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If you are taking finasteride for hair loss, you may be wondering what might happen if you stop taking it. Will your hair thin out again, or will taking it cure your hair loss? Are there side effects you can expect when you stop taking finasteride? Read on to explore.
How does finasteride work?
Finasteride (brand names Propecia or Proscar, see Important Safety Information) is an oral medication that’s FDA-approved to treat hair loss in men with androgenic alopecia. Androgenic alopecia, or male pattern baldness, is a hereditary condition and the leading cause of hair loss in men. (This condition also causes female pattern baldness, but finasteride is not FDA-approved in women, though it is sometimes prescribed off-label for women). Men with male pattern baldness have an increased sensitivity to dihydrotestosterone (DHT), along with higher levels of DHT (Ho, 2022; Zito, 2022).
Like testosterone, DHT is an androgen, or male sex hormone. While DHT aids in hair growth during puberty—you can thank DHT for your armpit and pubic hair—it can contribute to hair loss later in life by shortening the growth stage of hair follicles (Kinter, 2022). At high levels, this leads to shorter and thinner hairs, and eventually, visible hair loss. Finasteride works by blocking an enzyme called 5-alpha-reductase from converting testosterone into DHT, effectively halting DHT production in its tracks. As a result, future hair loss slows down, and hair growth may improve (Ho, 2022; Zito, 2022).
Studies show that taking 1 mg of finasteride daily can increase hair regrowth and slow down hair loss (Ho, 2022). The hair regrowth effects of finasteride can be visible as early as three months after starting the drug. Studies show that finasteride continues to be effective for years, increasing hair growth for 65% of men within one year, 80% of men within two years, and 77% of men at five years (DailyMed, 2021).
Higher doses of finasteride (5 mg) may also be prescribed to treat benign prostatic hyperplasia (BPH), which is an enlarged prostate (Zito, 2022).
What happens if you stop taking finasteride?
Finasteride is a hair loss treatment, not a cure. Like other 5-alpha-reductase inhibitors (5-ARIs), DHT-blocking medications like finasteride only work while you are actively taking them. When you take finasteride, the drug blocks testosterone from converting to DHT and attacking your hair follicles. Once you stop taking finasteride, there is no longer anything blocking this conversion from happening, so your body resumes converting testosterone to DHT and the hair follicles respond in turn (Ho, 2022; Zito, 2022).
Because finasteride only works while the drug is active in your body, you need to continue taking finasteride as long as you want its results. On average, the drug lasts five to six hours in men up to 60 years old, and up to eight hours in men older than 70, so it needs to be taken daily (Zito, 2022).
Once you stop taking finasteride, the amount of the active drug in your body will decline over a few weeks until there is nothing left. At that time, your body will resume converting testosterone into DHT (Ho, 2022; Zito, 2022).
If you are genetically predisposed to male pattern hair loss, as 50% of men are by age 50, this conversion to DHT can lead to thinning hair, receding hairlines, and other noticeable side effects of stopping finasteride. Within one year, you may lose all the hair you gained while you were taking finasteride daily (Ho, 2022; Zito, 2022).
Typically, any side effects you experience while taking finasteride go away once you stop taking it. Often, these are mild and affect a small number of men, between 2% to 4%. The most common side effects of finasteride include (DailyMed, 2021; Zito, 2022):
Additional side effects may include gynecomastia (male breast growth), skin rash, dizziness, weakness, stuffy nose, or shortness of breath (Zito, 2022; DailyMed, 2021). Side effects may be more common when finasteride is taken in higher doses of 5 mg for BPH (enlarged prostate), especially sexual side effects such as low libido and ejaculation volume. These side effects usually stop when you stop taking finasteride, although they may persist as post-finasteride syndrome (Pereira, 2020).
Post-finasteride syndrome is a rare condition characterized by adverse effects on a person’s physical, mental, and sexual functioning for at least three months after they stop taking finasteride. These may include (Pereira, 2020):
- Sexual side effects, such as reduced sex drive, erectile dysfunction, reduced semen production, penile changes, or reduced sensitivity or pleasure during orgasm
- Physical side effects such as gynecomastia (male breast growth), chronic fatigue, dry skin, joint or muscle pain, or muscle weakness
- Mental side effects such as depression, anxiety, panic attacks, insomnia, suicidal thoughts, or problems with memory or comprehension
The research into post-finasteride syndrome is still developing and there is no known cure at this time (Pereira, 2020). Talk to your healthcare provider if you notice any side effects while taking finasteride.
How long can you take finasteride?
Finasteride only works to prevent hair loss as long as you keep taking it. Fortunately, finasteride is considered a safe and well-tolerated medication that you can take for years (Pereira, 2020; Hirshburg, 2016).
Several studies have demonstrated that daily doses of 1 mg of finasteride are safe and well-tolerated for periods ranging from one to seven years (DailyMed, 2021; Shin, 2019). A longer study found that the drug continued to be well-tolerated and effective in treating hair loss at a 10-year follow up (Yanagisawa, 2019).
Taking finasteride at a higher dose for BPH may present more risk, although researchers still conclude it is safe for long-term use (Unger, 2016).
Finasteride is not a cure for male pattern baldness, but rather, a long-term treatment. To avoid hair loss from resuming, talk to your healthcare provider before stopping finasteride treatment.
If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
- DailyMed. (2021). PROPECIA- finasteride tablet, film coated. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4e07adb4-7807-47d3-b9a9-2332a3047410
- Diviccaro, S., Melcangi, R. C., & Giatti, S. (2019). Post-finasteride syndrome: An emerging clinical problem. Neurobiology of Stress, 12, 100209. doi:10.1016/j.ynstr.2019.100209. Retrieved from https://pubmed.ncbi.nlm.nih.gov/32435662/
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- Shin, J. W., Chung, E. H., Kim, M. B., et al. (2019). Evaluation of long-term efficacy of finasteride in Korean men with androgenetic alopecia using the basic and specific classification system. The Journal of Dermatology, 46(2), 139–143. doi:10.1111/1346-8138.14719. Retrieved from https://pubmed.ncbi.nlm.nih.gov/30536893/
- Thompson, I. M., Jr, Goodman, P. J., Tangen, C. M., et al. (2013). Long-term survival of participants in the prostate cancer prevention trial. The New England Journal of Medicine, 369(7), 603–610. doi:10.1056/NEJMoa1215932. Retrieved from https://pubmed.ncbi.nlm.nih.gov/23944298/
- Unger, J. M., Till, C., Thompson, I. M., Jr, et al. (2016). Long-term consequences of finasteride vs placebo in the prostate cancer prevention trial. Journal of the National Cancer Institute, 108(12), djw168. doi:10.1093/jnci/djw168. Retrieved from https://pubmed.ncbi.nlm.nih.gov/27565902/
- Yanagisawa, M., Fujimaki, H., Takeda, A., et al. (2019). Long-term (10-year) efficacy of finasteride in 523 Japanese men with androgenetic alopecia. Clinical Research and Trials, 5(5). doi:10.15761/crt.1000273. Retrieved from https://www.oatext.com/Long-term-(10-year)-efficacy-of-finasteride-in-523-Japanese-men-with-androgenetic-alopecia.php
- Zito, P. M., Bistas, K. G., & Syed, K. (2022). Finasteride. StatPearls. Retrieved on Jan. 13, 2023 from https://www.ncbi.nlm.nih.gov/books/NBK513329/
Dr. Chimene Richa is a board-certified Ophthalmologist and Senior Medical Writer/Reviewer at Ro.