Medically reviewed by Vicky Davis, FNP
Written by Our Editorial Team
Last updated 8/12/2021
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, 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 might take several months before you’re able to see any improvements in the thickness, density and general appearance of your hair.
Below, we’ve explained what finasteride is, as well as how it works as a treatment for hair loss in men.
We’ve also discussed how long finasteride takes to work, as well as techniques that you may be able to use for faster, better results.
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 can bind to receptors in the prostate gland and contribute to issues such as benign prostatic hyperplasia (BPH, or enlarged prostate).
Another is male pattern baldness. In men genetically predisposed to hair loss, 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 into DHT.
This significantly lowers the amount of DHT that’s present in your bloodstream and shields your hair follicles from DHT-related damage.
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 amount of hair regrowth.
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 some degree of regrowth of hair throughout the study period.
In short, finasteride works, with most studies showing real improvements in hair growth, density and coverage.
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 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 the anagen, 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, 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, although it may vary) is enough to significantly reduce DHT production and keep your hair protected.
Related read: Should I Take Finasteride?
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 some mild regrowth in areas of your scalp with thinning hair, or a decrease in the 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.
This means that you may not notice any improvement in your hair from finasteride, even though it’s constantly working by preventing 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 at a slower rate than normal.
Your hair loss stabilizes. You may 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.
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 between 50 and 100 hairs per day, even if you’re not going bald. This level of hair shedding occurs as part of your hair’s natural growth cycle, and shouldn’t be thought of as evidence that finasteride isn’t working.
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One of the best ways to use finasteride is in combination with minoxidil, a topical medication that stimulates hair growth.
Minoxidil works 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 over the course of 12 months, 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, along with other science-based products for treating hair loss, in our Hair Power Pack.
Unlike finasteride, which comes in tablet form, minoxidil is available as a liquid or foam that’s applied directly to your scalp.
Our guide to applying minoxidil explains how to use it, as well as what to expect from this type of hair loss medication.
Hair loss can vary 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 approximately 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 their natural amount and you could start to lose hair again.
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 Hair 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.
If you’re starting to lose your hair, you can expect to see some improvements from finasteride in three to four months, 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 hair loss.
If you’re starting to lose your hair and want to take action, you can access finasteride and other hair loss treatments online.Finally, you can learn more about treating and preventing hair loss with finasteride in our guide to what every man should know about finasteride for hair loss.
Related read: Finasteride before and after photos