Does Finasteride Work after 20 Years?

Dihydrotestosterone (DHT) inhibitor finasteride was first approved by the US FDA to treat hair loss in 1997. The original brand name from its US based manufacturer Merck was Propecia.

The only other drug that has ever been approved by the FDA to treat hair loss is topical minoxidil (brand name Rogaine). In Japan and South Korea, dutasteride has also been approved to treat hair loss.

Long-Term Finasteride Studies

Finasteride 10 Years
A time-series progression of hair growth from daily Finasteride use over 10 years in a Japanese patient. © Yanagisawa M (2019).

Although finasteride was approved to treat hair loss 26 years ago, there are very few studies in existence that even attempt to analyze 5-year plus results. I found two that covered 10 years.

It is extremely difficult to get hair loss sufferers to come back to the same clinic regularly for 10 years and have their scalps analyzed. Moreover, many patients tend to stop using the drug after some years due to side effects or loss of motivation. Some might also alter their dosage without consulting their physician.

Many hair loss patients also add other drugs and products into the mix. This makes it impossible to determine the exact solo impact of finasteride on their hair.

The image on the right is from a Japanese patient who is taking finasteride for his hair loss. It shows the results at first visit, followed by annual follow-up visits from years 1 through 10. He is part of a long-term study of 523 Japanese patients who took 1 mg/day finasteride to treat their androgenetic alopecia for 10 years.

According to the authors of this study:

“A high objective efficacy was demonstrated by the modified global photographic assessment score (MGPA). It revealed improvement and prevention of disease progression in 99.1% of the 532 Japanese men with AGA treated with 1 mg/day finasteride for 10 years.”

Amazingly, these Japanese men continued to see new hair growth even after years of finasteride 1 mg/day use. In fact, many patients even saw new hair growth at the 10 year mark! Furthermore, most patients saw an improvement from year 5 to year 10.

The average Japanese androgenetic alopecia (AGA ) patient in this study saw an improvement of approximately 1 Norwood scale grade after 10 years of treatment with finasteride. Side effects remained minimal even after such long-term use. I am surprised at such a high 99.1% success rate after 10 years. It is beyond amazing.

I always assumed that the human body develops some tolerance to finasteride after 10 years of use (just as with repetitive intake of antibiotics, alcohol etc). Moreover, finasteride only reduces serum DHT levels by 70% (and scalp DHT levels by 64%). Surely the other 30% keeps causing some damage to hair follicles?

Online anecdotal reports (from the English speaking world) suggest that a majority of long-term finasteride users seem dissatisfied in the long run. Perhaps the first point below explains this anomaly.

  • These same Japanese authors published an 801-person (5-years of finasteride use) study in 2015 that concluded that Japanese hair loss sufferers are much better responders to finasteride than are Caucasian men. For comparison, they cited a prior large-scale 1,553 person study on Caucasian men that showed a 48% improvement after 5 years. Nevertheless, Caucausian men are still great responders after 5 years. The same authors also did a 2.5-year report (3,177 patients) with similarly favorable results in Japanese men. A summary of their 2.5-, 5-, and 10-year results can be read here.
  • In 2011, a team from Italy published 10-year results of 1 mg/day finasteride use in 181 men. The overall results were also quite favorable in this report, although there were some significant diffference between various age groups of patients. After 10 years, almost 70% of patients who experienced growth in their first year experienced continued growth. Moreover, in 21% of cases, treatment continuation beyond 5 years provided even better results. All the more resons to not give up on finasteride if you are seeing no side effects.
  • A study on finasteride use for treating benign prostatic hyperplasia (BPH) for 7-8 years showed maintenance of results and low rates of side effects.

According to Dr. Robert Bernstein:

“Although finasteride will usually continue to work as long as you take it, it may lose some of its efficacy over time. Generally after about 5 years we may notice that the patient’s hair is starting to thin again and we will increase the dose slightly.

However, he cautions that even if someone keeps thinning while on finasteride, it does not necessarily mean that the medicine is not working. The same person might have thinned much more without taking the drug.

20 Year Results

I hope that our Japanese friends maintain their discipline and release a fourth study with 15-year results by 2025. I doubt that we will ever see anyone pubish 20-year results, but hope I am wrong. In the invaluable ongoing Japanese effort, the dropoff in patients counted from 2.5 to 5 to 10 years of follow-up was 3,177 to 801 to 523 respectively. By the 20 year mark, I do not expect more than 100 people will have returned each year, even if photos are taken remotely.

Based on the findings that I discussed in this post, I am encouraged to keep using my dutasteride (which is superior to finasteride and has a much longer half life). However, I just take one 0.5 mg pill every week due to a fear of side effects. I am also wary about the long-term effects of finasteride (and dutasteride) on estrogen and testosterone levels, although there is no evidence as yet of any major changes.

Make sure to also check out my past posts on finasteride and dutasteride dosage discussion; and on finasteride and low-dose dutasteride combination treatment.

33 thoughts on “Does Finasteride Work after 20 Years?”

  1. Serious question, have you considered switching to cosmerna, or are you waiting for 6 months post release to judge?

    1. Waiting for 1 year feedback. It is also hard to trust all the CosmeRNA stuff on Reddit :-(

      I am on oral Dut and oral Min. Am 50/50 about adding a third product.

      1. I’m just on my 5th month of LLLT after switching away from topical min, tried fin in the past and didn’t get on with it, I’ll likely switch to cosmerna only next month and then depending on how that works perhaps niostem Spring 24.
        The cosmerna subreddit is full of some of the most dysfunctional posters I’ve seen outside of 4chan but if niostem works as well as the company says, it’s basically a hair transplant – I can’t understand why more people aren’t talking about it.

        1. Seriously you think niostem is legit and will help growth new hair ?
          Four Cosmerna application, and still nothing

          1. I wrote *if* it works as well as well as the company says (i.e., ~40 hairs/cm2), then that’s basically in the ballpark of transplant density. Who knows they could be whistling Dixie, but we’ll soon find out….

            Isn’t cosmerna meant to primarily be a maintenance treatment anyway?

  2. I started at a nw5 but have been on finasteride for 6 years now. I never thought a drug could be a miracle but finasteride is a modern day medical miracle drug for sure. I hope It continues to work for me.

    1. Dude woofy97 honestly what’s the point of taking finasteride if you’re a Norwood 5 that’s basically being bald.

  3. I took fin 5mg divided by 4 = 1.25 mg everyday for close to 25 years. Worked well in tandem with high strength minox. However at around 20 years it started to loose effectiveness. I bumped up to 2.5 mg everyday, didn’t give that much time and switched to .5mg of dut everyday. That helped, plus oral minox. So yeah, for me I can say that fin lost it’s effectiveness, starting to wonder if pretty much everything does over time, on me anyways. Hair took a big hit lately, stress and CV19 related, still holding hope I get back my gains, maybe seeing some green shoots…or maybe not.

  4. Hello,
    Do you know how long it takes for the DHT to go back up after staggered doses? I usually take at midnight but having missed a dose I took the next day at 6 a.m. and then I gradually shifted the doses to 11 a.m. then 4 p.m. then 11 p.m. before resuming at midnight.
    Do you think these changes may have caused my DHT levels to rise again?

  5. I’ve been taking finasteride for over 20 years, and it still works, but you have to take it every day, the 3 days a week deal doesn’t work as good.

  6. If only they could get the side effects out of fin. I know many that have no side effects but it’s a huge risk. Like anything else I guess. I do think it helps immensely though for those that don’t mind the sides or don’t get any. I need to look up the sides for dut again. It’s been a while.

    As far as niostem, nobody is going to convince me any kind of helmet or light device is going to grow significant hair. I’m sorry. I know there are studies (that are suspect imo) and some swear by it, but it all screams scam to me. Their claims are too large to be legit.

    As far as CosmeRNA, I have very little hope it will do anything at all. Yes yes I know people are only on their 4th or 5th application and it’ll take time (they all say it’ll take time so while everyone waits sales continue). But I’ll put my vote on “does nothing” anyway.

  7. It does work pretty well, but the issue is I think a lot of people get side effects. Then your really hosed, because its literally the only real thing that works before you go into the rabbit hole of a million things that might help a little but lack evidence.

  8. Biggest issue with Fin is of course the sides that many ppl suffer, despite official stats…What r peoples views on Pyrilutimide, allegedly stronger Fin but no sides?

    I’m really excited about it, BUT temper the excitement by the fact that plenty r using it via other sources and I don’t see anyone shouting from the rooftops about efficacy.

  9. I haven’t missed a dose , 1mg , of Fin since 2007. I’m 38, both brothers are NW7. I’m a NW 2.5, with severe diffuse thinning , but able to mask it with concealers. I’m really depressed about my hair line because no matter what style I choose, it doesn’t frame my face right. I’m getting tired of dealing with this.

    1. Hello Alexander, same happened to me.
      After 8 years it lost efficacy. I switched to Dutasteride after two more years and regained what I lost in those two years. That was in 2010. Started in May 2021 with OM. Hair sort of ok now. Waiting for Niostem for an additional boost. Perhaps CosmeRNA next year…
      Therefore, you have options…use them.
      Do those new treatments help…no idea.
      I will find out.
      But I can’t afford not testing them.

        1. 0.5mg daily as directed by my urologist.
          Its covered in my country by insurance because it’s prescribed to treat BPH.

          1. I pay $25 for 90 pills form Costco, generic .5mg no insurance, cash. Still need a doc’s RX of course, not for BPH, can be off label.

  10. Dut was an improvement after fin became less effective. However adding oral minoxidil was what really helped. At my age, as long as I’ve been fighting hair loss (40 years) I need to attack from all angles, orally and topically (high strength minox, dut and other goodies mixed in depending who’s topical I’m using at any given time). Never experienced any appreciable side-effects from any treatment, oral or topical.

      1. Hey Tim, I guess dut around 55 and oral minox around 58. I tried needling, even bought a derminator, don’t think it did much for me.

  11. I have a question. Why topical finasteride gives insane results for some people but for other people it literally does nothing. Is it something I’m missing?

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