Key takeaways:
Finasteride (Propecia) is a medication that treats genetic hair loss in men. It’s also sometimes prescribed off-label for women. Finasteride works by lowering levels of a hormone called dihydrotestosterone (DHT), which causes hair loss.
It only takes one dose of finasteride to lower DHT levels. But it can take 3 months or longer to start seeing hair regrowth once you start taking it.
Finasteride only works while you’re taking it. Combining finasteride with other hair-loss treatments may improve your results. Hair loss will resume once you stop treatment.
With GoodRx for Hair Loss, you can pay as little as $16 per month for finasteride to help treat and prevent hair loss.
Save on related medications
There are many different factors that can cause hair loss, such as stress or autoimmune conditions. But the most common cause of hair loss is genetic. It’s officially called androgenetic alopecia, but it’s often referred to as male- or female-pattern baldness. And finasteride (Propecia) is a common treatment option for it.
Finasteride is most often prescribed for men. But it’s sometimes prescribed off-label for women, too. If your prescriber recommends finasteride, it’s common to wonder what it actually does to treat hair loss. And how long does it take for finasteride to work? We’ll answer these and more common finasteride questions below.
1. How does finasteride work?
Finasteride lowers the levels of dihydrotestosterone (DHT), a hormone that contributes to hair loss.
DHT is formed from testosterone by an enzyme (protein) called 5-alpha reductase. Finasteride blocks this enzyme, which lowers DHT levels and helps prevent hair loss. This is why finasteride is referred to as a 5-alpha reductase inhibitor.
2. How long does it take finasteride to work for hair loss?
Finasteride starts lowering DHT levels right away. Clinical studies show a 65% decrease in DHT levels within 24 hours of the first dose. This helps prevent further hair loss. However, hair regrowth happens over time, so it takes longer to start seeing visible results from finasteride.
Here’s a general timeline:
Months 1-3: Hair loss stops
Months 3-6: Hair begins to regrow
Month 6-12: Significant hair growth expected
Some people don’t have visible results in the first year of finasteride treatment. But a long-term study found that if you keep taking it, visible results will likely appear later on.
3. Can finasteride regrow hair?
Yes, long-term finasteride treatment can help increase the amount of hair you have. The majority of hair regrowth seems to happen in the first 2 years of taking finasteride. But keep in mind that continued treatment still prevents further hair loss.
Finasteride also seems to work better at regrowing hair the earlier you start taking it. Studies suggest it's best to start taking finasteride as soon as you notice hair loss. Finasteride may help regrow a receding hairline, but it’s likely to be more effective for balding that starts at the crown of the head.
4. Is there anything you can do to make finasteride work faster?
There’s not a way to make finasteride work faster. But as mentioned, you’ll have better results the sooner you begin the medication once hair loss starts.
You may also want to talk to your care team about combining finasteride with other treatments. Adding topical minoxidil (Rogaine) or laser therapy to finasteride may help prevent hair loss and regrow hair. Platelet rich plasma (PRP) injections have also been effective when combined with finasteride treatment in studies.
Good to know: Higher doses of finasteride (Proscar 5 mg) are used to treat a prostate condition called benign prostatic hyperplasia. But higher doses aren’t more effective than lower doses (1 mg) for hair loss. And higher doses of finasteride also have a greater risk of side effects. So it’s best to stick with 1 mg of finasteride for hair loss unless your prescriber tells you otherwise.
5. Does finasteride affect testosterone levels?
Finasteride stops some testosterone from being turned into DHT. As a result, you may have an increase in testosterone levels (up to 25%) when you start taking it. But this increase doesn’t seem to cause any issues and may not have noticeable effects for most people.
Treatments for hair loss: Learn which hair-loss treatments work best, along with natural ways to help regrow hair.
Finasteride side effects: Here are common and rare finasteride side effects to keep an eye out for while you’re taking it.
Finaseride vs. minoxidil: Review the key differences between these two hair-loss medications to help you find the right option for your needs.
However, finasteride may cause erectile dysfunction and low libido (sexual desire) in some men, despite the fact that it increases testosterone levels. It’s not clear why this happens, and it’s less common with low finasteride doses. But let your care team know if sex-related side effects are an issue for you. A different hair-loss treatment may be a better option.
6. How long does finasteride stay in your system?
Finasteride doesn’t last very long in your body. It takes about 30 hours (a little over 1 day) to clear it after your last dose.
Keep in mind that if you stop taking finasteride, its DHT-blocking effects will also stop. Your DHT levels will return to normal within about 14 days (2 weeks). And your hair loss will likely resume, as well.
7. How long do you have to take finasteride?
You need to keep taking finasteride daily in order for it to keep working. As mentioned, once you stop taking it, your DHT levels will go back up and hair loss will resume. Most people will lose any regrown hair within 12 months of stopping finasteride treatment.
8. Is finasteride safe to take?
Finasteride is generally considered safe. But, it’s a good idea to talk to your care team about possible risks and side effects before you take it. This will help you make an informed decision as to whether it’s the right treatment option for you.
The most common finasteride side effects include erectile dysfunction and low libido. Depression is also possible, as well as enlarged breasts in males. These side effects are more common with higher doses of finasteride. But they’re still possible at any dose.
What’s more, these side effects may persist even after you stop taking finasteride. This wasn’t common in clinical studies, but it seems that this issue, known as post-finasteride syndrome, may be more common than previously thought.
Finasteride may also raise the risk of a certain type of severe prostate cancer. But it also lowers the risk of prostate cancer in general. So the overall risk remains unclear.
Your healthcare team can help you decide if finasteride is a safe treatment option for you, based on your medical history and other health conditions.
Good to know: Finasteride can interfere in the growth and development of a fetus. Avoid taking — or even touching — finasteride tablets if you’re pregnant or trying to become pregnant.
9. What if finasteride does not work for you?
Finasteride may not work for everyone. If you don’t notice any improvement after 6 to 12 months of treatment, or side effects are too bothersome for you, there are other hair-loss treatments to consider. But keep in mind that some people don’t see results until after more than a year of finasteride treatment.
Finasteride alternatives include:
PRP injections
Steroid injections
Different treatments are more effective for certain types of hair loss. Your prescriber can help you find the right hair-loss treatment for your needs.
How to save on finasteride
There are ways to save on finasteride, which is available as both a brand-name and generic medication:
Save with GoodRx for Hair Loss: Pay as little as $16 per month for finasteride, which includes a telehealth visit, treatment, and home delivery at one low cost.
Save at the pharmacy with a GoodRx discount: Generic finasteride’s price at the 1 mg dose for hair loss at certain pharmacies is as low as $9.30 with a free GoodRx discount.
The bottom line
Finasteride (Propecia) is a prescription hair-loss medication. It works by lowering levels of a hormone called dihydrotestosterone (DHT) that causes hair loss.
Finasteride lowers DHT levels after just one dose. But it can take 3 months or longer to start seeing hair regrowth. Combining finasteride with other hair-loss treatments may improve your results. But finasteride only works while you’re taking it — hair loss will likely resume once you stop treatment.
Finasteride is generally considered safe, but there are some risks and side effects to be aware of before you take it. Your healthcare team can help you decide if finasteride is a good treatment option for your needs.
Why trust our experts?
References
Abdin, R., et al. (2022). Treatment of androgenetic alopecia using PRP to target dysregulated mechanisms and pathways. Frontiers in Medicine.
American Academy of Dermatology Association. (2022). Hair loss: Diagnosis and treatment.
Anitha, B., et al. (2009). Finasteride-its impact on sexual function and prostate cancer. Journal of Cutaneous and Aesthetic Surgery.
Ascend Laboratories. (2025). Finasteride- finasteride tablet, coated [package insert].
Bryant Ranch Prepack. (2024). Finasteride- finasteride tablet, coated [package insert].
Ho, C. H., et al. (2024). Androgenetic alopecia. StatPearls.
Kinter, K. J., et al. (2023). Biochemistry, dihydrotestosterone. StatPearls.
Organization of Teratology Information Specialists. (2024). Finasteride. MotherToBaby.
Rossi, A., et al. (2011). Finasteride, 1 mg daily administration on male androgenetic alopecia in different age groups: 10-year follow-up. Dermatologic Therapy.
Salisbury, B. H., et al. (2024). 5-alpha-reductase inhibitors. StatPearls.
Traish, A. M. (2020). Post-finasteride syndrome: A surmountable challenge for clinicians. Fertility and Sterility.
Wang, L., et al. (2020). Association of finasteride with prostate cancer: A systematic review and meta-analysis. Medicine.
Zito, P. M., et al. (2024). Finasteride. StatPearls.
