one of the most popular hair loss treatments on the market.
It’s also one of the most effective treatments, with a proven track record of helping men stop hair loss, keep the hair they still have and, in some cases, even grow back “lost” hair.
Like most hair loss treatments, results from finasteride aren’t instant. Depending on the severity of your hair loss, it may take several months before you’re able to see any improvements in the thickness, density and general appearance of your hair.
Below, we’ve discussed what finasteride is, as well as how it works as a medication for treating androgenetic alopecia, or pattern hair loss, in men.
We’ve also explained how long finasteride takes to work, as well as techniques that you may be able to use for faster, better results while using this medication.
Finasteride belongs to a class of drugs called 5-alpha-reductase inhibitors, or 5ARIs. It works by blocking the effects of the enzyme 5-alpha-reductase, which is responsible for converting some of your body’s testosterone into the hormone dihydrotestosterone, or DHT.
DHT is a powerful androgen hormone, or male sex hormone. Before birth, it plays a key role in the development of male genitalia.
During puberty, DHT is one of several hormones responsible for the growth of your facial hair, body hair and other male secondary sex characteristics.
As an adult, DHT doesn’t play such a significant role in your physical development. However, it can bind to receptors throughout your body and cause certain changes.
One of these is prostate growth. In some men, DHT activity is significantly increased in the prostate gland and can contribute to issues such as benign prostatic hyperplasia (BPH, or enlarged prostate).
Another is male pattern baldness. In men genetically predisposed to hair loss, excessive DHT can bind to receptors in the scalp and cause the hair follicles to gradually miniaturize until they’re no longer capable of producing healthy hairs.
We’ve explained this process in more detail in our full guide to DHT and its role in male pattern baldness.
Enter finasteride. By inhibiting the effects of the 5-alpha-reductase enzyme, finasteride prevents your body from converting testosterone to dihydrotestosterone.
This significantly lowers the amount of DHT that’s present in your bloodstream and shields your hair follicles from the DHT-related damage that can affect your head of hair.
Research has found that finasteride can reduce DHT levels in the prostate by 90 percent, and in the blood by up to 70 percent.
The result of this process is significantly reduced hair loss and, in some men, a large increase in hair growth.
In one study, researchers found that men with androgenetic alopecia (a clinical term that refers to male pattern baldness) saw an almost 16 percent increase in hair count around the crown (a common area for male pattern baldness) after using finasteride for two years.
A longer-term study conducted in Japan produced even more dramatic results. Of the 532 men that took part in the study, 99.1 percent experienced no further hair loss after taking finasteride over a period of 10 years.
Additionally, 91.5 percent of the men experienced increases in hair density throughout the study period.
In short, finasteride treatment works well, with studies showing real, measurable improvements in hair density, coverage and regrowth of hair.
So, how long does finasteride take to work? As a medication, finasteride starts working as soon as it’s absorbed by your body.
This means that you’ll start blocking the conversion of testosterone to DHT and have lower DHT levels as soon as the first dose of finasteride gets into your system.
However, this doesn’t mean that you’ll be able to see an immediate reduction in hair loss or any changes in the thickness of your hair.
Your hair grows through a multi-phase process that’s referred to as the hair growth cycle. When each hair is in its anagen phase, or growth phase, it can take anywhere from two to six years to grow to its full length.
This means that even though finasteride starts working immediately, you shouldn’t expect to see any changes in your hair for several months of treatment, even if you’re using the medication as directed.
Rest assured that finasteride is actively working. Over time, finasteride begins to accumulate in your body, meaning that a modest daily dose (typically 1mg) is enough to significantly reduce DHT production and act as a treatment for hair loss.
Provided you follow the instructions and take finasteride daily, data from clinical trials generally suggests that you’ll start to see results from finasteride by month three or four.
These may include stabilization of hair loss in areas such as your hairline and/or crown, a mild but noticeable improvement in hair thickness, or a reduction in the average amount of hair you shed on a daily basis.
However, it generally takes six to nine months to see the full effects of finasteride, because your hair follicles require plenty of time to produce new hairs.
It’s important to remember that finasteride doesn’t always cause you to regrow hairs that you’ve previously lost.
Most men who use finasteride do so to stop further male pattern hair loss, rather than as a way to regrow hair and develop increased hair density.
This means that you may not notice any improvement in your hair from finasteride, even though it’s constantly working to prevent any extra hair from falling out.
In general, it’s best to think of three possible outcomes from finasteride:
Your hair loss slows down. After you start using finasteride, you may still continue to lose hair, but with a reduction of hair shedding and slower overall hair loss.
Your hair loss stabilizes. You might not grow back any hair after using finasteride, but your hair may stop actively falling out and remain in its current state.
Some of your hair grows back. Your hair may gradually start to grow back in areas of your scalp that have noticeable thinning.
Our guide to finasteride before and after photos explains how you can track your progress while using finasteride and shares real hair loss before and after examples.
Since male pattern baldness can vary in severity, it’s impossible to know what results you’ll get from finasteride before you start treatment.
It’s also important to remember that you’ll still shed some hair, even if you take finasteride on a daily basis.
It’s normal to lose approximately 100 hairs per day, even if you’re not balding. This level of hair shedding occurs as part of your hair’s growth cycle, and it shouldn’t be viewed as evidence that finasteride isn’t working.
So, how long does it take finasteride to work? Although finasteride works right away in terms of reducing serum dihydrotestosterone concentrations, it usually takes several months before your results will be noticeable, with more significant results visible after around nine months.
One of the best ways to use finasteride is in combination with minoxidil, a topical medication that stimulates hair growth.
Though its exact mechanism of action still isn’t fully understood, minoxidil is believed to work by shortening the telogen (resting) phase of the hair growth cycle and moving hair follicles into the anagen (growth) phase. It also stimulates blood flow to the scalp, which may help to promote hair growth.
Research has found that finasteride and minoxidil are more effective at stopping hair loss and promoting hair growth when used together than when used separately.
For example, in a study published in the journal Dermatologic Therapy, researchers compared the effects of minoxidil and finasteride alone with a combination of the two medications.
They found that 59 percent of the men treated with minoxidil experienced improvements at the end of a 12-month treatment period, as did 80.5 percent of the men treated with finasteride.
In comparison, 94.1 percent of the men who used both medications over the same time period showed improvements.
We offer minoxidil and finasteride together with other evidence-based products for treating hair loss in our Hair Power Pack.
Unlike finasteride, which comes in tablet form, minoxidil is available as a solution or foam that’s applied directly to your scalp. It’s typically used twice daily to stimulate hair growth and reduce the severity of male pattern baldness.
Our guide to applying minoxidil explains how to use minoxidil properly, as well as what to expect from this type of hair loss medication.
Pattern hair loss can vary hugely in severity from one man to another, meaning there’s no exact period of time in which you can expect to see the final results from finasteride.
Most of the time, you’ll be able to see significant results from finasteride after about nine months to one year of consistent use.
It’s important to take finasteride on a daily basis. If you skip finasteride tablets, forget to take the medication or take it at a reduced dosage, you may not experience the full effects.
It’s also important to keep in mind that there’s no specific, one-size-fits-all results profile that you can expect from finasteride.
For some guys, finasteride completely stops hair loss and promotes substantial, noticeable hair regrowth.
For others, finasteride may simply slow hair loss, or prevent hair loss from getting worse without producing any noticeable regrowth.
The key thing to keep in mind is that you shouldn’t stop taking finasteride just because it doesn’t produce any visible improvement in your hairline or hair thickness.
If you stop taking finasteride, your DHT levels will go back to normal and you could begin to lose hair again.
Finasteride is a safe, effective medication for most men. The majority of men with hair loss who take finasteride experience a reduction in hair loss and improvements in hair growth with few or no adverse effects.
However, finasteride does cause side effects in a small percentage of men, including some side effects that may affect your sexual desire and performance.
Potential side effects of finasteride include:
Decrease in sex drive
Erectile dysfunction (ED)
These side effects are not common. For example, decreased libido, which is the most common side effect of finasteride reported in clinical trials, occurred in 1.8 percent of men treated with a normal dose of finasteride, versus 1.3 percent of men treated with a placebo.
Our guide to finasteride side effects goes into more detail about the adverse effects associated with finasteride, as well as what you should know before using this medication.
If you have concerns about using finasteride due to its side effects, you might want to consider topical finasteride.
This type of finasteride is applied to your scalp, allowing it to target DHT that can attach to your hair follicles without affecting tissue elsewhere in your body. This can lower your risk of dealing with systemic side effects that may occur with oral finasteride.
We offer a Topical Finasteride and Minoxidil Spray that’s designed to target scalp hair loss from multiple angles.
“I tried several different options before but Hims combined approach of all four methods by far created the best results.”
“Hims has been the greatest confidence boost, no more bald jokes! I look and feel so much younger!”
“When I show my barber my progress, he is always in disbelief. I have to recommend Hims to any guy who’s experiencing thinning.”
“Cost effective and affordable. My hair keeps growing thicker, fuller, and at a fast rate.”
“I noticed a huge change in the overall health and fullness of my hairline.”
“Now after 5 months I’m able to style waves first time in 10 years!”
“I decided to jump right in and I'm so glad I did. I definitely feel ten years younger!”
“In just as little over two and half months, I can really see the difference in thickness and in color.”
“4-months strong and my confidence boosted back up to 100% using Hims, future me really does thank me.”
“I’m a 34 year old father of two and have been using Hims for over a year now. My hair is back to what it was in my mid twenties.”
In addition to using finasteride and minoxidil together, there are several things that you can do to promote healthy hair growth and get the best results from finasteride:
Use a hair loss prevention shampoo. Look for shampoos that are formulated using saw palmetto or ketoconazole, which may help to lower DHT levels and prevent male pattern baldness.
Our Thick Fix Thickening Shampoo features saw palmetto to target DHT and promote extra volume and moisture.
Eat a balanced, healthy diet. While diet doesn’t appear to play a role in male pattern baldness, eating a balanced, healthy diet helps to provide your body with the vitamins, minerals and other nutrients it needs to support healthy hair growth.
Our guide to the best foods for hair growth shares nutritious ingredients to add to your diet for stronger, healthier hair.
Make small, hair-friendly changes to your lifestyle. Simple things such as reducing your levels of stress (a common cause of telogen effluvium hair shedding) and limiting your use of irritating hair products can have a big impact on the health of your hair.
Our guide to lifestyle changes for improved hair growth shares simple changes that you can make to your habits to fight against hair loss.
If you get side effects, let your healthcare provider know. Although finasteride is a safe and effective medication for most guys, it can cause side effects, including sexual side effects.
If you experience any of the side effects of finasteride, make sure to let your healthcare provider know as soon as you can.
Finasteride is currently the most well-studied, effective medication available for the treatment of hair loss.
How long does finasteride take to work? If you’re beginning to lose your hair, you can expect to see some improvements from finasteride after three to four months of use, with more significant results visible after approximately one year.
Remember to keep using finasteride every day, even if you don’t notice any improvements right away. It takes time to regrow hair, and patience is very much a virtue when it comes to stopping androgenic alopecia.
If you’re starting to lose your hair and want to take action, you can access finasteride and other hair loss medications online.
Finally, you can learn more about treating and preventing hair loss using finasteride in our guide to finasteride for hair loss.